From extant to extinct: The role of experiments and interdisciplinary inferences in studying cognitive and language evolution

This article evaluates the role of experiments and interdisciplinary inferences in the field of language evolution and, more broadly, studies of cognitive evolution. Namely, we assess the inferences made from experiments on extant species about the evolution of extinct ones. We concentrate on the field of language evolution research as a case study of research on cognitive evolution. Specifically, we look at inferences from experiments in three major approaches in language evolution research: comparative psychology, cognitive archaeology, and experimental semiotics. For each approach, we first explain the overall methods they employ, then we summarize important inferences from experimental studies in these fields, and finally, we evaluate to what degree these inferences can be extended to characterizing the cognitive abilities of extinct hominins. Finally, we discuss the role of experimental work for interdisciplinary theory-building in language evolution research and challenges regarding the epistemological commensurability of different approaches. We then propose solutions for increasing the ecological validity and epistemological alignment of experimental investigations of the study of cognitive evolution. • We assess to what extent experimental insights from extant species apply to extinct ones. • We assess inferences from experiments in comparative psychology, cognitive archaeology, and experimental semiotics. • Different experimental approaches in language evolution face the same challenges. • Epistemological alignment is necessary for a sound dialogue between approaches. • Data on extant species can offer insights for inferring ancient cognition but also faces limitations.