Aiming for the stomach and hitting the heart: dissociable triggers and sources for disgust reactions.

Disgust reactions can be elicited using stimuli that engender orogastric rejection (e.g., pus and vomit; core disgust stimuli) but also using images of bloody injuries or medical procedures (e.g., surgeries; blood [body] boundary violation [B-BV] disgust stimuli). These two types of disgust reaction are presumed to be connected by a common evolutionary function of avoiding either food- or blood-borne contaminants. However, reactions to bloody injuries are typically conflated with reactions to the potential pain being experienced by the victim. This may explain why the two forms of "disgust", although similarly communicated (through self-report and facial expressions), evince different patterns of physiological reactivity. Therefore, we tested whether the communicative similarities and physiological dissimilarities would hold when markers of potential contamination in the latter category are removed, leaving only painful injuries that lack blood or explicit body-envelope violations. Participants viewed films that depicted imagery associated with (a) core disgust, (b) painful injuries, or (c) neutral scenes while we measured facial, cardiovascular, and gastric reactivity. Whereas communicative measures (self-report and facial muscles) suggested that participants experienced increased disgust for core disgust and painful injuries, peripheral physiology dissociated the two: core disgust decreased normal gastric activity and painful-injury disgust decelerated heart rate and increased heart rate variability. These findings suggest that expressions of disgust toward bodily injuries may reflect a fundamentally different affective response than those evoked by core disgust and that this (cardiovascularly mediated) response may in fact be more closely tied to pain perceptions (or empathy) rather than contaminant-laden stimuli

Habits without values

Habits form a crucial component of behavior. In recent years, key computational models have conceptualized habits as arising from model-free reinforcement learning (RL) mechanisms, which typically select between available actions based on the future value expected to result from each. Traditionally, however, habits have been understood as behaviors that can be triggered directly by a stimulus, without requiring the animal to evaluate expected outcomes. Here, we develop a computational model instantiating this traditional view, in which habits develop through the direct strengthening of recently taken actions rather than through the encoding of outcomes. We demonstrate that this model accounts for key behavioral manifestations of habits, including insensitivity to outcome devaluation and contingency degradation, as well as the effects of reinforcement schedule on the rate of habit formation. The model also explains the prevalent observation of perseveration in repeated-choice tasks as an additional behavioral manifestation of the habit system. We suggest that mapping habitual behaviors onto value-free mechanisms provides a parsimonious account of existing behavioral and neural data. This mapping may provide a new foundation for building robust and comprehensive models of the interaction of habits with other, more goal-directed types of behaviors and help to better guide research into the neural mechanisms underlying control of instrumental behavior more generally

Motivation and cognitive control in depression

Depression is linked to deficits in cognitive control and a host of other cognitive impairments arise as a consequence of these deficits. Despite of their important role in depression, there are no mechanistic models of cognitive control deficits in depression. In this paper we propose how these deficits can emerge from the interaction between motivational and cognitive processes. We review depression-related impairments in key components of motivation along with new cognitive neuroscience models that focus on the role of motivation in the decision-making about cognitive control allocation. Based on this review we propose a unifying framework which connects motivational and cognitive control deficits in depression. This framework is rooted in computational models of cognitive control and offers a mechanistic understanding of cognitive control deficits in depression

Self-Control in Cyberspace: Applying Dual Systems Theory to a Review of Digital Self-Control Tools

Many people struggle to control their use of digital devices. However, our understanding of the design mechanisms that support user self-control remains limited. In this paper, we make two contributions to HCI research in this space: first, we analyse 367 apps and browser extensions from the Google Play, Chrome Web, and Apple App stores to identify common core design features and intervention strategies afforded by current tools for digital self-control. Second, we adapt and apply an integrative dual systems model of self-regulation as a framework for organising and evaluating the design features found. Our analysis aims to help the design of better tools in two ways: (i) by identifying how, through a well-established model of self-regulation, current tools overlap and differ in how they support self-control; and (ii) by using the model to reveal underexplored cognitive mechanisms that could aid the design of new tools.Comment: 11.5 pages (excl. references), 6 figures, 1 tabl