The Development of Sensorimotor Cognition in Common Ravens (Corvus corax) and its Comparative Evolution

Abstract

Evolution involves developmental change. Species comparisons play an important role in comparative cognition because they can uncover common patterns and shared principles in cognitive evolution. Developmental studies reveal foundational elements of cognitive abilities and how they are constructed and integrated.Sensorimotor cognition is such a key element that forms the foundation for later-developing cognitive skills, yet little is known about its development in animals. This study uses 37 behaviors and tasks to investigate the development of Piagetian sensorimotor abilities in five young ravens (Corvus corax) from ages two to eleven weeks. Their developmental pattern largely mirrored that of twelve other bird and mammal species, albeit at a markedly accelerated rate. They reached the final sensorimotor stage, which to date has been shown only in great apes. The onset and sequence of sensorimotor development was identical for all species. Absolute number of neurons in the pallium and rest of brain was associated with achieving a higher stage across these species. This was not the case for absolute or relative brain mass, or number of neurons in the cerebellum or whole brain. We discuss the independent evolution of sensorimotor cognition and the importance of developmental pace and pattern therein. These findings show that the study of sensorimotor development is a useful tool for comparative cognition research.

Ravens parallel great apes in physical and social cognitive skills

“…These findings support the prediction that ravens undergo a relatively rapid cognitive development. They further expand recent results on single cognitive skills and sensorimotor development 68 , 72 in ravens to the physical cognitive scales of Causalities and Quantities and the manifold domain of social cognition. For instance, Schloegl and colleagues 77 , combining natural observations and behavioural experiments, showed that ravens, shortly after fledging (between 8–15 weeks of age), started to follow the gaze (look where others look) of a conspecific and a human experimenter.…”

“…If this explanation were true, we would have expected to find no differences between any tested physical and social cognitive scale across the four different time points, but this was not the case (see Table S4). In addition, recent studies on the development of gaze following skills 77 and sensorimotor abilities of ravens 72 showed that the general developmental pace is very fast compared to that of other bird and mammal species.…”

“…This rapid developmental phase stands in stark contrast to the much slower developmental pace in different species of psittacines 69 , 70 , which are also renowned for their sophisticated cognitive skills (e.g., 49 , 71 ). Similarly, a recent qualitative comparison of the development of Piagetian sensorimotor abilities across two bird and eleven mammal species (one corvid, one psittacine, five monkey, four great ape, and two carnivore species) showed that the developmental pace of ravens was markedly accelerated compared to that observed in the other species while the general developmental pattern was relatively similar 72 . This study, although only qualitative, marks a new trend in Cognitive Development since comparative research has traditionally been biased towards investigations of the cognitive development of human and non-human primates only 73 , 74 .…”

“…To address this question, we compared the performance of all individuals across four different time points: four months of age, eight months of age, twelve months of age, and 16 months of age. Based on the existing studies of cognitive development in ravens 68 , 72 , 77 , we predicted to find a relatively rapid development across cognitive scales and the four investigated time points. Do ravens match great apes’ cognitive abilities?…”

Individual and social factors affecting the ability of American crows to solve and master a string pulling task

“…Despite these caveats, there are numerous studies supporting brain volume as a predictor of cognitive ability. Recent research has emerged demonstrating the importance of neuronal counts over other brain‐related metrics (such as relative brain volume or cortex/pallium mass) in predicting a species’ cognitive capability (Herculano‐Houzel, ; Jacobs, Kabadayi, & Osvath, ; Jardim‐Messeder et al, ), with brain size being an appropriate predictor of neuron number (Marhounová, Kotrschal, Kverková, Kolm, & Němec, ). Additionally, a close association has been found between brain size and neuron count for the regions in the brain involved with cognition, such as the telencephalon (Marhounová et al, ).…”