title: Are perceptuo-motor decisions really more optimal than cognitive decisions?
abstract: Human high-level cognitive decisions appear sub-optimal (Kahneman, Slovic, & Tversky, 1982; Kahneman & Tversky, 1979). Paradoxically, perceptuo-motor decisions appear optimal, or nearly optimal (Trommershäuser, Maloney, & Landy, 2008). Here, we highlight limitations to the comparison of performance between and within domains. These limitations are illustrated by means of two perceptuo-motor decision-making experiments. The results indicate that participants did not optimize fundamental performance-related factors (precision and time usage), even though standard analyses may have classed participants as 'optimal'. Moreover, simulations and comparisons across our studies demonstrate that optimality depends on task difficulty. Thus, it seems that a standard model of perceptuo-motor decision-making fails to provide an absolute standard of performance. Importantly, this appears to be a limitation of optimal models of human behaviour in general. This, in conjunction with non-trivial evaluative- and methodological differences, suggests that verdicts favouring perceptuo-motor, or perceptual, systems over higher-level cognitive systems in terms of level of performance are premature.
authors.affiliation: School of Psychology, Cardiff University, United Kingdom; School of Experimental Psychology, University of Bristol, United Kingdom. Electronic address: a.jarvstad@bristol.ac.uk.
authors.forename: Andreas
authors.initials: A
authors.lastname: Jarvstad
authors.affiliation: School of Psychology, Cardiff University, United Kingdom; Department of Psychological Sciences, Birkbeck, University of London, United Kingdom.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Hahn
authors.affiliation: School of Psychological Sciences, The University of Manchester, United Kingdom.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Warren
authors.affiliation: School of Psychology, Cardiff University, United Kingdom.
authors.forename: Simon K
authors.initials: SK
authors.lastname: Rushton
mesh_terms: D000328:Adult; D003071:Cognition / Q000502:physiology*; D003657:Decision Making / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009068:Movement; D010465:Perception / Q000502:physiology*; D010775:Photic Stimulation; D011597:Psychomotor Performance; D011930:Reaction Time / Q000502:physiology
keywords: Decision-making; Motor planning; Optimality; Perceptuo-motor