title: Speeded saccadic and manual visuo-motor decisions: Distinct processes but same principles.
abstract: Action decisions are considered an emergent property of competitive response activations. As such, decision mechanisms are embedded in, and therefore may differ between, different response modalities. Despite this, the saccadic eye movement system is often promoted as a model for all decisions, especially in the fields of electrophysiology and modelling. Other research traditions predominantly use manual button presses, which have different response distribution profiles and are initiated by different brain areas. Here we tested whether core concepts of action selection models (decision and non-decision times, integration of automatic and selective inputs to threshold, interference across response options, noise, etc.) generalise from saccadic to manual domains. Using two diagnostic phenomena, the remote distractor effect (RDE) and 'saccadic inhibition', we find that manual responses are also sensitive to the interference of visual distractors but to a lesser extent than saccades and during a shorter time window. A biologically-inspired model (DINASAUR, based on non-linear input dynamics) can account for both saccadic and manual response distributions and accuracy by simply adjusting the balance and relative timings of transient and sustained inputs, and increasing the mean and variance of non-decisional delays for manual responses. This is consistent with known neurophysiological and anatomical differences between saccadic and manual networks. Thus core decision principles appear to generalise across effectors, consistent with previous work, but we also conclude that key quantitative differences underlie apparent qualitative differences in the literature, such as effects being robustly reported in one modality and unreliable in another.
authors.affiliation: CUBRIC - School of Psychology, Cardiff University, Cardiff CF10 3AT, Wales, United Kingdom; INSERM, U1028, CNRS, UMR5292, Lyon Neuroscience Research Center, Brain Dynamics and Cognition Team, Lyon F-69000, France. Electronic address: BompasAE@Cardiff.ac.uk.
authors.forename: Aline
authors.initials: A
authors.lastname: Bompas
authors.affiliation: CUBRIC - School of Psychology, Cardiff University, Cardiff CF10 3AT, Wales, United Kingdom.
authors.forename: Craig
authors.initials: C
authors.lastname: Hedge
authors.affiliation: CUBRIC - School of Psychology, Cardiff University, Cardiff CF10 3AT, Wales, United Kingdom.
authors.forename: Petroc
authors.initials: P
authors.lastname: Sumner
mesh_terms: D003657:Decision Making / Q000502:physiology*; D006801:Humans; D008959:Models, Neurological; D008960:Models, Psychological; D016571:Neural Networks, Computer; D011597:Psychomotor Performance; D011930:Reaction Time; D012438:Saccades
keywords: Action selection; Competition; Modelling; Reaction time; Response modalities