Emotion Expressions: On Signals, Symbols, and Spandrels-A Response to Barrett (2011)

We appreciate Barrett's (2011, this issue) comments and her discussion of how our two-stage model is and is not consistent with Darwin's views on the evolution of emotion expressions. Like many pioneering books, Darwin's The Expression of Emotions in Man and Animals represents a flurry of novel and revolutionary, yet often inconsistent, ideas, which lend themselves to different readings. However, while the historical perspective Barrett provides is useful, the scientific conversation on emotion expressions has evolved since Darwin. Here, we briefly discuss why the two alternative explanations Barrett offers for the origins of emotion expressions-expressions as cultural symbols and/or as evolutionary byproducts-are both untenable in light of existing research. We also note that although evidence for our two-stage model is currently incomplete, our goal was not to tell a complete story. Instead, we sought to offer the best emerging explanation for the existing research and provide a path for future empirical work that can test it.