Sam Clarke (University of Pennsylvania): ‘Number adaptation: a critical look’

Abstract: A received view in psychology and neuroscience is that humans visually adapt to the number of items in a seen collection. This conclusion is motivated by more than 30 published studies, is supported by phenomenologically compelling illustrations, and is often used to motivate weighty philosophical claims about the contents of experience and the function of perception.  

If you had asked me only very recently, I would have told you that the existence of number adaptation was decisively established many times over. However, this talk takes a sceptical look at the phenomenon. After noting several results which sit awkwardly with the existence of genuine number adaptation, I offer an independently motivated alternative explanation for reported cases of number adaptation: on this view, humans adapt to perceived items, but not their numerical quantity. I then describe a series of experimental studies (run in collaboration with Sami Yousif and Elizabeth Brannon) that bear out the predictions of this novel alternative and raise further problems for the existence of genuine number adaptation.

Sam Clarke is a MindCORE Research Fellow at the University of Pennsylvania, splitting his time between philosophy, psychology and linguistics, and in July (2023) he will be starting as an assistant professor of philosophy at the University of Southern California. At the moment, most of Sam’s research is focussed on trying to understand bits of the non-linguistic mind – i.e., psychological capacities that emerge independently of natural language, and psychological processes that do not depend on linguistically structured representations.