Abstract
In infants, the posterior alpha EEG rhythm (6-9 Hz) has been found to index visual attention (Michel et al., 2015; Xie et al., 2018). Typically, during attention allocation to external stimuli, alpha attenuates, or desynchronizes, over occipital regions. The extent to which posterior infant alpha is modulated by learning across the first year of life is not well understood. Learning was predicted to increase posterior alpha desynchronization across ages. Six-month-old (n=26), 9-month-old (n=23), and 12-month-old (n=19) infants completed a short label learning session in which a group of novel computer-generated stimuli were verbally labeled with several individual names (“Boris”, “Jamie”, etc) while the other group of stimuli was labeled with a single category label (“Hitchel”). Before and after learning, occipital EEG was recorded while novel exemplars from both groups of objects, as well as untrained objects and faces, floated down the middle of the computer monitor, one at a time for 10 seconds each. Results showed significant occipital alpha desynchronization for 9- and 12-month-old infants relative to 6-month-old infants (ps<0.001) and response to faces relative to objects (ps<0.01). These results suggest that occipital alpha desynchronization in response to faces and objects begins between 6 to 9 months of age and may be more sensitive to faces compared to objects. These findings are in line with the timing of infant visual perceptual narrowing.