Abstract
Selective attention filters available environmental information for which is further processed and the subject of subsequent cognitive or behavioral action. Spatial cueing studies, designed to measure the allocation of selective attention, have shown that adults produce saccadic eye movements with shorter latencies when they are cued indicating facilitation of attentional selection (Adler, Bala, & Krauzlis, 2002). A recent study with 3-month-old infants’ has shown that their saccadic latencies in a similar spatial cueing task are sensitive to prior birth experience (Adler & Wong-Kee-You, 2015), with caesarean section delivered infants exhibiting slower latencies to localize the cued target than those born vaginally. The present study addressed whether the attentional effect of birth experience observed in infants was transient or more permanent. To this end, a peripheral cue was either presented or not at one of two possible locations 5.5° to the left or right of center for 150 msec, followed randomly between 500 to 1000 msec later by either a target at the cued location or a target and distractor for 1500 msec. Results indicated that adults delivered by caesarean section and vaginally exhibited the same overall pattern of saccadic performance across cueing conditions. Similar to infants, however, caesarean section delivered adults had slower latencies than those delivered vaginally. One possible explanation is that the caesarean section impacts bottom-up attention, requiring an over-reliance on the top-down system. Consistent with this possibility, caesarean section delivered adults also exhibit more incorrect anticipatory saccades than vaginally delivered adults. Neurally, the birth process is thought to lower serotonin levels leading to differentiation of the somatosensory cortex (Toda et al., 2013) – a cascade that might not occur during caesarean section. In sum, the findings indicate that the development of attentional mechanisms is not static, as generally proposed, but influenced by early experiences that persist into adulthood.
Acknowledgement: The Hallward Fund of the Toronto Foundation