1998/01/01 by Sandra T. de Blois, Melinda A. Novak, Melanie Bond · 3 citations
Neuroscience · Psychology · #Memory and Neural Mechanisms #Child and Animal Learning Development #Primate Behavior and Ecology
paper · doi:10.1037/0735-7036.112.2.137
openalex publication_date 1998/01/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/06/11
The authors tested orangutans (Pongo pygmaeus) and squirrel monkeys (Saimiri sciureus) on object permanence tasks. In Experiment 1, orangutans solved all visible displacements and most invisible displacements except those involving movements into 2 boxes successively. In Experiment 2, performance of orangutans on double invisible displacements and control displacements (assessing simple strategies) was compared. Orangutans did not use the simple strategy of selecting the box visited last by the experimenter. Instead, poorer performance on double invisible displacements may have been related to increased memory requirements. In Experiment 3, squirrel monkeys were tested using the procedure of Experiment 1. Squirrel monkeys solved visible but did not comprehend invisible displacements. Results suggest that orangutans but not squirrel monkeys possess Stage 6 object permanence capabilities.