Beyond Nature Versus Nurture: the Emergence of Emotion

Abstract

Affective science is stuck in a version of the nature-versus-nurture debate, with theorists arguing whether emotions are evolved adaptations or psychological constructions. We do not see these as mutually exclusive options. Many adaptive behaviors that humans have evolved to be good at, such as walking, emerge during development - not according to a genetically dictated program, but through interactions between the affordances of the body, brain, and environment. We suggest emotions are the same. As developing humans acquire increasingly complex goals and learn optimal strategies for pursuing those goals, they are inevitably pulled to particular brain-body-behavior states that maximize outcomes and self-reinforce via positive feedback loops. We call these recurring, self-organized states emotions. Emotions display many of the hallmark features of self-organized attractor states, such as hysteresis (prior events influence the current state), degeneracy (many configurations of the underlying variables can produce the same global state), and stability. Because most bodily, neural, and environmental affordances are shared by all humans - we all have cardiovascular systems, cerebral cortices, and caregivers who raised us - similar emotion states emerge in all of us. This perspective helps reconcile ideas that, at first glance, seem contradictory, such as emotion universality and neural degeneracy.

Keywords: Complex systems; Dynamical systems; Emergence; Evolution; Fear; Theory of emotion.

Fig. 1

At any moment, a person has goal(s) and is in a particular brain-body state. Here, we visualize this as a 2-dimensional space (x–y plane), but of course, it is a very high-dimensional space with all dimensions of neural activity, physiological activity, behavior, and cognition. The z dimension represents the stability or attractive force of all possible locations in this high-dimensional space. Some locations – attractor basins, in blue – become more attractive and stable through development and reinforcement. If a person is in a nearby, but less stable state, they will be pulled toward these more attractive states like a ball rolling downhill. We call these emotion states discrete because the phase transitions between them are nonlinear (rather than gradual and linear; Korolkova, 2018)