Dissociation between seeing and acting: insights from common marmosets (Callithrix jacchus).

Perception-based measures often reveal much earlier competencies than action-based approaches. We explored this phenomenon generally labeled as "knowledge dissociation" in 28 common marmoset monkeys (Callithrix jacchus) using a paradigm where subjects had to localize a food item dropped down an opaque tube. Experiments 1 and 2 assessed common marmoset monkeys' gravity bias in an action based version of the tubes task. Experiments 3 and 4 investigated whether marmosets' performance increases in an action-free task context where they simply look at objects falling down a tube. The results suggest that common marmosets have some intuition of continuity/solidity constraints when tested with perception based measures even though these principles do not appear to guide their search for falling objects.