The snooze of lose: Rapid reaching reveals that losses are processed more slowly than gains.

Abstract

Decision making revolves around weighing potential gains and losses. Research in economic decision making has emphasized that humans exercise disproportionate caution when making explicit choices involving loss. By comparison, research in perceptual decision making has revealed a processing advantage for targets associated with potential gain, though the effects of loss have been explored less systematically. Here, we use a rapid reaching task to measure the relative sensitivity (Experiment 1) and the time course (Experiments 2 and 3) of rapid actions with regard to the reward valence and probability of targets. We show that targets linked to a high probability of gain influence actions about 100 ms earlier than targets associated with equivalent probability and value of loss. These findings are well accounted for by a model of stimulus response in which reward modulates the late, postpeak phase of the activity. We interpret our results within a neural framework of biased competition that is resolved in spatial maps of behavioral relevance. As implied by our model, all visual stimuli initially receive positive activation. Gain stimuli can build off of this initial activation when selected as a target, whereas loss stimuli have to overcome this initial activation in order to be avoided, accounting for the observed delay between valences. Our results bring clarity to the perceptual effects of losses versus gains and highlight the importance of considering the timeline of different biasing factors that influence decisions.

Luring the Motor System: Impact of Performance-Contingent Incentives on Pre-Movement Beta-Band Activity and Motor Performance

“…Electrophysiologically, this finds echo with results showing that lateral intraparietal neurons initiate their firing more quickly in response to rewarding versus non-rewarding stimuli (Peck et al, 2009). The present findings may thus provide neurophysiological grounds for the behavioral evidence that decision-making unfolds more quickly in contexts where the best option is a net gain compared with when it is loss avoidance (Chapman et al, 2015). Additionally, these results may help explain recent evidence for mixed representations in the literature, in that the observed temporal shift in encoding may have been obscured using less temporally-resolved techniques such as fMRI.…”

“…An interesting possibility is that expected value and motivational salience may be expressed at different moments during movement preparation. Support for this comes from behavioral work by Chapman et al (2015), who demonstrated that when forced to respond rapidly (reaction times Յ425 ms), action selection is quicker when the best possible outcome entails obtaining a reward compared with evading a punishment. Importantly, however, this reward-related processing advantage disappeared when response initiation was delayed by 500 ms, suggesting that when there are no net positive options, it takes extra time for the brain to implement rational behavior.…”

The sequential encoding of competing action goals involves dynamic restructuring of motor plans in working memory

“…Chapman et al (2010a, b); Gallivan and Chapman (2014)]. Whereas this finding is certainly novel in the context of previous work that has used (or relied on) spatial averaging behavior to reveal the parallel encoding of competing movements [and/or probe the effects of distractors on reaching; see Buc Calderon et al (2015); Chapman et al (2015); Gallivan et al (2011);Meegan and Tipper (1998); Stewart et al (2014); Tipper et al (1997Tipper et al ( , 2000], the absence of spatial averaging effects here is perhaps to be expected, given that movements were initiated only after the target was cued.…”

Models, movements, and minds: bridging the gap between decision making and action

“…Adapted from Ref. . (C) Response‐locked analysis of changes in primary motor cortex (M1) excitability to transcranial magnetic stimulation (TMS) pulses, measured via normalized motor evoked potentials (MEPs) toward chosen (red) versus unchosen (blue) options.…”

“…80,81 Under these conditions, participants initially execute an averaged movement between both options before ultimately selecting one. Furthermore, it has been shown that the probability, 81 number, 80,82,83 spatial arrangement, 80,84 luminance, 85 reward-association, 86,87 and symbolic representation 88 of targets all impact rapid reach trajectories.…”