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.
Beyond nature versus nurture: The emergence of emotionFor over 100 years psychologists have debated whether emotions are more like soldered circuits whose designs are encoded in our genes, or more like software programs written by context and experience-whether, in the language of bygone debates within biology, emotions reflect nature or nurture. Most attempts to reconcile the two perspectives involve a compromise in which nurture modifies the innate emotion programs given to humans by nature (i.e., by our genes; Mesquita & Walker, 2003;Matsumoto & Hwang, 2012;Levenson et al., 2007;Oatley, Keltner, & Jenkins, 2006). But this compromise still implies that we can meaningfully differentiate what humans are "born with" from what happens to their bodies as they interact with their environment, and indeed that doing so is of vital scientific importance.Contemporary evolutionary biology has largely moved on from the nature-nurture debate, as accumulating theory and evidence complicates the boundary between phylogeny and ontogeny (Hochman, 2013). We see the future of affective science as one that has caught up to modern biology by no longer considering evolution and development, or, as some would have it, adaptive specificity and mechanistic degeneracy (Edelman and Gally, 2001), as competing explanations (Bergman & Beehner, 2022). From here, we propose that at the level of goaldirected behavior, emotions are relatively universal, discrete, and adaptive-one might say evolved-but also necessarily constructed through the body's interaction with the environment.Adaptive traits primarily manifest as the organism interacts with, and develops wit...