On the challenges and mechanisms of embodied decisions

Abstract

Neurophysiological studies of decision-making have focused primarily on elucidating the mechanisms of classic economic decisions, for which the relevant variables are the values of expected outcomes and action is simply the means of reporting the selected choice. By contrast, here we focus on the particular challenges of embodied decision-making faced by animals interacting with their environment in real time. In such scenarios, the choices themselves as well as their relative costs and benefits are defined by the momentary geometry of the immediate environment and change continuously during ongoing activity. To deal with the demands of embodied activity, animals require an architecture in which the sensorimotor specification of potential actions, their valuation, selection and even execution can all take place in parallel. Here, we review behavioural and neurophysiological data supporting a proposed brain architecture for dealing with such scenarios, which we argue set the evolutionary foundation for the organization of the mammalian brain.

Model-Based Approaches to Active Perception and Control

“…It is also worth noting that the importance of action for cognition is exemplified in many more domains than discussed in this paper. For example, there are important demonstrations that action dynamics are required to stabilize perceptual learning [148] and sequence learning [149] and that action should be considered as part and parcel of decision processes-for example, decision-makers consider both rewards and action costs jointly, and action dynamics feed back on decisions [45,50], and one can offload decisions to one's own behaviour [83,150]. All of these examples, and other, suggest that action is part of cognitive processing and not just a consequence of it [53].…”

“…This "control view" of brain and cognition has its historical roots in cybernetics [47][48][49], which emphasized the importance of studying control dynamics and feedback mechanisms in living organisms. It takes seriously the evolutionary arguments that our cognitive abilities were originally developed to make rapid, adaptive choices in situated contexts as part of our interaction with objects and other animals, not to solve lab tasks [50][51][52]; and even the most sophisticated (higher) cognitive abilities may be better seen as elaborations of the basic cognitive architecture of our early evolutionary ancestors. Therefore, this view immediately prompts a pragmatic (or action-centred) perspective on brain and cognition [15,53], which shifts the focus of investigation from "what happens in the brain in between the reception of a stimulus and the computation of a response?"…”

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

“…Such motor encoding of competing action goals could facilitate the incorporation of movement-related costs and constraints into decisions related to action selection and may enable more rapid responding once the target is selected (Christopoulos et al 2015;Cisek 2006;Cisek and Pastor-Bernier 2014;Cos et al 2011Cos et al , 2012Cos et al , 2014. In contrast to experiments described above, in the real world, due to continuous shifts of overt or covert attention, potential action goals often arise sequentially over time with uncertainty about the number of options that will become available before we need to act.…”

Moving forward in perceptual decision making

“…However, there is also evidence to support the view that different processes of perceptual decision making might happen in parallel (2,11). According to this view, the brain is processing sensory information to specify, in parallel, several potential actions that are currently available, and actions can, in turn, feed back into the perceptual decision-making process (11,12). In light of these considerations, the findings reported in the study by Rahnev et al (1) may not provide unequivocal evidence for a hierarchical or serial organization of the processes underlying perceptual decision making.…”

“…It is intuitive to assume that stimulus selection occurs prior to a perceptual decision and a subsequent confidence judgment that eventually leads to an action. However, there is also evidence to support the view that different processes of perceptual decision making might happen in parallel (2,11). According to this view, the brain is processing sensory information to specify, in parallel, several potential actions that are currently available, and actions can, in turn, feed back into the perceptual decision-making process (11,12).…”