text:
What is the most effective maximum work duration per day?
A related question asks about the best work-break schedule for an effective eight hour work day.
This question presupposes that eight hours of work per day is a good duration and that all you need is to optimize your work-break schedule. But research seems to hint that alertness and productivity might increase if you shorten your workday: A survey (Bielenski, 1994) asking managers about their experiences with part time work in eight European countries found a better quality of products or services. Part time work here includes all different kinds of reduced weekly working hours. A German (Infratest Sozialforschung, 1985) and American (Beyer, 1986) study on flexible work time models (including part time and gliding time) found an increase in production volume and quality, higher job satisfaction, and a decrease in lateness and absences.
Research also shows that performance increases if you increase your sleeping hours (e.g. from eight to ten hours per night), and it is a banal truth that the the amount of sleep that you can or want to allow yourself is directly related to the amount of work: eight hours of work plus taking care of the rest of your life only leave you so many hours to rest. So maybe the question of breaks doesn't even arise anymore, when you awake relaxed and highly attentive after enough sleep, and when you work focussed for four hours without breaks, knowing that you'll be free to enjoy yourself for the rest of the day.
Assuming on the one hand that you do in fact need time to get things done and cannot speed up your work frequency and shorten working hours indefinitely; and assuming on the other hand that you will get tired and work less well after a certain time; then there should be a turning point somewhere, where working longer or shorter decreases your productivity.
Of course the exact location of this point (and the optimal per day work duration) will differ for different kinds of tasks, so there will not be one optimum for everything. If there is more research on this topic than you can or want to cover in your answer, please focus on "intellectual work" (like that of scientists or in administration).
Question:
Is there research into how long you should work per day to be most effective?
I'm looking for a comprehensive and definite answer on this, and therefore I am especially interested in recent meta-analyses and overview articles, some of which might be published in handbooks or encyclopedias of occupational psychology and not available on the web.
No untested theories and no personal anecdotes, please.

Sources:

Beyer, H. T. (1986). Betriebliche Arbeitszeitflexibilisierung. München: Vahlen.

Bielenski, H. (ed.) (1994). New Forms of Work and Activity. Survey of Experiences at Establishment Level in Eight European Countries. Shankill: European Foundation for the Improvement of Living and Working Conditions.
Infratest Sozialforschung (1985). Flexible Arbeitszeiten: Erfahrungen aus der Praxis. Humanisierung des Arbeitslebens, vol. 68. Frankfurt am Main: Campus.

I pinged you on chat but that doesn't work out s you haven't been there for a while, if ever. Firstly, thank you for your bounties. Secondly, why are you leaving us? Thirdly, how nice of you to give away your rep before leaving. Sad to see you go.

And just to bugger you - +1 on this question ;-)

If you like to chat around ping me in the chat room

This is a part-answer to your question and it doesn't come from occupational psychology, but from expertise research.
Findings from Expertise Research
In their seminal paper on the role of deliberate practice for the acquisition of expert performance, Ericsson et al. (1993) report a number of constraints that play a role in the acquisition of expert performance. One of these constraints is the effort constraint. What is meant by this is that, in order to improve one's skill, one has to engage in deliberate practice, which by definition is an effortful activity that requires full concentration. It is clear that such an activity cannot be kept up for very large amounts of time. Ericsson et al. cite works by Welford (1968) and Woodford & Schlosberg (1954) (which I haven't read) that compare the efficiency of practice durations ranging from 1-8 hr a day. These studies find that there is

essentially no benefit from durations exceeding 4 hr per day and reduced benefit from practice exceeding 2 hr. (Ericsson et al., 1993, p.370)

The authors then report that studies on the aquisition of typing skill by Baddely & Longman (1978) and Dvorak et al. (1936), and studies on other perceptual motor skills (Henshaw & Holman, 1930) which

indicate that the effective duration of deliberate practice is may be closer to 1 hr per day. (Ibid.)

Finally, they cite a study by Pirelli & J.R. Anderson (1985) that found

no increased learning from doubling the number of training trials per session. (Ibid.)

Thereafter, Ericsson et al. (1993) turn to more intellectually demanding domains. They report on data from financially independent writers, who

tend to write only 4 hr per day, leaving the rest of the day for rest and recuperation (Cowley, 1959; Plimpton, 1977). (Ibid., p.371)

In their own study 1, which investigated violinists at music college, the authors found that the best students practiced on average 3.5 hr per day.
Maximum vs. Typical Performance
From these findings it seems that the optimal duration lies somewhere between 1 and 4 hours. But it's important to note that this only holds for conditions of maximal effort and full concentration. Furthermore these studies investigate the acquisition, not the execution of a skill, which presumably is more important in the workplace. I would still argue that they can still be relevant in a work context.
In io-psychology there is the distinction between maximum and typical performance. Everything I have said so far obviously refers to maximum performance. The intellectual work of a scientist that you mention in your question might fall into this category. I can also imagine that a software developer needs full concentration. Probably, though, periods that require maximum performance and those that "only" require typical performance alternate. The time limit for typical performance may be much longer.
So my answer is only a part answer in at least two ways: First it only provides information about the time limit for maximum performance. Second, the studies that I cite have not actually been done within an occupational setting.
References:

Baddeley, A. D., & Longman, D. J. A. (1978). The influence of length and frequency of training session on the rate of learning to type. Ergonomics, 21(8), 627-635.
Cowley, M.(Ed.). (1953). Writers at work: The Paris review interviews, second series. New York: Penguin Books.
Dvorak, A., Merrick, N. L., Dealey, W. L., & Ford, G. C. (1936). Typewriting behavior. New York: American Book Company.
Ericsson, K. A., Krampe, R. T., & Tesch-Römer, C. (1993). The role of deliberate practice in the acquisition of expert performance. Psychological Review, 100(3), 363–406. doi:10.1037/0033-295X.100.3.363 PDF
Pirolli, P. L., & Anderson, J. R. (1985). The role of practice in fact retrieval. Journal of experimental psychology: Learning, memory, and cognition, 11(1), 136.PDF
Plimpton, G. (Ed.). (1976). Writers at work: The Paris review interviews. New York: Viking Press.
Welford, A.T. (1968). Fundamentals of skill. London: Methuen.
Woodworth, R. S., & Schlosberg, H. (1954). Experimental psychology. New York: Holt, Rinehart & Winston.

I was extremly undecided about both your answers. They are both informative, well-researched and valuable to me. I would have liked to split the bounty and give each of you one half. Now that Skippy has left, my decision has become easy. Thank you for your great contribution, Jens!

It would appear that a 6 hour workday would obtain better results of productivity than a >=8 hour day.
In discussing the optimum length of a working day, I have taken a neurobiological approach and an occupational approach. As the individual is not an isolated organism;  social and environmental demands, mean that in determining what is a most productive  workday, needs to encompass the fact that the individual has other tasks to complete within a 24 hour cycle. The need for sleep, to maximise performance, also needs to be taken into consideration, within this context.
There are been much research showing the relationship between excessive work hours, resulting fatigue and decline in cognitive ability.  The effect is also magnified as the  working week progresses.  Following this, there is evidence that a reduced working day (from 8 hour) increases productivity:

Working time and productivity International Labour Ofﬁce Geneva
The Effects of Working Time on Productivity
and Firm Performance:
a research synthesis paper; has examined this subject extensively:

a. Reduction in hours and worker productivity evidence
  The potential theoretical and practical impact of a reduction in hours on productivity was assessed by
  the International Labour Organization (ILO) over twenty years ago (White, 1987). Improvements in
  the efficiency of labour utilization were evident from a century’s worth of research that found some
  productivity improvement following a reduction in hours, depending, of course, on the accompanying
  conditions and responses, in the medium if not the short term. Four types of reductions were
  distinguished, all of which remain relevant to today’s conditions. Each creates its own potential for
  productivity improvements that would offset much, if not all, of the initial costs associated with
  shorter working hours. The four types are: reductions in excessive hours, gradual reductions in
  standard hours, accelerated reductions in standard hours, and individualized options for reducing
  working hours. ...
a. Interactions between duration and employee-centered flexibility of work
  schedules
  Importantly, the effect of working time flexibility often interacts with the duration of working hours.
  Greater discretion or control over the timing of their work helps workers to alleviate some of the
  negative effects of long hours on the incidence of work-related injuries, illnesses and time stress
  (Boden, 2005; Costa et al., 2006; Dembe et al., 2007; Hughes and Parkes, 2007). ...
  Reduced variability of
  hours has almost as much influence as higher flexibility on work/life satisfaction (Costa et al., 2006).

There has also been research into the best time of day to work. Research suggests that the peak times for alertness are mid to late morning (approx 11am), followed by another, lessor, peak in the late afternoon (approx 5.30pm).
Circadian Rhythms.
Human beings have natural Ultradian cycles, that govern our behaviour. I am focusing on the circadian rhythm, which is the natural 24 hour cycle that governs our physiology. It would be logical to propose that working within this cycle, as opposed to enforcing routines that are in conflict with this cycle, would be beneficial to finding an optimal working day structure.

Wakefulness
  The longer the brain has been awake, the greater the spontaneous
  firing rates of cerebral cortex neurons with this increase being
  reversed by sleep. Another effect of wakefulness (which may or may
  not be related to this) is that it lowers the small stores of glycogen
  held in the astrocytes that can supply energy to the brain's
  neurons—one of the functions of sleep, it has been proposed, is to
  create the opportunity for them to be replenished.
Sleepiness   The longer the time spent awake, the greater the drive
  for sleep.  .....   The second factor is circadian, which varies with
  a 24 hour periodicity and is independent of the amount of preceding
  sleep or wakefulness. ....   Together, the homeostatic and circadian
  factors modulate the need for sleep and influence the balance between
  alertness and sleepiness. ....Neurobiology of sleep and wakefulness Robert W. McCarley and Christopher M Sinton (2008) doi:10.4249/scholarpedia.3313

The following charts provide a good visual representation of the bodies 24 hour cycle:
The pink line is the predicted alertness
The blue dots are recall data

chart taken from the followup to "Polyphasic Sleep: Facts and Myths" Dr Piotr Wozniak

image courtesy of File:Biological clock human.svg

I disagree with rethinking the smaller 90 minute work and break    cycles. My explanation for this is given clearly in this answer. There is evidence, even within a shorter workday, that the 90 minute cycle exists and breaks enhance performance. I am going to focus on the optimal total hours of a    working day.
There are various physical, emotional, mental, financial and environmental factors (eg job stability) that would cause a variation in what an optimal working day would be; so for the purposes of this question I am assuming we are discussing individuals, within the norms for these factors (ie not unwell in these areas or experiencing undue stress).
I am assuming that you want the focus of this answer to be on work, rather than sleep. So, without going into discussion about optimal sleep patterns; it follows, logically, that a regular, extended working day of, for example: 16 hours, would prohibit the individual from getting optimal sleep, which in turn affects performance. So, for the sake of this discussion, I am assuming that an optimal work day, takes into account the need to optimize sleep, and that the individual is doing so.
I'm not addressing shift work here; as the scope becomes too large.
The relationship between optimizing such activity as for example: playing the violin,  needs to take into account the effect on the fingers; whereas in office work, there is less propensity for such risk of repetitive strain or injury.
There has been research regarding compressed working weeks, the benefits of completely 5 days work on 4 days.

Full-time vs Part-Time work:
The following  provides evidence for and against job performance and comparisons between full-time and part-time work hours. It is interesting to note that the difference in these findings could be related to the reward system of the job. The differences in performance, could (and probably are) be linked to the capacity to increase earnings with improved performance vs a fixed wage rate.
Looking at this alone, it would suggest that shorter working hours promote better performance when financial rewards are offered for higher productivity. Which supports the notion of a shorter working day being more optimal for productivity.
Argument for Part-time over Full-time work:
(full-time work is classified as a 40 hour working week)

Part-time workers tend to be more productive, hour for hour, than full-time workers because it is easier to work at peak efficiency for short periods.

An interesting, if not obvious point, made by Berkley University HR.
Flexible Work Arrangements: Part-Time Work

A comparison of part-time vs. full-time salespeople from four U.S. direct selling companies that part-timers had greater job satisfaction and less propensity to quit. Part-timers were also better performers as measured by earnings per hour worked.

Another interesting finding in this study, opens a whole avenue for analysis, between having options and motivation upon performance.

When these same respondents were analyzed in terms of other jobs held simultaneously with their direct selling job, some evidence indicated that job satisfaction was lower while earnings per hour and propensity to quit were greater as the extent of other outside employment increased.

Full-time vs. part-time salespeople: A comparison on job satisfaction, performance, and turnover in direct selling
Thomas R. Wotruba doi.org/10.1016/0167-8116(90)90014-E
Argument for Full-time over Part-time work:
A interesting note with regard to the differences of work outcomes between full-time and part-time workers; the only notable difference is regard to job, the implication being that full-time workers are more likely to have a more responsible attitude towards their jobs. If the overall working week were to change, this difference would need to  be re-examined.

Employees who work fewer hours per week tend to assign less importance to the work outcomes measured in this study.

Differences in the importance of work outcomes between full-time and part-time hospital employees
Douglas S. Wakefield1, James P. Curry1, Charles W. Mueller2, James L. Price2
DOI: 10.1002/job.403008010
In studies on employee attitude, their was no difference between full-time and part-time workers.

A meta-analysis was conducted (k =38, N =51,231) to examine the size of the difference between full- and part-time employees on job attitudes. Results indicated that there was little difference between full-time (FT) and part-time (PT) employees on job satisfaction, organizational commitment, intentions to leave and facets of job satisfaction.Full-time employees were found to be more involved with their jobs than PT employees.

Job attitudes of part-time vs. full-time workers: A meta-analytic review
Todd J. Thorsteinson
DOI: 10.1348/0963179037659136
In terms of performing tasks beyond immediate job criteria, the results sway towards full-time employees rating better, but this is also not clearly defined. This could be linked towards employment attitude.

There are two types of performance: in-role and extra-role work performance or OCB ...
  Marchese and Ryan (2001) found significant differences between full-time and part-time workers in job performance. Full-time employees had a higher level of performance. Another study showed no significant
  difference between full-time and part-time workers in terms of performance (Wotruba, 1990)

A Comparison Between Full and Part-Time Lodging Employees on Job Satisfaction, Organizational Commitment, and Job Performance
Abdullah Al Omar, Jet al

Shorter workdays:
There is clear evidence that a reduction of workday to 6 hours benefits work performance. This could be due to many complex, pyscho-social factors.

There are some company-based interventions that have studied the effects of a reduction in workhours from 7 or more to 6 hours. In an intervention study among female health care workers, a decrease in workhours (to a 6-hour workday) resulted in improvements in the social life of the workers and in moderate improvements in well-being when the group was compared with a reference group with no changes in workhours. In another study, a shift to 6-hour workdays was followed by a reduction of neck-shoulder and back pain in three separate organizations when fulltime payment of the workers was retained.
  According to Anttila, the benefits of shorter workhours were the most apparent in regard to social life, but they also introduced some positive effects on the perceived stress of the workers ...

Scand J Work Environ Health 2006;32(6, special issue):502-514
Workhours in relation to work stress, recovery and health
by Mikko Harma, MD
Physical effect of shorter workday:

The shortening of regular workdays from >7 hours to 6 hours may considerably reduce the
  prevalence of neck-shoulder pain among persons with physically demanding care work. The potential health
  benefits should encourage intervention studies also in other occupations with increased risk of work-related
  musculoskeletal disorders.

A shorter workday as a means of reducing the occurrence of
musculoskeletal disorders
by Ebba L Wergeland, PhD, et al Scand J Work Environ Health 2003;29(1):27-34
As @Jens noted in Ericsson's study.

best students practiced on average 3.5 hr per day

This, along with the evidence about attention and circadian rhythms, perhaps, suggests that this is an optimal time for mental acuity. (not taking into consideration the physical restraints of finger strain on violinists).
The double peak of alertness within the circadian cycle gives credence to the notion of a "siesta" of prolonged, daily work break, to boost productivity, but this argument is not as straightforward as it may seem on the surface.

Studies which may be helpful:
This  study 15 Indus. & Lab. Rel. Rev. 307 (1961-1962)  Shorter Hours - In Theory and Practice; Dankert, Clyde E. gives detailed analysis, where output optimum is examined and optimum working day and optimum working week evaluated.
Orthostatic symptoms, blood pressure and working postures of factory and service workers over an observed workday
Suzy Ngomoa, et al doi.org/10.1016/j.apergo.2007.11.004
I do not have access to these articles

Associated References:
A META-ANALYSIS OF WORK DEMAND STRESSORS AND JOB PERFORMANCE: EXAMINING MAIN AND MODERATING EFFECTS
SIMONA GILBOA1, ARIE SHIROM1, YITZHAK FRIED2, CARY COOPER3
DOI: 10.1111/j.1744-6570.2008.00113.x
Extended workdays: Effects on performance
and ratings offatigue and alertness ROGER R. ROSA DANIEL D. WHEELER and JOEL S. WARM MICHAEL J. COLLIGAN
CIRCADIAN RHYTHMS OF PERFORMANCE: NEW TRENDS
2000, Vol. 17, No. 6 , Pages 719-732
Julie Carrier1,2 and Timothy H. Monk3
doi/abs/10.1081/CBI-100102108
Carrier, J., & Monk, T. H. (2000). Circadian rhythms of performance: New trends.
Chronobiology International, 17, 719–732. doi:10.1081/CBI-100102108.
Schmidt, C., Collette, C., Cajochen, C., & Peigneux, P. (2007). A time to think: Circadian
rhythms in human cognition.Cognitive Neuropsychology,24, 755–789.doi:10.1080/
02643290701754158
Health effects of shift work and extended hours of work
J M Harrington
Adverse changes in mood and cognitive performance of house officers after night duty.
D. I. Orton and J. H. Gruzelier
Extended workdays: Effects of 8-hour and 12-hour rotating shift schedules on performance, subjective alertness, sleep patterns, and psychosocial variables
DOI:10.1080/02678378908256877
Roger R. Rosaa, Michael J. Colligana & Paul Lewisb
Professor Cary Cooper CBE publications
Changes in Electromyographic Activity Associated with Occupational Stress and Poor Performance in the Workplace
Frank E. Gomer
Behavioral Science Applications, Yellow Springs, Ohio
Louis D. Silverstein
Sperry Corporation, Phoenix, Arizona
W. Keith Berg
University of Florida, Gainesville, Florida
Donald L. Lassiter
Georgia Institute of Technology, Atlanta, Georgia
Job content and working time: the scope for joint change DOI:10.1080/00140139108967349
KAZUTAKA KOGIa
IS PART-TIME EMPLOYMENT BENEFICIAL FOR FIRM PRODUCTIVITY?
Annemarie Nelen, Andries De Gripa, Didier Fouarge

Note:
There is much anecdotal evidence of professional working 4 or 5 hour days to maximise their performance; one example being an author writing a book.


text:
Are there benefits to learning to write with your non-dominant hand?
There are some articles on the web that recommend learning to write with your non-dominant hand to get in touch with your inner child or a higher power, increase your creativity and be more open-minded or some such thing. I don't usually believe random stuff from the internet, but:
One of my drawing teachers told us to try drawing with the non-dominant hand. What I discovered was that I was very much better at getting proportions right with the non-dominant hand. I only had to use the dominant hand to clean up the shaky lines, because my non-dominant hand has poor fine motor control.
So there is obviously something that happens, when I use the "other" hand, something that has to do with how my perceptions are processed and my hand movement is controlled. But these "switches" while I draw are just temporary. What is sometimes recommended on some websites is a more fundamental change: to switch hands for all tasks.
Is there research on the effects of switching hands for all or certain tasks?
I have no idea which tags I should select. Please edit my tags, if you feel you know better.

Yes, there are benefits, but I don't think it requires long-term switches.  Studies have used this as a manipulation to try and increase self control and have found that it decrease aggression.  Based on this, once one has mastered using the non-dominant hand, it seems like the benefit of continuing to use that hand might be over (as it no longer requires effort).
See: Denson, T. F., Capper, M. M., Oaten, M., Friese, M., & Schofield, T. P. (2011). Self-control training decreases aggression in response to provocation in aggressive individuals. Journal of Research in Personality, 45(2), 252–256. doi:10.1016/j.jrp.2011.02.001

"Our findings provide evidence for persisting differences in the functional neuroanatomy of handwriting between right-handers and converted left-handers, despite decades of right-hand writing." http://www.jneurosci.org/content/22/7/2816.long The brains of converted left-handers are more active than non-converted right- or left-handers, and they are active in a "left-hand way": "brain regions involved in planning movement stubbornly refuse to switch, and continue to act like those of left-handers in people who have switched to right-handedness". http://www.jneurosci.org/content/27/29/7847.full

+1 for the the new info -- didn't know this was used as a manipulation. Very interesting. But it seems like some differences persist, though it apparently remains unclear what effects these differences have.

https://www.dailymail.co.uk/sciencetech/article-3820189/Could-forcing-write-hands-make-smarter-Experts-remain-divided-bizarre-brain-training-technique.html

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text:
The genetics of handedness
In response to these questions:
Are there benefits to learning to write with your non-dominant hand?
Spontaneous change of handedness
I used myself as an example for spontaneous handedness change.

Example:
I began as a left hander. I spontaneously changed to a semi-ambidextrous right hander.
Two of my three children are true left handers, the other is a true right hander (their father and his family are all right handed).
My parents and siblings are right handed.
 My maternal grandmother was ambidextrous.

Question:
What are the genetics of handedness?

http://en.wikipedia.org/wiki/Handedness#Genetic_factors

There appears to be a higher correlation with environmental influences affecting handedness, as opposed to the genetic factors; although there is conclusive genetic evidence, it is not the major contributing factor in determining handedness.
I quote from the link @what provided in the comments.

Handedness displays a complex inheritance pattern. For example, if
  both parents of a child are left-handed, there is a 26% chance of that
  child also being left-handed.[8] A large study of twins from 25,732
  families by Medland et al. (2006) has indicated that the heritability
  of handedness is roughly 24%.[9] This leaves about three quarters of
  the effect to be explained by environmental factors.
To date, two theoretical single gene models have been proposed to
  explain the patterns of inheritance of handedness, the first by Dr.
  Marian Annett[10] of the University of Leicester and the second by
  Professor Chris McManus[8] of UCL.
Both models propose that there is a variant in a single gene that has
  two alleles. Carriers of one allele are more likely to be
  right-handed, and the other allele does not specify the direction of
  handedness, instead leaving it to chance. They differ on the precise
  effect of the 'right-shift' allele, but both models provide similar
  fits to data on the inheritance of handedness. Oxford University
  psychiatrist Professor Tim Crow has taken the single-gene model one
  step further, and proposed that mutations in the gene PCDH11X were
  responsible for the evolution of handedness, cerebral asymmetry,
  language, susceptibility to schizophrenia, and was the speciation
  event that created Homo sapiens.[11]
Although single-gene models can be fitted to the data, a number of
  genetic linkage studies have been performed, all of which have
  provided evidence for different regions of the genome contributing to
  variation in handedness.[12][13] [14][15] Only one of these studies
  has led to the identification of a specific gene that is proposed to
  contribute to variation in handedness. [16][17]
Medland et al.[18] found a gene that is positively correlated with
  left-handedness in females, and negatively correlated in males. This
  may help to explain why there are more left-handed men than women
  (around 12% in men versus 10% in women globally).3

It is, also, important to define handedness, or types of handedness, and the variability between self-reporting and objective evidence.

However, genes influencing sidedness remain elusive. We measured
  direction and consistency of hand, foot, and eye preference in 584
  Mexican-Americans from families participating in the San Antonio
  Family Diabetes/Gallbladder Study. Using maximum-likelihood-based
  variance components methods, we estimated weak (.11 ≤ h2≤.17) but
  significant heritability for foot preference, eye preference, several
  hand preferences (writing, drawing, throwing, using scissors, using
  spoon, striking match), and a composite hand preference trait.
  Self-reported handedness was significantly heritable (h2=.57), whereas
  hand preference for opening a box or using a toothbrush or knife was
  not. Many trait pairs had significant genetic correlations, and all
  had significant environmental correlations.

(Heritability and linkage analysis of hand, foot, and eye preference in Mexican Americans  Diane M. Warrena*, Michael Sternb, Ravindranath Duggiralac, Thomas D. Dyerc & Laura Almasyc   DOI:10.1080/13576500600761056)
There is also the concept that handedness is on a continuum and that there is not, necessarily, a definitive left or right handedness, bit rather where the individual sits on the contiuum of cerebral dominance. This study also examines  the genetic modelling versus the environmental factors, and the unreliability of self-reporting. It also, introduces the idea the people may under-report left handedness. This also demonstrates that left handedness is inherited maternally.

Whereas many assume there is a true incidence of left-handedness, the
  RS theory suggests that degrees of hand preference map onto a
  continuous baseline of asymmetry that can be cut at any point to
  represent observed incidences of left-handedness. The parameters of
  the RS genetic model were derived from findings for speech
  lateralization in aphasics, supporting the argument that the relevant
  genetic locus is “for” cerebral dominance, not handedness. Genetic
  predictions are given for two levels of parental left-handedness (10%
  and 20%). Studies of family handedness distinguishing for sex in both
  generations gave generally good fits where handedness was assessed by
  self-report, but more variable fits for indirect report of relatives'
  handedness. The tendency to find a higher proportion of left-handed
  children born to left-handed mothers than left-handed fathers is not
  likely due to X-linked inheritance, but rather to slightly stronger
  expression of the RS+ gene in females than males, and also
  under-reporting of left-handedness in mothers by right-handed
  children.

(The genetic basis of lateralization Marian Annett dx.doi.org/10.1017/CBO9780511576744.006)
There has been research demonstrating that the LLRTM1 gene contributes to handedness. This gene has also been linked with increased incidence of schizophrenia. An interesting observation, given the historic "demonisation" of left handers. Could this be, because there was a perceivable  increased incidence of "insanity" amongst the left handers? (note, my own theory)

Left-right asymmetrical brain function underlies much of human
  cognition, behavior and emotion. Abnormalities of cerebral asymmetry
  are associated with schizophrenia and other neuropsychiatric
  disorders.....    This is the first potential genetic influence on
  human handedness to be identified, and the first putative genetic
  effect on variability in human brain asymmetry. LRRTM1 is a candidate
  gene for involvement in several common neurodevelopmental disorders,
  and may have played a role in human cognitive and behavioral
  evolution.

LRRTM1 on chromosome 2p12 is a maternally suppressed gene that is associated paternally with handedness and schizophrenia. Francks C, et al.

So, given my example, it is not surprising that:

The left handed family members were all on the maternal side.
The incidence of left handedness was low.

+1 for including the information about different types of lateralization preferences (using scissors, throwing, foot preference, etc.) -- "handedness" is a big oversimplification

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text:
Failing to recognise one's own work
Disclaimer:
This is not a self help question, I am using myself as an example to illustrate my question.

Example:
I have posted many questions and answers on this site within a relatively short time. Frequently (and with my blessing) our Mod Jeromy will edit my question titles. He does not edit all of the titles.
I find myself browsing through the site, looking to upvote older questions, looking for unanswered questions. Sometimes (and too often) I come across a question and think, that's interesting, only to realise I posted the question. I do this with answers also. I think that's interesting and see I've posted it.

I can surmise, it is because of the sheer volume, perhaps stress and the inability to process memory.  I am wondering if this is a known condition.
Question:
What causes this phenomena of failing to recognise one's own work?
Is it a recognised condition?
Which part of our brain is responsible for this?

I accidently reach my own StackOverflow questions from Google as they show up first in the results. When I encounter my own post, I can appreciate and like the (my own)style long before I recall the existence of that post. Does this seem a sufficient explanation for your case?

I would like to add a bit of terminology to @what's answer. Of course memory is a pretty big topic with different and sometimes conflicting theories and I would not consider myself an expert. Having this said, the distinction between Long Term Memory (LTM) and Working Memory is widely used, so I will use it, too.
The problem that you describe in your question refers to LTM. Even if @what does not actually use the term LTM in his answer, everything he says does refer to LTM. Furthermore he refers to two procceses that play a role in memory: encoding and retrieval.
Encoding vs. Retrieval
Encoding is the process of getting something from Working Memory into LTM. A stimulus is not remembered "as is", but rather it is processed. It might, for instance, be perceived as belonging to a certain category or it might have a strong emotional value (as @what suggested). This opens the door for quite a few theories of why some things are remembered better or faster than others.
Retrieval is the process of getting something from LTM back into Working Memory, so that it can be used there. It is possible that one has something in LTM, but for some reason is not able to retrieve it. (In fact, it has been said that we don't actually forget things, but there are things that we cannot retrieve, as @what said.)
LTM vs. Working Memory
To get back to your question: Not being able to recognise something might be because of either one of those things. Either there was a problem with encoding, or there is/was a problem with retrieving. In any case, in my opinion it is not possible to explain this phenomenon using the concept of Working Memory, as you did in your answer.

+1 Great supplement, Jens. This actually motivates me to dig into the literature and find some research on forgetting. Maybe I'll do that in a month, when I have more time.

I'm using your example, because another example would lead to a different interpretation. Using your example is not meant to help you, just to illustrate my answer.
The normal situation is to forget things. There are people who dispute this, believing that you store any and all information you ever encountered (after all, what would the famous 90% unused brain be for?), but from a more scientific perspective, most of the info that goes into your sensorium is simply lost after it was used. Because you don't need to remember the color of the car that just passed.
So the question is, why and when do we actually store stuff in our memories? Short answer: when it appears important. Usually, because it is connected to an emotion. If you care about something, you remember it, if you don't, you won't. This does not mean that you only forget stuff that is unimportant, though. If you are stressed or distracted, important things are momentarily unimportant.
Interpreting your example from this perspective, we could infer that you did not much care about those questions you wrote, at least not individually, because you asked them for other purposes (passing the time, gaining reputation, socializing in a community), or that you have other more important stuff going on in your life and that you ask questions here as a distraction, while part of your mind is still elsewhere.
But then, there is another phenomenon: If you have a thought and want to remember it, it blocks your mind. I'm sure you have noticed how trying not to forget the great sentence that you want to begin your next novel with keeps you from having any other ideas. That's why writers carry notebooks: they jot down the sentence, and immediately forget it, freeing their minds to new ideas.
So when you write your question here, you are actually telling your mind: "Okay, that's done, now let's think of something else." And your mind complies, discards that idea, and starts thinking of other things, forgetting any former thoughts.

I agree with @what. I was going to edit his answer, but thought it would be better to post this as an adjunct to his answer.
Disclaimer:
The conclusions I have drawn here are my own ideas.
For individuals who are in the full-time occupation of deep concentration, through work, study, interests, their working memory is getting very little downtime.

Working memory is your brain's Post-it note, says Tracy Packiam
  Alloway, PhD, assistant professor of psychology at the University of
  North Florida in Jacksonville, Florida. “It makes all the difference
  to successful learning,” she says.
You can think of working memory as the active part of your memory
  system. It's like mental juggling, says H. Lee Swanson, PhD,
  distinguished professor of education with the Graduate School of
  Education at the University of California, Riverside. “As information
  comes in, you're processing it at the same time as you store it,” he
  says. A child uses this skill when doing math calculations or
  listening to a story, for example. She has to hold onto the numbers
  while working with them. Or, she needs to remember the sequence of
  events and also think of what the story is about, says Swanson.
Brief by design, working memory involves a short-term use of memory
  and attention, adds Matthew Cruger, PhD, neuropsychologist with the
  Learning and Diagnostics Center at the Child Mind Institute in New
  York City. “It is a set of skills that helps us keep information in
  mind while using that information to complete a task or execute a
  challenge,” he says. Working memory is like a foundation of the
  brain's executive function. This is a broad and deep group of mental
  processes. They allow you to do things like plan ahead, problem solve,
  organize and pay attention.1
“Working memory helps us stay involved in something longer and keep
  more things in mind while approaching a task,” says Cruger. “And, how
  can you plan ahead if you don't use working memory to keep your goal
  in mind, resist distractions and inhibit impulsive choices?”

(What Is Working Memory and Why Does It Matter? By Annie Stuart)
An individual engrossed in mental tasks is going to be coming in and out of states where the working memory is, potentially, overloaded. So, for instance, coming to a site like this, may serve as a distraction from learning or working (This answer discusses the value of distraction as beneficial to work productivity); however a great deal of  attention is required to focus effectively on the site.
So if an individual chooses a mentally demanding "distraction" (as in this example posting on a Cognitive Sciences site; for others it may be another form of intellectual hobby), they are flitting from one state of deep concentration, with an occupied working memory, to another. I would suggest that the focus upon one mentally demanding task and an alternate, less mentally consuming, distraction task would alleviate this overload.

The term working memory refers to a brain system that provides
  temporary storage and manipulation of the information necessary for
  such complex cognitive tasks as language comprehension, learning, and
  reasoning. This definition has evolved from the concept of a unitary
  short-term memory system. Working memory has been found to require the
  simultaneous storage and processing of information. It can be divided
  into the following three subcomponents: (i) the central executive,
  which is assumed to be an attentional-controlling system, is important
  in skills such as chess playing and is particularly susceptible to the
  effects of Alzheimer's disease; ....

(Working memory. Baddeley A.)
Although working memory itself, is not the same as long term memory, I am suggesting that an overloaded working memory, would interfere with the ability to multi task from one mentally demanding task to another completely different mentally demanding task.
This does not touch upon the effects of stress on memory, nor does it discuss the effects of attention on memory, as I think the notion of working memory being in a constant overloaded state would explain this phenomena.
Edit:
After feedback, I would like to make my point clearer.

I am proposing that a working memory, that is being fully utilised, is not so easy to "clear" to create a concentrated focus on another mentally consuming task.
I have stated clearly that WM is different to long term memory (which stores the memory)
I am suggesting (if the problem isn't the actual storage of the memory, ie within long term memory) and given the description of the problem, that it could be the limitations of working memory.

Hmm, I am afraid this is not an answer to your question. See my answer for an explanation.

+1 Great idea. Maybe we can find something on working memory and forgetting and how exhaustion plays a role.


text:
The relationship between working memory and emotion
I stumbled up on this article about working memory.
Within a table of indicators of good or poor working memory, it listed the following for adult working memory:

Indicators that a working memory needs exercise

Frequently late to work
Often underestimates time required for a
task
Has problems breaking a project into manageable steps
Often
loses temper with children and spouse

It is the last point:

Often loses temper with children and spouse

This brings me to the question:
Are there  studies examining the relationship between working memory and emotion?
If so what are the results?

Working memory and other aspects of executive function (attention, for instance) are linked. There is evidence that improving self control improves emotional outbursts (see article below).  So, improving working memory should improve self control, which should prevent emotional outbursts.
See: Denson, T. F., Capper, M. M., Oaten, M., Friese, M., & Schofield, T. P. (2011). Self-control training decreases aggression in response to provocation in aggressive individuals. Journal of Research in Personality, 45(2), 252–256. doi:10.1016/j.jrp.2011.02.001

My husband and I have Traumatic Brain Injury and Cognitive difficulties. All of the points above describe us. The most difficult obstacle is the last, loosing temper with spouse.  The statistics state "that in a marriage where one partner receives TBI  80% of them fail. When both are involved it is said they physically hurt or kill each other. Six years into the TBI we still struggle.
Emotions and memory are both disturbed when the Frontal lobe is damaged. Therefore both working memory and emotions are related by their location. If a person has a deficit in working memory they are easily agitated and therefor emotional. Assuming you are only considering the loss of temper emotion that would be disrupted by lack of memory. You also only point out children and spouse which are most often the target of a familiar relationship and therefor spend much time in each others presence. A reminder of the retirement syndrome, where age creates memory difficulties and stresses a relationship due to 24/7 time on hands and usually spent with those mentioned. Fact is I can blame my memory difficulties on age. Emotions are generated by unhappiness and memory,or loss of,creates unhappiness. Executive functions are stored closely and related by area and therefor improving one of either would improve the other by definition of the area stored and malfunction in either or that area. There are other characteristics like retention for instance that may cause some of the points noted and time management or staying on task also apathy which may case " who gives a care" at the moment.  This is my hypothesis.


text:
Lecture versus problem-based learning of psychology
Studying psychology at a German university, the first two years of your curriculum will be almost entirely filled with lectures: students sit in an auditorium, listen to the professor talk for 90 minutes, they take notes, read a book or two, memorize as much of the content of lecture and books as they can, and at the end of the semester they take an exam. There are six to eight lectures per week, adding up to 12 to 14 hours, and there are an equal number of exams, adding up to the same number of hours.
From my experience and from talking to fellow students, I have the impression that we don't learn much in this way. We call it "bulimic learning": eating up huge amounts of information in a short span of time, barfing it up during the exams, and then immediately wiping our minds of it to hurriedly fill it up again for the next test. This feeling of not learning much is not wholly subjective: a large part of the early education is methodological, and the superficial and incomplete understanding of this area becomes painfully apparent once we have to apply it in more practical seminars. Most of us have to look up even basic statistical procedures that we had to know to pass our tests.
Talking to the professors that teach these courses, the replied to my critique of the current system with pointing out that there are a hundred to two hundred students visiting each lecture, and that it would be impossible to teach them in any other manner. I am not convinced of this. Other disciplines, for example in the humanities, manage the same ratio of students per professors only with seminars, none of which have more than 30 students, and completely without lectures.
Science – and I mean all science –, in my opinion, is a practically applied occupation. Even a practitioner of a more theoretical field, like metaphysics or theoretical mathematics, creates new ideas, "experiments" with them, and writes a paper about them. There is no creativity and nothing practical in learning for an exam, while there is no science that you cannot teach in an applied manner, if you are willing to be less normative about what students need to know: let them find their own problems, their own literature, their own ideas, and present them, discuss them, and revise them. Just as they would do as graduated scholars and researchers.
In a review of studies comparing problem-based learning, with learners "actively elaborating their conceptual frameworks", and traditional teaching through lectures, Reynolds (1997) found that problem-based learning "encourages deep rather than shallow strategies of learning", while "students who followed a traditional curriculum ... manifested poorer learning strategies which favoured reproducing information, with less attention to personal comprehension". Additionally, "PBL courses tend to be associated with better attendance and less distress and depression". Results regarding the increase in knowledge appears to be contradictory, however.
I wonder if there is more (and more recent) research on different methods of teaching psychology, or on the relative merits of lecture versus seminar style teaching, in or outside of psychology.

Sources:

Reynolds, F. (1997). Studying psychology at degree level: Would problem-based learning enhance students' experience? Studies in Higher Education, 22, 263-275. doi:10.1080/03075079712331380886

Note the "less distress and depression" in my question. A fellow student likened studying psychology to the degrading initiation rites of some primitive cultures and the basic training of the military: you have to suffer through the old men making you want to die, before you can become one of them.

Sure seems like there ought to be something...Wish I knew more about educational psychology in general...

There is a large amount of research of research that compares the effectiveness of problem based learning (PBL) with more traditional approaches such as lectures. Most of it stems from medical science education, and attests to the positive consequences of PBL (see the meta-analysis by Walker & Leary, 2009). However, some researchers have questioned how rigorous this research is and others have doubts whether the benefits of PBL are worth its costs - as it can be quite resource demanding (for a starting point into this discussion and literature, see e.g., Pease & Kuhn, 2011).
Furthermore, there seems to be much heterogeneity in the effectiveness of PBL (e.g., Walker & Leary, 2009). Several meta-analyses have been conducted in an effort to explain these differences. A good starting point into the subject may be Strobel and van Barneveld's (2009) meta-review of PBL-meta analyses. Quoting from their abstract:

Problem-based learning (PBL) has been utilized for over 40 years in a
  variety of different disciplines. Although extensively researched,
  there is heated debate about the effectiveness of PBL. Several
  meta-analyses were conducted that provided a synthesis of the effects
  of PBL in comparison to traditional forms of instruction. This study
  used a qualitative meta-synthesis approach to compare and contrast the
  assumptions and findings of the meta-analytical research on the
  effectiveness of PBL. Findings indicated that PBL was superior when it
  comes to long-term retention, skill development and satisfaction of
  students and teachers, while traditional approaches were more
  effective for short-term retention as measured by standardized board
  exams.

[emphasis added]
If you are looking for research on PBL in psychology, the journal Teaching in Psychology may be worth a look. The journal is more of an outlet for publications on specific exercises and teaching-related resources ("hands-on-approach"). However, the proposed teaching methods and exercises (which could be often regarded as PBL) are usually compared to traditional approaches in small evaluation studies. Other than that there doesn't seem to be much research that looks into the effectiveness of PBL in psychology on a broader level.
References
Pease, M. A., & Kuhn, D. (2011). Experimental analysis of the effective components of problem-based learning. Science Education, 95, 57–86. doi:10.1002/sce.20412
Strobel, J. , & van Barneveld, A. (2009). When is PBL More Effective? A Meta-synthesis of Meta-analyses Comparing PBL to Conventional Classrooms. Interdisciplinary Journal of Problem-Based Learning, 3(1).
Walker, A. & Leary, H. (2009). A Problem Based Learning Meta Analysis: Differences Across Problem Types, Implementation Types, Disciplines, and Assessment Levels. Interdisciplinary Journal of Problem-based Learning, 3(1), 6-28.

I completely agree with you that psychology could be taught in much better ways. However, teaching just about any science in the way that you are wanting is a lot harder than you might think. It can't be compared to the humanities.
You are correct that all science is a practice and that you learn to be a practitioner through solving problems and receiving feedback. However, in science there is a massive overhead cost before one can actually work with the material. I got my undergraduate education in psychology by spending 10-20 hours/week in a lab for four years... THEN I was ready for graduate school. The courses were great to get my imagination going, but the lab was an absolute necessity. Learning any science means learning a lot of boring (and I mean REALLY boring) skills, most of which are entirely useless outside the field. Many times we learn a particular skill just to run a single study, then never use it again.
To do a single study in psychology takes a really long time. Participants have to be recruited, computer apps need to be programmed, teams of RAs need to be coordinated and trained, procedures need to be planned and tested and revised and tested..., etc.
To be clear, I'm not saying that the way we teach psychology at the undergraduate level is adequate. What I'm saying is that the optimal way to teach psychology would require a massive (read: expensive) overhaul to the system and ratios of students to professors that are not feasible. I think psychology is taught the way it is because it exposes people to the different topics with the hope that some of the useful information will be retained. For students who really like psychology, the assumption is that they will seek out their own education in psychology by finding a professor to work with. If your concern is just at the conceptual level, then I agree with you and I wish we could do more. However, if your concern is practical and you want an education in psychology, your only real option is to start devoting 40-80 hours per month working on 1-on-1 with a professor (or grad student) on a project.

CogSci encourages answers based on facts, references, or specific expertise, and this may (or may not) be a question that calls for specific expertise. The answer is consistent with my own views, but I'm leery of upvoting it because it is essentially unsubstantiated. In other words, I'm not sure someone with a different prior view (e.g., @what) would find this convincing without knowing what your specific expertise is.

I understand the problems with my answer from an academic perspective. However, the original question seemed heavily motivated by criticism that psychology hasn't adopted some form of PBL. Whether PBL works for  psychology seemed less relevant to the topic compared to why it isn't used. Hopefully nobody puts too much weight on my answer.

I completely understand. Sorry about the curtness. I don't mean to be adversarial, I just often run out of characters. It's a good answer, just not one I would find convincing if I didn't already agree with it (if that makes sense).

Adversarial and critical aren't necessarily the same thing :). Its clear that your comment was well-intended and it points out that my answer isn't up to empirical standards. Unfortunately, when it comes to the way that academic institutions make decisions and how it impacts something as specific and long-term as teaching students how to conduct a science, we probably just don't have the data to say much with any certainty (as MariaAnt acknowledges above)


text:
Why does strobe lighting trigger seizures in photosensitive epilepsy?

Photosensitive epilepsy (PSE) is a form of epilepsy in which seizures are triggered by visual stimuli that form patterns in time or space, such as flashing lights, bold, regular patterns, or regular moving patterns.

Why does strobe lighting trigger seizures in photosensitive epilepsy?

Pulsating visual stimuli can cause steady state visually evoked potentials, that is, brain oscillations with a frequency matching the visual stimulation: http://en.wikipedia.org/wiki/Steady_state_visually_evoked_potential. I would guess that these evoked oscillations are the cause for the seizure.

@H.Muster: I think you are right. I think that epilepsy can be described as strong coupling of oscillations across large portions of the brain, and these may be triggered by oscillatory stimuli.

Seizures induced by stroboscopic lights are an example of reflex seizures. This type of epilepsy includes seizures evoked by touch and movements as well. The mechanism behind generalized reflex seizures (generalized epilepsy, as opposed to partial epilepsies, is accompanied by a loss of consciousness) was abstracted nicely by Ferlazzo et al., 2005:

Patients with [] generalized reflex seizures appear to have regions of cortical hyperexcitability overlapping or coinciding with areas physiologically activated
  during specific sensory stimulations and cognitive or motor activities. When these areas receive appropriate afferent volleys and a critical mass of cortex is activated, an epileptic activity is produced that ultimately involves cortico-reticular or cortico-cortical pathways resulting in a generalized or bilateral epileptic event.

In other words, stimuli such as stroboscopic light evoke activity in sensory cortex. If the area of excitation is large enough and occurs in a region of the brain that has an epileptic focus (hyperexcitable cortex) than it may trigger a seizure characterized by an uncontrolled wave of activity spreading across the cortex.
Specifically for flashing-light induced seizures it is thought that seizures start in the visual cortex in the occipital lobe due to impaired cortical mechanisms of contrast gain control for certain visual patterns, producing an abnormal excitatory response to patterns of relatively low temporal frequency and high luminance contrast. Specifically, the seizures may be caused by a loss of control over high-frequency oscillatory processes that normally operate transiently to connect the involved neural assemblies. Generalized seizures can occur if normal excitation of visual cortex involves a ‘critical mass’ of synchronized activity in a cortical area with synchronization and subsequent spreading of excitation from the occipital lobe trigger zone (Parra et al., 2005).
References
- Ferlazzo et al., Brain (2005); 128: 700–10
- Parra et al., Curr Opin Neurol (2005); 18(2):155-9


text:
How does chronic stress improve memory processes?
There seems to be more information on the detrimental effects of stress on memory.
There is evidence to the contrary.
Stress effects on memory: an update and integration.
Schwabe L, et al  doi: 10.1016/j.neubiorev.2011.07.002

It is well known that stressful experiences may affect learning and memory processes. Less clear is the exact nature of these stress effects on memory: both enhancing and impairing effects have been reported.

I am interested in the research available on stress positively effecting memory.
What are the biological reasons for stress enhancing memory processes?
There is a related question Can the brain work better in stressful conditions?; I am interested more in chronic stress. An examination of the effects of acute stress on memory, I believe, warrants a separate discussion.

Interesting question. Intuitively, I would have thought that chronic stress would uncompromisingly be a detriment to our memory and recall.
An article by Ohira et al (2011) makes note that it is accepted that chronic stress is seen to adversely affect memory, it may not be replicated in other studies:

"However, results related to the effects of chronic job stress
  and cognitive functions remain controversial. Although
  chronic job stress is generally linked to reduced memory
  and learning (Holman and Wall, 2002; Taris and Feij,
  2004), a recent epidemiological study with a larger sample
  size failed to replicate these effects (Elovainio et al., 2009)."

Other studies may indicate that predictable chronic mild stress can improve hippocampal neurogenesis and memory (Parihar et al., 2011). Your question doesn't describe the level of stress experienced as a variable so broadly, this article might be very relevant:

"Furthermore, enrichments in mood and memory after PCMS were
  associated with substantially increased hippocampal neurogenesis ...
  The overall stress reaction in an organism can be advantageous for
  cognitive functions when it induces moderate increases in
  corticosterone levels and leads to adaptation and resistance ... The
  PCMS regimen used in this study likely elicited moderate increases in
  corticosterone levels, which facilitated adaptive and beneficial
  responses in the brain."

It's implied that unpredictable chronic stress would have a detrimental effect on memory. Some of the biological reasons for enhancing memory processes are presented in that above study.
EDIT: Additional Information
Also see - McFadden, L.M., Paris, J.J., Mitzelfelt, M.S., McDonough, S., Frye, C.A. & Matuszewich, L. (2011). Sex-dependent effects of chronic unpredictable stress in the water maze. Physiology & Behavior, 102(3), 266-275. The research conversely highlights that unpredictable stress improves performance on a spatial memory task in female rats.
References

Ohira, H., Matsunga, M., Kumra, K., Murakami, H., Osumi., T., Isowa, T., Fukuyama, S., Shinoda, J. & Yamada, J. (2011). Chronic stress modulates neural and cardiovascular responses during reversal learning. Neuroscience, 193, 193-204
Parihar, VK., Hattiangady, B., Kuruba, R., Shuai, B. & Shetty, AK. (2011). Predictable chronic mild stress improves mood, hippocampal neurogenesis and memory. Molecular Psychiatry, 16, 171-183

No problems, ThinksALot.

I've added another reference that is relevant to your question.


text:
Dreams and sleep phases, and duration of dreams
Supposedly, people mainly dream during REM sleep, and dreams last up to 20 minutes (see for example the first paragraphs of the Wikipedia article on Dreams).
My subjective experience differs:

No matter at what time I awake, I always awake from a dream.
And since I often awake not on my own (during phases of light sleep) but because I'm disturbed by outside noises (the crying baby of our neighbors, car doors slamming), and often feel groggy and disoriented upon awakening, I probably often awake from deep phases of non-REM sleep. Still, I always awake from a dream.
When I wake up I often remember an unbroken storyline from the last thoughts before I fell asleep until the moment of awakening.So obviously my dreams must have continued for hours – either in an unbroken stream or by taking up after a break where the story was "paused" before it.

Are there recent theories or research findings that explain this subjective experience?

I also don't observe the conventional simple scenario.  I'll nod off for a moment and wake fro a dream, meaning I was dreaming immediately. That implies nom-REM drwaming or jumping directly to the REM phase, either of whichnis against the script.

Related: https://cogsci.stackexchange.com/q/8386/7001 and https://cogsci.stackexchange.com/q/7948/7001

I don't think what you're describing is that unusual. I read about dreams and dreaming in Jaak Panksepp's "Affective Neuroscience" some years ago, and here is what I remember:
First, it is not entirely accurate to say that dreams happen only during REM sleep. What is unique to REM dreams is visual imagery. NREM sleep, also called slow wave sleep, also contains dreams, but they are just a series of thoughts - not very different from when you think about things while awake.
Second, even if you are describing visual dreams: REM sleep is more shallow than slow wave sleep, i.e. outside noises will wake you up more easily than during the other sleep stages.
Third, it's very standard to dream about things that are currently going on in your life.
Fourth, dreams are extremely fragile, they evaporate from memory very quickly unless you actively do something mental with them, and it is easy confabulate some new details into them while trying to keep them from slipping away. It could be that you are reconstructing the content or duration of your dreams a little bit while you are trying to compare them to your thoughts before sleep.

Thank you! Let me elaborate: When you are awake, your thoughts form an unbroken sequence. You are unable to remember or recreate the whole sequence of thought from getting up to going to bed, nevertheless you know of this unbroken sequence, because you experience it and at each moment you are aware of this sequential aspect of your thoughts: you know the last few thoughts before the current one and could backtrack. Always. There is never a break without any thought. I experience my dreams in the same way. While I dream, I am consciously aware that I dream and observing my dreams. [contd.]

[contd.] I usually forget them as they pass, but I observe their sequentiality. I see how the "story" begins as I "go under" and continues until I wake up. I experience how one "event" evolves from the preceding. I rarely remember anything from my dreams for longer than a few seconds after waking up, but I remember the observation of continuity.


text:
Why do people remember things when they stop trying to remember?
I posted this question on SE English:
Antonym for ameliorate
I had been trying to recall a word and it's recollection kept evading me.
I remembered the word as soon as I posted the question; which was when I gave up trying to recall it.
What is the scientific term and process by where a person cannot recall something and then remembers it when they stop trying?


text:
Why do people get syllables mixed up when trying to recall words?
This question is related to this question. It could be a dupe, but I am more interested in whether this is a form of "dyslexic" thinking (for want of a better expression)?
I posted this question on SE English:
Antonym for ameliorate
Where I could not recall the word deleterious and was remembering it as: detiliorate (a non-existent word). I was miss remembering the order of the syllables. plus some other confusion.

I was confusing the de-le-terious with de-ti-liorate, that is, I had inverted the "L" and "T" sounds in the syllables.

Why do people tend to get sounds mixed up in this way?
What is the process behind this?

One way of thinking about speech production is using a spreading activation architecture. Say I want to produce the word "rooster." I have a meaning to be expressed (feathery avian animal loud...etc). These semantic representations send activation down to various matching words (bird, rooster, chicken...etc). As these words collect evidence for themselves, they send activation down to their corresponding sounds (bird sends activation to the sounds /b/, /r/, and /d/; rooster sends activation to /r/, /u/, /s/, /t/ ..etc). Once any node (word, sound..etc) receives enough evidence for itself, it is selected. There are nuances about how and when nodes become selected and how activation is passed, but this is the gist. In addition, there is noise in the system based on words that were previously said, upcoming words, words that are semantically related and so on.  This noise introduces the possibility for speech errors. Some errors are more likely than others depending on the amount of evidence they have collected. For example, in the example I presented here, the /r/ sound got more activation than the other sounds because it is collecting activation because it appears once in the word 'bird' and twice in the word 'rooster.' This sound might be more or less likely to be produced erroneously compared to sounds like /s/. These error probabilities explain why we are more likely to make real word errors, and why tongue twisters are so tricky. See the following article for more information.
Dell, G. S. (1986). A spreading-activation theory of retrieval in sentence production. Psychological review, 93(3), 283.

Interesting theory. To apply it to the OP's specific issue, would you propose that familiarity with "ameliorate" led to over-activation (or an overly fixed ordering of activation) of the nodes involved in the erroneous version of "deleterious" that was more similar to the familiar word? (Incidentally, I just caught myself on a typo: "similiar!")

-1 This theory is not considered accurate by itself any longer.

Granted the theory has evolved over the past 30 years, but it is my impression that the field still fundamentally supports a spreading activation architecture in production. What modifications would you make?

No this is not dyslexia and depending on the frequency it can be normal or abnormal. Its called aphasia and in adults it may be triggered by many different things. The primary explanation for chronic Aphasia is brain damage as per Neurolinguistics. However your limited example of aphasia was more likely caused by anxiety, lack of sleep, low blood pressure, hypoglycemia or any of the myriads of things which cause cognitive process anomalies.
Bellow is Figure 54-3 from Disorders of Languages: The Aphasia which represents the process of language formation. It is my contention that in addition to permanent brain lesions temporary disruptions of pathways caused by abnormal states of neurochemicals, nutrients and electrical signals trigger symptoms which can only be quantified as aphasia or aphasia like as well. Evidence based medicine reflects this by listing aphasia as some of the symptoms for hypoglycemia especially in diabetes, sleep deprivation, anxiety, low blood pressure. Of course I must mention Alogia in schizo typical patients showing the long and brief psychotic episodes cause temporary aphasia as well.

Aphasia sounds like a good explanation for extreme cases, but the question seems to be focussing on normal adults confusing syllables, particularly for two less common words. Even if fatigue, etc increases the prevalence, what are your thoughts on why particular pairs of words are confused by normal adults more often than other pairs of words?

@JeromyAnglim similar misconnections in the brain which may be due to psychology or physiology. People who have certain word confusions reinforced will repeat those behaviors. The overall structure of Wernicke Broca lend itself to similar failures. Much in the same way some microprocessors from different manufactures but of the same code processing class make similar mistakes under stress.


text:
What is the psychology of notification colour?
After reading the question What is the impact of showing the amount of unattended notifications to the user, it occurred to me that many notifications (certainly not all) are red, two examples being inbox messages here (SE) and any notification on Facebook.  Whereas, some notifications on StackExchange are in light blue (eg for badges and edits).  Green is often associated with check-mark notifications (such as on my AVG virus scan and as the accepted answer here).
(Anecdotal side note: I sometimes get the feeling "oh what have I done this time" when the red notification shows here and a "oh goody!" when the blue shows up).
There are many examples of different colours being used for different types of notifications.  What is the psychological basis of these notification colours?

It is all about attention and reaction time: Information are coded in visual, aural and tactile channel. Here you have primer of visual coding. Visual coding could be signs or text.
You have shorter time of reaction to primary colors (red yellow blue) and there is some kind of international standard which determine meaning of colors ( red-stop, green - walk... etc...) That is the reason why red.
I recomend you that you read some text in visual sensory perception, measuring time reaction, and some book of ergonomics psychology.
EDIT: Literature:
http://hfs.sagepub.com/content/17/6/542.short
http://www.who.int/fctc/guidelines/ArtElevenWogalterNine.pdf
EDIT2: Here are lot about reaction time:
http://biae.clemson.edu/bpc/bp/lab/110/reaction.htm

Thank you for this, do you have references to add to this answer?  Also, green is a primary colour for emitted light (yellow is a primary for pigments).

i could make some search when i come home. this information i recalled from lectures in ergonomics. thank you for info about cones.

Any links would be most appreciated - particularly about your first paragraph and reaction times, these intrigue me greatly.

I'm must say I'm a bit surprised by this question. To me it seems common knowledge that (a) red is the most alarm color (see traffic signs, traffic lights, brake lights on cars) and (b) while red is not an exact complement of blue it is the one color on the other side of the color circle that has the most attention value (see a). Blue is for non-urgent notifications, red is urgent. Why is it urgent on FB? Because FB is all about being excited to get many friend requests and stuff, while SE is relaxed and rational (so no need to scream "Notification!" with a red color).

@ICanFeelIt thank you for those references, exactly what I was after.

@what thank you, but I was after references to the psychology behind this (which I have received), not 'it is common knowledge that..'.  In some cultures red is considered as 'alarm' etc.

http://meta.cogsci.stackexchange.com/questions/706/how-to-deal-with-questions-that-have-a-perfect-answer-on-wikipedia


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Pathological distress caused by being discouraged to say "thanks" on online communities
The Stack Exchange network users are not encouraged to leave comments expressing thanks.

Please do not add a comment on your question or on an answer to say "Thank you". Comments are meant for requesting clarification, leaving constructive criticism, or adding relevant but minor additional information – not for socializing. If you want to say "thank you," vote on or accept that person's answer, or simply pay it forward by providing a great answer to someone else's question.

Given some people are taught from a preschool age to express thanks and this practice is reinforced throughout a lifetime. So coming to an online community can be difficult for some people not to express thanks.
What is happening psychologically when an individual has immense discomfort (to a point of preferring the discomfort of not complying with the wishes of an online community), that is almost compulsive in having to continue with an instilled social habit, such as expressing thanks.
Nb To me, it could be related to cognitive-dissonance, but this doesn't seem to be the correct term.

@ladislas you are most very welcome, please feel free to ask any questions, even if it is for your own curiosity (aka personal needs) you can ask in the guise of a generalised question.. there are people who do that here :)

DISCLAIMER: I do not have any official education in cognitive sciences.
Maybe problem is not in saying "thank you", for me upvoting is very close to saying thank you.
I think it is rather obvious what are benefits from discouraging "thank you", it would be hard to find real content in "thanks forest".
Perhaps people wish that receiver knows who said thank you
I Joe want Marc to know that 'I, Joe' am thankful.

Lol a thanks forest, you made me smile, I really like the logic of your answer. It a whole different take on the question.. +1 (so you know ;) haha But there is still this issue of obligation, as I have now to give you feedback and thanks, which surpasses the vote, I want YOU to know I the OP am grateful. I don't have this with other people's post (sounds like other people's children.. good title for a movie) cheers and thanks, em thank you, em ty , em tyvm :P

Well, you actually changed my mind a bit, your first comment made me feel really good and happy, much more than ordinary upvote :)  However, if it was "thanks" oneliner, effect would probably be much much weaker.

4 the comment was genuine minus the thanks joke, but what happens when a person posts a poor answer, and I am still compelled to thank them for their effort  ps I'm not referring to me personally saying ty.. But it's getting confusing how to word it


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When a person starts to scratch, why does this often start others to scratch?
Often, when a person starts scratching and complains of being itchy, whether they suggest there might be a bug biting them (for example fleas, head lice, mites) another person with them will start to feel itchy, just at the thought of it. The cause may not always be an insect.
This seems to occur with sources of itching that cannot be seem, (for example with mosquitos that produce large bites and can usually be seen flying around, people may not tich unless being bitten. In fact they sometime joke how they are usually the ones being bitten and aren't now and the like), but this could be a false assumption on my part.
Why is it that people can feel itchy when another person feels itchy and starts scratching and complaining?
What happens within the brain, what changes occur neurochemically and along which neural networks and regions?
Is this influenced by how visible the cause of the itch and the resulting marks left by this (example bites)?
Is there theory about the evolutionary purpose of this, perhaps it is a survival mechanism to help prevent infestation?
Answers can address only one of these aspects being asked, as it encompasses many fields.

So not unlike the contagiousness of yawning whether or not that is actually so. But regardless I don't think that scratching is as contagious even if it might not be.

@DanD. I'm not sure, but would like to know. and why?? for both

There are two functions that I'm aware of that are involved, though there of course may be more I'm simply unaware of.
The first is so-called mirror neurons. Cognitively, neurologically, and evolutionary, we generally assume that the brain tends to be very efficient to be able to get its immense job done in so little space, so quickly, with so little 'power' (food). One result of this pressure is re-use, so that the same parts of the brain that are used in active experience of something are also used for recalling, thinking about, and indeed perceiving others experience similar things (thus the mirror neurons). To see someone else itch compels us to think about itching, and to recall/think about/understand itching is to activate the same parts of the brain that register the concept of itching in ourselves.
This then neatly leads into (and overlaps) with another set of effects: conscious awareness and selective attending. The nature of our conscious awareness is that it is limited - we can't consciously attend to everything at once. And thus we have perceptual and cognitive filters (and we have lots of theories over time that have developed this context - I think the "leaky filter" hybrid model being the most recent, but I can't recall the name of the researcher(s) who came up with it).
This set of functions give us the cocktail party effect and the invisible gorilla experiments, change blindness, and so many fun others. It also effects how we respond to "how happy are you" questions; another fun experiment was that finding a nickle on a copying machine before you get asked about your happiness and satisfaction in life causes one to respond more positively to even general questions.
But I digress...
In contagious yawning - and in itching! - the act of perceiving someone itching can direct our attention to personal comfort and any potential itchiness. For instance, if you are fully dressed right now (including socks): you know that 'seam' at the end of the sock down by your toes? Does that always go above your toes on the top of your foot, or does it sometimes kind of work it's way down so it's at the bend of your toes underneath your foot?
Well, I have gone all morning without thinking about it, but now I realize my sock is a little twisted, I think the heel of the sock has slid a bit off-center, and the top of my boot is rather tight while the lower part of the laces could be tighter. Also, my ankle kind of itches a little.
The fact of modern life is, quite frankly, there is always something that could use a good scratching! Like my back right now...answering this question is making me wish for a scratching post. Multiple layers of clothes of varying fibers, little skin folds, body hair, all those tiny little follicles and pores mean there's bound to be at least one little pimple somewhere, and even if you are very flexible there's always places that aren't terribly easy to reach...
So perhaps a better question is "why aren't we itchy all the time?!" Thankfully, most of us have filters that consider many of these sensations relatively unimportant, so they don't get passed over into something that captures our conscious awareness. Also, we are busy: there's lots to think about in the world, so we tend to only think about it when we are given a cue like trying on clothing, or looking at an irritated/injured piece of skin...or seeing someone else itching.
Given these are cognitive processes, we can also view what happens when they go wrong, as manifested in symptoms and disorders such as intrusive thoughts, "sensitive skin" or tactile sensitivity (especially common in the autism spectrum), etc.
TLDR;
First we perceive, then we imagine, then we experience - empathy! Sad songs can make us sad, in part because they remind us of the sadness that is an unavoidable part of life, and also in part because to think about sadness we can't help but feel at least a little sad; the only reason we aren't sad all the time is because there are happy things to think about, too.
Itching is like an elephant - try not to think about it. Oops, too late!


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What are the possible causes of pettiness?
There is a question about pettiness Is it possible to quantify 'pettiness' in a personality?
Which gives a good example of how some people can focus on seemingly unimportant issues, when there are more obvious issues that would seem to warrant attention.
What would cause a person to focus, even fixate on small, petty things; for example:

a co-worker's tardiness, when the employer's company is facing a takeover and jobs may be lost.
the makeup one of the school Mum's was wearing, when there's been a robbery at the school

I am wondering what the possible causes of pettiness may be?

I might think that the reasons to behave in some way or other lies on every person individually; although we have similar basis. E.g. for the first example, the situation of the company could be an enhancing factor for this psychological bias, because we are programmed to be competitive against our own species members (Because of natural selection), and a worker might think (consciously or not), that his chances to keep the job are better if he is better than others, which may lead to devalue other people or overrate himself at work. Sorry for my English, have a nice day.

When jobs may be lost, is focus on tardiness a petty argument?

There is something called the "bike-shed effect" (law of triviality) which argues it is normal "... that members of an organization give disproportionate weight to trivial issues."

There can always be many variables for what causes human behavior, within this answer I will focus on three more obvious or, perhap, likely causes for pettiness within individuals.
This could be one of a variety of causes stemming from the following:

Schadenfreude
Obsessive Compulsive Disorder (or related disorders)
Disorders on the Autistic spectrum

Schadenfreude:
In the majority of situations this would be the most likely cause of such pettiness, as it is applicable to a more mainstream type of behavior. The chance to show up a deficit or shortcoming in another, motivated by jealousy of, or a feeling of unease stemming from threat  by, that person..

We are primed for pettiness, programmed to notice seemingly inconsequential gradations, but for good reason: Being chronically dissatisfied is an effective stimulus to best your more complacent peers. (1)

This could well be the result of schadenfreude (translated to harm-joy), which refers to the pleasure people gain from the misfortunes of someone they perceive to be a high achiever or be envious of. This is based on envy derived from poor self esteem and/or lack of validation of that person's self esteem and a reaction to a perceived threat, from a fellow high-achiever.
The greater the  focus on seemingly petty things, the greater the individual's  psychic conflict or neediness and by this I refer to, the need for validation of self-worth and reaffirming their rank as a human being within a given community.  For such anxiety to cloud judgement to give a, seemingly, inconsequential issue, precedence over what seem to be more important issues. For this individual the need to validate themselves as a person is greater than national, global or even cosmic issues for which this individual has no control over, and which may have no immediate effect on that person's life.

The present research shows that people with low self-esteem experience more schadenfreude toward the misfortune of a high- achiever than those with high self-esteem and that this relationship is mediated by the self-threat evoked by the high-achiever. Moreover, the indirect relationship between self-esteem and schadenfreude is contingent on an opportunity of self-affirmation. When no self-affirmation opportunity is available, low-self-esteem participants experience a stronger self-threat when confronted with a high-achiever, and this self-threat increases their schadenfreude. (2)

Obsessive Compulsive Disorder (OCD)

Although OCD is usually referring to the compulsive ritualised activities of an individual, as a result of an underlying obsession. If an observer with OCD, witness what may be regarded to most people as petty, but the observed behavior happens to cross into the area of obsession for that person, it could well be that person's attempt to alleviate their own anxiety that is triggered by the perceived aberrant behavior. An example being, observing someone leave the toilet cubicle and restroom without washing their hands.

Obsessive-Compulsive Disorder, or OCD, is an anxiety disorder and is characterized by recurrent, unwanted thoughts (obsessions) and/or repetitive behaviors (compulsions). Repetitive behaviors such as hand-washing, counting or cleaning are often performed with the hope of preventing obsessive thoughts or making them go away. Performing these so-called "rituals," however, provides only temporary relief, and not performing them markedly increases anxiety

Disorders on the Autistic spectrum

People with disorders that lie on the autistic spectrum, can frequently have preoccupation or obsession with details, that may seem inconsequential to others, or even petty. As with OCD, this perceived pettiness could be an attempt to alleviate the individual's anxiety and to assist in making sense of the world, as this type of individual is frequently inflexible and views the world through a set of structured ideas, that do not easily facilitate or blend with the fluid nature of life and human behavior.

“Obsessions”, “circumscribed interests”, “special interests”, “routines”, “rituals” ,
  “preoccupations” are some of the terms used when describing the behaviour of young
  children with autism. These behaviours belong to one of the three core areas of
  impairment in children with autism. (4)

References:

Why You Think You'll Never Stack Up by Carlin Flora, Psychology Today (1)
Self-Esteem, Self-Affirmation, and Schadenfreude
Wilco W. van Dijk, Guido M. van Koningsbruggen, Jaap W. Ouwerkerk and Yoka M. Wesseling DOI:  10.1037/a0026331 PDF (2)
Obsessive-Compulsive Disorder (OCD)
Brain and Behavior Research Foundation
Restricted, repetitive and stereotyped patterns of behaviour, interest and activities
Dr Avril V Brereton, Monash University  PDF (4)

Schadenfreude is an interesting argument

Another general possibility is a personality geared towards perfectionism, which is one of the components of Conscientiousness, one of the Big Five personality traits. Individuals who strive for perfect solutions may focus on trivial components.

https://en.wikipedia.org/wiki/Conscientiousness

A similar issue is described as maximizing vs. satisficing: does one take a "good enough" answer, or obsess about diminishing returns? This link explains the concept in psychology.

https://www.psychologytoday.com/gb/blog/science-choice/201506/satisficing-vs-maximizing

Narcissism may be petty by definition. For example, materialism plays to the desire of admiration in Narcissistic Personality Disorder. More generally, I'd associate it with a certain kind of maturity deficit. Such are common in Cluster B personality disorders and not just Narcissistic Personality Disorder:Notes on Narcissistic Personality Disorder. So, Envy would be one component. Failure to tolerate any criticism. Rash responses, temper tantrums. Keeping up with the Jonses'.
From this I'd expect pettiness to correspond with relatively low Openness to experience, low Agreeableness, High Neuroticism. Most petty people I've known aren't especially Extroverted. Conscientiousness overlaps in Narcissism in odd ways.
Low Openness, and High Neuroticism tends to correspond with Low Fluid Intelligence.
So I'm not sure if pettiness itself can be measured directly, but I think measures of the Big 5 Personality Traits and Fluid Intelligence can be used to indicate this quality.
Some Notes on Meanness in Narcissism from Psychology Today

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