Is there an evolutionary trade-off between quality signaling and social recognition?

Lay Summary Why do humans lack extravagant peacock-like signals? Why do so many animals not recognize the individuals around them? Here, we suggest that there may be evolutionary trade-off between elaborate quality signals and social recognition. The framework we propose for integrating studies of signals and social recognition provides a road map for future work and helps explain why so many species living in stable groups, such as primates, tend to lack elaborate signaling traits.To successfully navigate their social environments animals need to assess conspecifics. Quality signals and social recognition are 2 assessment strategies that animals employ to evaluate potential rivals or mates. Despite substantial research on both assessment strategies, relatively little work has addressed how quality signals and social recognition interact. Here, we propose that quality signals and social recognition have an antagonistic evolutionary relationship, building on earlier assertions by Sievert Rohwer (American Zoologist, 1982). Both quality signals and social recognition provide animals access to information about conspecifics, allowing them to avoid costly confrontations or choose appropriate partners. We assert that, although the information gleaned from quality signals or social recognition overlaps, the processes by which information is acquired are distinct. Therefore, selection that favors quality signaling will lead to elaboration of signaling traits while disfavoring the elaboration of traits used in social recognition such as identity signals, learning, and memory. We first outline testable predictions for the hypothesis that quality signals and social recognition are antagonistic on evolutionary timescales, and we then explore its broader ramifications for understanding the distribution of signals and social recognition across taxa. Notably, the framework we propose emphasizes rarely considered factors such as body size that may tip the balance between the costs and benefits of each assessment strategy. Finally, we highlight the potential for important feedback between social assessment strategy and a species' socioecology.