I LEARNED FROM WHAT YOU DID : RETRIEVING RULES LEARNED BY OBSERVATION MONFARDINI E.*, BROVELLI A., BOUSSAOUD D., TAKERKART S., WICKER B. Institut de Neurosciences Cognitives de la Méditerranée (INCM), CNRS UMR 6193, Marseille, France

Observational/social learning improves human adaptability and allows individuals to acquire a vast store of useful knowledge without incurring the costs of discovering and testing this knowledge themselves (Castro & Toro, 2004). In this study, we used fMRI to explore the possibility that social learning is subserved by specific neural structures linking environmental information (visual stimuli) with observation of another’s action to generate an internal representation of an arbitrary rule. Several fMRI studies have explored the neural substrates of retrieval of rules learned by trial and error (e.g. Bunge et al, 2004), but no studies to date have addressed the issue of whether this rule retrieval process could be influenced by the way the rule was acquired. Here, we compare brain activations related to the retrieval of arbitrary visuo-motor associations learned either by trial and error or by observation. Prior to fMRI scanning, 11 adult subjects were asked to learn a set of visuomotor associations by trial and error and another set by observation of an expert actor. During fMRI scanning, subjects were requested to retrieve the associations learned in either ways. The conjunction analysis between the trial and error and observational learning conditions reveals common brain activations in the ventral and dorsal lateral prefrontal cortex (LatPFC), in the superior parietal lobe and in the pre-SMA. This common network of activated brain areas is therefore involved both when the rule was acquired through the subject’s own experience and when the rule was is acquired by observing another’s experience. This suggests the existence of a mirrorlike system responsible for the storage of rules learned either by trial and error or by observation of another’s actions. Learning would thus be mediated by neuronal activity changes within a similar brain network, either in trial and error learning or observational learning. These neuronal changes would lead to the storage, within the same network, of stimulus-response mappings. One brain area, the pars triangularis of the right prefrontal cortex (BA45/46) is specifically recruited when the rule has been learned by observation, plausibly demonstrating that learning about the motivational value of actions may access this system, which subsequently allows individuals to improve their own decisions.

Figure 1. (A) Right lateral prefrontal region exhibiting Learning_by_Observation effects (Talairach coordinates: 42 20 18). (B) Percent change in bold signals observed in this region for Trial_&_Error (TE, blue), Learning_by_Observation (LeO, green), control condition (CONT, red) and movies showing an actor’s hand performing the visuo-motor rules (Films, light blue). Error bars indicate standard error. The right lateral PFC shows a significantly stronger BOLD response during movies and LeO conditions than during TE (film-TE, p= 0,006; LeO-TE, p=0,01). No significant difference was found between LeO and movies conditions (p= 0,6).

References: Castro L, Toro M (2004) The evolution of culture: From primate social learning to human culture. Proc. Natl. Acad. Sci. 101: 10235-10240. Bunge SA (2004). How we use rules to select actions: a review of evidence from cognitive neuroscience. Cogn Affect Behav Neurosci. 4: 564-579.