Deferred imitation in 18-month-olds from two cultural contexts: The case of Cameroonian Nso farmer and German-middle class infants

Imitative learning has been described in naturalistic studies for different cultures, but lab-based research studying imitative learning across different cultural contexts is almost missing. Therefore, imitative learning was assessed with 18-month-old German middle-class and Cameroonian Nso farmer infants – representing two highly different eco-cultural contexts associated with different cultural models, the psychological autonomy and the hierarchical relatedness – by using the deferred imitation paradigm. Study 1 revealed that the infants from both cultural contexts performed a higher number of target actions in the deferred imitation than in the baseline phase. Moreover, it was found that German middle-class infants showed a higher mean imitation rate as they performed more target actions in the deferred imitation phase compared with Cameroonian Nso farmer infants. It was speculated that the opportunity to manipulate the test objects directly after the demonstration of the target actions could enhance the mean deferred imitation rate of the Cameroonian Nso farmer infants which was confirmed in Study 2. Possible explanations for the differences in the amount of imitated target actions of German middle-class and Cameroonian Nso farmer infants are discussed considering the object-related, dyadic setting of the imitation paradigm with respect to the different learning contexts underlying the different cultural models of learning.     

Electrophysiological evidence for modulation of lexical processing after repetitive exposure to foreign phonotactic rules

In two experiments we investigate how repeated exposure to native and non-native phonotactic regularities alters the N400, an event-related potential related to lexico-semantic access. Participants underwent a Passive Listening (Experiment 1) or a Categorization Training (Experiment 2) for monosyllabic pseudowords over 3 days. During Passive Listening participants solely listened to the stimuli while for Categorization Training they learned to assign items to two arbitrary categories by feedback. Notably, this task did not rely on phonotactic regularities. Before training, N400 was larger for legal compared to illegal items. Over the 3-day exposure Passive Listening yielded a significant decrease in N400-amplitude for illegal pseudowords, however, this effect was abolished and partially inverted by the Categorization Training. We suggest the decrease in N400-amplitude indicates more efficient discrimination between native and non-native pseudowords since only the former are potential lexical candidates. On the contrary, Categorization Training introduces a ‘protosemantic’ context overriding prelexical selection processes.