Be Careful When Assuming the Obvious: Commentary on "The placement of   the head that minimizes online memory: a complex systems approach"
  Ferrer-i-Cancho (2015) presents a mathematical model of both the synchronic and diachronic nature of word order based on the assumption that memory costs are a never decreasing function of distance and a few very general linguistic assumptions. However, even these minimal and seemingly obvious assumptions are not as safe as they appear in light of recent typological and psycholinguistic evidence. The interaction of word order and memory has further depths to be explored. 
Phillip M. Alday
cs.CL