The role of hedonics in the Human Affectome

Abstract

Experiencing pleasure and displeasure is a fundamental part of life. Hedonics guide behavior, affect decision-making, induce learning, and much more. As the positive and negative valence of feelings, hedonics are core processes that accompany emotion, motivation, and bodily states. Here, the affective neuroscience of pleasure and displeasure that has largely focused on the investigation of reward and pain processing, is reviewed. We describe the neurobiological systems of hedonics and factors that modulate hedonic experiences (e.g., cognition, learning, sensory input). Further, we review maladaptive and adaptive pleasure and displeasure functions in mental disorders and well-being, as well as the experience of aesthetics. As a centerpiece of the Human Affectome Project, language used to express pleasure and displeasure was also analyzed, and showed that most of these analyzed words overlap with expressions of emotions, actions, and bodily states. Our review shows that hedonics are typically investigated as processes that accompany other functions, but the mechanisms of hedonics (as core processes) have not been fully elucidated.

Keywords: Displeasure; Nucleus accumbens; Orbitofrontal cortex; Pain; Pleasure; Reward; Valence; Ventromedial prefrontal cortex.

Fig. 1.

Organizational structure of the hedonics-related feeling words. The illustration shows that hedonic value is an integral part of most of the categories of feelings that have been investigated in the Human Affectome Project. Categories that were missing from or were additionally found in the analysis of the hedonic terms are displayed in grey. For example, fun has been identified as a potential additional category. Further, hedonic value and motivation (which did not emerge in the word list) seem to be closely connected, in the sense that, based on, for example, needs, preferences, and desires, positive hedonic value can induce approach and negative hedonic value can induce avoidance/escape behavior thus motivating an organism. However, anger, which did not emerge in the hedonics-related word list, holds an exceptional position, as it refers to a negative affective state leading to approach behavior (cf. Section 3).