During development internal models of the sensory world must be acquired which have to be continuously adapted later. We used event-related potentials (ERP) to test the hypothesis that infants extract crossmodal statistics implicitly while adults learn them when task relevant. Participants were passively exposed to frequent standard audio-visual combinations (A1V1, A2V2, p=0.35 each), rare recombinations of these standard stimuli (A1V2, A2V1, p=0.10 each), and a rare audio-visual deviant with infrequent auditory and visual elements (A3V3, p=0.10). While both six-month-old infants and adults differentiated between rare deviants and standards involving early neural processing stages only infants were sensitive to crossmodal statistics as indicated by a late ERP difference between standard and recombined stimuli. A second experiment revealed that adults differentiated recombined and standard combinations when crossmodal combinations were task relevant. These results demonstrate a heightened sensitivity for crossmodal statistics in infants and a change in learning mode from infancy to adulthood.

22While adults have to continuously adapt their internal representations of the sensory world, infants 23 need to first acquire these models. We used event-related potentials to test the hypothesis that infants 24 extract crossmodal statistics implicitly while adults learn them when task relevant. Six-month-old 25 infants and adults were passively exposed to frequent standard audio-visual combinations (A1V1, 26 A2V2, p=0.35 each), rare recombinations of the standard stimuli (A1V2, A2V1, p=0.10 each), and a rare 27 deviant audio-visual combination with an infrequent auditory and visual element (A3V3, p=0.10). 28While both infants and adults differentiated between rare deviants and standards at early processing 29 stages, only infants discriminated standards from recombined stimuli at a later processing stage. A 30 second experiment revealed that adults discriminated recombined from standard combinations only 31 when crossmodal combinations were task relevant. These results demonstrate a heightened sensitivity 32 for crossmodal statistics in infants and a change in learning mode from infancy to adulthood.

During development internal models of the sensory world must be acquired which have to be continuously adapted later. We used event-related potentials (ERP) to test the hypothesis that infants extract crossmodal statistics implicitly while adults learn them when task relevant. Participants were passively exposed to frequent standard audio-visual combinations (A1V1, A2V2, p=0.35 each), rare recombinations of these standard stimuli (A1V2, A2V1, p=0.10 each), and a rare audio-visual deviant with infrequent auditory and visual elements (A3V3, p=0.10). While both six-month-old infants and adults differentiated between rare deviants and standards involving early neural processing stages only infants were sensitive to crossmodal statistics as indicated by a late ERP difference between standard and recombined stimuli. A second experiment revealed that adults differentiated recombined and standard combinations when crossmodal combinations were task relevant. These results demonstrate a heightened sensitivity for crossmodal statistics in infants and a change in learning mode from infancy to adulthood.