Data from: Heterochrony in chimpanzee and bonobo spatial memory development

Objectives: The emergence of human-unique cognitive abilities has been
linked to our species' extended juvenile period. Comparisons of
cognitive development across species can provide new insights into the
evolutionary mechanisms shaping cognition. This study examined the
development of different components of spatial memory, cognitive
mechanisms that support complex foraging, by comparing two species with
similar life history that vary in wild ecology: bonobos (Pan paniscus) and
chimpanzees (Pan troglodytes). Materials and methods: Spatial memory
development was assessed using a cross-sectional experimental design
comparing apes ranging from infancy to adulthood. Study 1 tested 73
sanctuary-living apes on a task examining recall of a single location
after a 1-week delay, compared to an earlier session. Study 2 tested their
ability to recall multiple locations within a complex environment. Study 3
examined a subset of individuals from Study 2 on a motivational control
task. Results: In Study 1, younger bonobos and chimpanzees of all ages
exhibited improved performance in the test session compared to their
initial learning experience. Older bonobos, in contrast, did not exhibit a
memory boost in performance after the delay. In Study 2, older chimpanzees
exhibited an improved ability to recall multiple locations, whereas
bonobos did not exhibit any age-related differences. In Study 3, both
species were similarly motivated to search for food in the absence of
memory demands. Discussion: These results indicate that closely related
species with similar life history characteristics can exhibit divergent
patterns of cognitive development, and suggests a role of socioecological
niche in shaping patterns of cognition in Pan.