Non-classicality in mental states : an experimental study with ambiguous   audio (music) stimuli
  This paper attempts to address the question that whether the present physical or mathematical theories are sufficient to understand the complexities of human brain when it interacts with the external environment in the form of an auditory stimulus.There have been efforts reporting that the introduction of ambiguity in visual stimuli causes effects which can't be explained classically.In this paper,it is investigated whether ambiguity in auditory stimuli can introduce any non-classical effects in human brain.Simple experiments were performed on normal subjects where they listened to an ambiguous auditory signal and responded to a question with 'yes' or 'no'.The outcome of the test showed that the classical formula of total probability does not hold true in this case.Results were interesting and indicate that there is a definite non-classicality in mental states in perception of ambiguous audio stimuli. 
Souparno Roy, Ranjan Sengupta, Tarit Guhathakurata, Dipak Ghosh
q-bio.NC math.PR quant-ph