Abstract

The ability to form concepts as an abstraction and organization of the common elements shared by different stimuli is a basic cognitive ability that lies at the core of human intelligence. In adults, the ventromedial prefrontal cortex-hippocampus circuits are activated during concept acquisition. It is well known that the prefrontal cortex undergoes profound changes during postnatal development likely associated to differences in the children and adults concept acquisition. Interestingly, little is known about concept formation during postnatal development. We assessed concept acquisition in prelexical children (5 yo) and compared it to adult acquisition using a feedback based task. Subjects had to predict the weather (sunny/rainy) associated to each of 8 different visuospatial patterns, composed by 2 out of 4 geometrical figures (Kumaran 2009). We used two versions of the task: a spatial cue-outcome association and a non spatial cue-outcome association in two different groups of subjects. After the subject response, an immediate correct/incorrect feedback was presented. The explicit knowledge of the association was assessed using a non-verbal test. In agreement with previous studies, we found that adults exhibit a fast learning for both, spatial and non-spatial task versions, and the acquisition of explicit knowledge of the task’s rule was associated to their outcome improvement. On the contrary, children did not improve the overall performance in the spatial and non-spatial cueoutcome association tasks, although improvement in the performance for individual cues was observed, likely reflecting memory for single patterns. No differences were observed between the spatial and non spatial versions of the task. Consistent with these results, children did not develop an explicit knowledge of the association patterns (spatial and non-spatial). In conclusion, prelexical children showed an inflexible, unaware learning, likely indicating some form of implicit memory.