Oct 2020

How we evaluate and overrule our perceptual decisions

Speaker: William Turner

26th November 2020


To navigate the world safely, it is critical that we are able to rapidly evaluate and change our mind about our perceptual decisions. For example, imagine being unable to overrule a decision to cross the street when you realise a speeding car is approaching. In situations such as this, even small delays in the time it takes for you to change your mind can have serious consequences. In this talk, PhD Student, William Turner, presents findings from three studies which examined the cognitive processes underlying changes of mind (Studies 1-2) and retrospective evaluations of decision confidence (Study 3). Study 1 found that the likelihood and speed of decision reversals depends on both relative and absolute sources of sensory information, while Study 2 found that even the very earliest sensory information one receives influences later change-of-mind decisions. These results challenge existing computational models of the processes underlying changes of mind. Will presents new variants of these models which better account for these findings, and outline ways in which their assumptions can be tested further. Finally, Study 3 shows that information which is seemingly extraneous to a perceptual decision—specifically the amount of effort invested into reporting a decision outcome—nevertheless influences retrospective judgements of decision confidence. This suggests that humans are sensitive to a ‘motoric sunk cost effect’ whereby forgone physical effort expenditure can inflate decision confidence.

Speaker Bio

William Turner is a PhD candidate in the Melbourne School of Psychological Sciences. He is interested in the cognitive and neural processes underlying perceptual decisions and decision reversals.

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