The adult brain is endowed with mechanisms subserving enhanced processing of salient emotional and social cues. Stimuli associated with threat represent one such class of cues. Previous research suggests that preferential allocation of attention to social signals of threat (i.e. a preference for fearful over happy facial expressions) emerges during the second half of the first year. The present study was designed to determine the age of onset for infants' attentional bias for fearful faces. Allocation of attention was studied by measuring event-related potentials (ERPs) and looking times (in a visual paired comparison task) to fearful and happy faces in 5- and 7-month-old infants. In 7-month-olds, the preferential allocation of attention to fearful faces was evident in both ERPs and looking times, i.e. the negative central mid-latency ERP amplitudes were more negative, and the looking times were longer for fearful than happy faces. No such differences were observed in the 5-month-olds. It is suggested that an enhanced sensitivity to facial signals of threat emerges between 5 and 7 months of age, and it may reflect functional development of the neural mechanisms involved in processing of emotionally significant stimuli.

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The present study investigated whether facial expressions modulate visual attention in 7‐month‐old infants. First, infants’ looking duration to individually presented fearful, happy, and novel facial expressions was compared to looking duration to a control stimulus (scrambled face). The face with a novel expression was included to examine the hypothesis that the earlier findings of greater allocation of attention to fearful as compared to happy faces could be due to the novelty of fearful faces in infants’ rearing environment. The infants looked longer at the fearful face than at the control stimulus, whereas no such difference was found between the other expressions and the control stimulus. Second, a gap/overlap paradigm was used to determine whether facial expressions affect the infants’ ability to disengage their fixation from a centrally presented face and shift attention to a peripheral target. It was found that infants disengaged their fixation significantly less frequently from fearful faces than from control stimuli and happy faces. Novel facial expressions did not have a similar effect on attention disengagement. Thus, it seems that adult‐like modulation of the disengagement of attention by threat‐related stimuli can be observed early in life, and that the influence of emotionally salient (fearful) faces on visual attention is not simply attributable to the novelty of these expressions in infants’ rearing environment.

Several studies have shown that at 7 months of age, infants display an attentional bias toward fearful facial expressions. In this study, we analyzed visual attention and heart rate data from a cross‐sectional study with 5‐, 7‐, 9‐, and 11‐month‐old infants (Experiment 1) and visual attention from a longitudinal study with 5‐ and 7‐month‐old infants (Experiment 2) to examine the emergence and stability of the attentional bias to fearful facial expressions. In both experiments, the attentional bias to fearful faces appeared to emerge between 5 and 7 months of age: 5‐month‐olds did not show a difference in disengaging attention from fearful and nonfearful faces, whereas 7‐ and 9‐month‐old infants had a lower probability of disengaging attention from fearful than nonfearful faces. Across the age groups, heart rate (HR) data (Experiment 1) showed a more pronounced and longer‐lasting HR deceleration to fearful than nonfearful expressions. The results are discussed in relation to the development of the perception and experience of fear and the interaction between emotional and attentional processes.