Great apes track hidden objects after changes in the objects' position and in subject's orientation

Area of Science:

• Primate cognition
• Comparative psychology
• Spatial memory

Background:

• Understanding spatial cognition in non-human primates is crucial for insights into the evolution of cognitive abilities.
• Previous research suggests differences in spatial task performance among great ape species.

Purpose of the Study:

• To investigate spatial memory and coding strategies in chimpanzees, bonobos, gorillas, and orangutans.
• To compare performance on rotation and translocation tasks, and assess the impact of displacement complexity.

Main Methods:

• Great apes were tested on invisible object displacement tasks involving cup rotations and translocations.
• Trials included no displacement, single displacement (rotation or translocation), and double displacement (both).
• Performance was analyzed to determine success rates and identify spatial coding strategies.

Main Results:

• All great ape species performed above chance across all conditions.
• Task difficulty increased with displacement complexity: no displacement < single displacement < double displacement.
• Chimpanzees (Pan troglodytes) significantly outperformed bonobos (Pan paniscus), gorillas (Gorilla gorilla), and orangutans (Pongo pygmaeus).
• No significant difference in performance was observed between rotation and translocation tasks.

Conclusions:

• Great apes utilize allocentric spatial coding, referencing external cues rather than egocentric self-centered cues.
• Chimpanzees exhibit the most proficient spatial memory among the studied great ape species.
• Findings contribute to understanding the cognitive evolution of spatial representation in primates.