Jason A. Clark: University of Osnabrueck Institute for Cognitive Science

Within emotion theory, it is common for theorists to order emotions along phylogenetic and developmental scales. ‘Basic emotions’ (such as fear and joy) are seen as having a longer evolutionary history that we share with other animals, and as emerging earlier in development. Higher-cognitive emotions (such as shame and pride) are often seen as arising de novo in the human line, and late in development, and both their evolution and development are seen as arising from uniquely human higher-cognitive capacities.
However, an increasing number of emotion theorists are converging on the idea that higher-cognitive emotions in humans are homologous to simpler forms of these emotions in nonhuman animals, and branch off from developmentally earlier and simpler precursors. One problem faced by such theories is the fact that the more basic forms of emotions appear to persist as such, despite the emergence of higher-cognitive forms. This is inconsistent with the standard view of homology according to which ancestral traits are transformed into derived traits in a continuous series in which the original form of the trait is lost or modified.
One solution to this problem which reconciles evolutionary and developmental transformations with the persistence of the original forms is to construe these homologies as serial homologies. In serial homology a trait is duplicated, and while the original trait usually remains in place and functions as before, the duplicate trait is allowed to vary independently in response to potentially distinct evolutionary pressures. According to this model, ancestral ‘basic’ forms of emotions (or some of their components) are duplicated. The basic forms of these emotions are retained, while the duplicates are allowed to vary within uniquely human evolutionary, cultural and cognitive contexts. This thesis is illustrated using a variety of emotions, including shame, pride, disgust, and laughter. Finally, while serial homologies are often invoked to explain behaviors, they are not typically applied directly to psychological capacities. I consider some of the general issues involved in such applications, including some potential brain mechanisms that might underlie them.