Exploration and learning in capuchin monkeys (Sapajus spp.): the role of action–outcome contingencies

Animals have a strong propensity to explore theenvironment. Spontaneous exploration has a great biologicalsignificance since it allows animals to discover andlearn the relation between specific behaviours and theirconsequences. The role of the contingency between actionand outcome for learning has been mainly investigated ininstrumental learning settings and much less in freeexploration contexts. We tested 16 capuchin monkeys(Sapajus spp.) with a mechatronic platform that allowedcomplex modules to be manipulated and to produce differentoutcomes. Experimental subjects could manipulatethe modules and discover the contingencies between theirown specific actions and the outcomes produced (i.e., theopening and lighting of a box). By contrast, Control subjectscould operate on the modules, but the outcomesexperienced were those performed by their pairedExperimental subjects (‘‘yoked-control’’ paradigm). In theexploration phase, in which no food reward was present,Experimental subjects spent more time on the board andmanipulated the modules more than Yoked subjects.Experimental subjects outperformed Yoked subjects in thefollowing test phase, where success required recalling theeffective action so to open the box, now baited with food.These findings demonstrate that the opportunity to experienceaction–outcome contingencies in the absence ofextrinsic rewards promotes capuchins’ exploration andfacilitates learning processes. Thus, this intrinsicallymotivated learning represents a powerful mechanismallowing the acquisition of skills and cognitive competencethat the individual can later exploit for adaptive purposes.