Independent Evolution of Similar Complex Cognitive Skills: The Importance of Embodied Degrees of Freedom

摘要

Recent years have seen ackno wledgment from a number of researchers that similarities appear to exist in complex cognitive skills of distantly related species – most notably in corvids, parrots, delphinids, and great apes. Discoveries on complex cognitive skills in common hold the promise of interesting and fruitful new perspectives on cognitio n. That said, some theoretical approaches seem largely to be lacking. We draw attention to the importance of pre-existing constraints on and freedoms of the evolving animal, which might prove as important as external selective pressures in understanding the evolution of cognition. To elucidate our point, we briefly describe one contemporary cognitive-science approach to cognition. Accounts on cognitive evolution both in behavioral ecology and animal cognition are often hampered by simplistic input-output-based views on cognition. Cognition – in particular complex cognition – may influence animal behaviors in ways that cannot be captured by a purely selectionist account. We discuss the evolutionary processes underlying independently evolved yet similar characters. We highlight the importance of the difference between parallel and convergent evolution in understanding whether complex cognition arises repeatedly only through similar selective pressures; or whether underlying, previously evolved structures are crucial for the occurrence of cognitive similarities. In conclusion we suggest that the developmental sequences leading to apparently similar cognitive skills req uire further investigatio n to reveal the evolutio nary processes behind them. Our aim is not one of providing ultimate answers to the questio ns we raise; instead, we draw attention to their existence, the better that they may be addressed.