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  • Previous research has shown that spatial selective

    2018-10-25

    Previous research has shown that spatial selective attention and memory are mechanistically linked early in life (Markant and Amso, 2013), suggesting that it may be important to consider the interactive effects of selective attention, memory, and SES rather than examine the impact of SES on attention and memory separately. Selective attention involves modulation of visual carboxypeptidase a activity, with enhanced processing of attended stimuli and concurrent suppression of competing information (Desimone and Duncan, 1995; Gandhi et al., 1999; Kastner et al., 1999). This coupled target enhancement and distractor suppression improves the quality of attended object representations in visual cortical regions and supports enhanced visual processing (Carrasco, 2011, 2013; Zhang et al., 2011). Our work is based on the hypothesis that this reduced noise in the signal for the attended object in visual cortex (Zhang et al., 2011) also improves memory encoding for the target object. We capitalized on the spatial cueing task (Posner, 1980) to study the role of these spatial selective attention dynamics in early learning and memory. In this task, attention is engaged at a central location while a cue appears in the periphery. After a delay, a target appears in the cued location or in the opposite, noncued location (Fig. 1). When the cue-target delay is short (<250ms), orienting is facilitated to the previously cued location (Posner and Cohen, 1984; Posner, 1980). However, a longer cue-target delay (>250ms) elicits suppression at the cued location and biases orienting to the noncued location, an effect known as inhibition of return (IOR; Posner et al., 1985). This task can thus be used to compare orienting mechanisms that differentially engage the suppression component of selective attention. Both facilitation and IOR elicit attention at a target location, but only IOR involves both attention at the target location and suppression at the previously cued location. We previously asked whether engaging facilitation versus IOR orienting mechanisms during encoding supported differential learning during infancy. Infants viewed objects in the cued or noncued locations during an initial spatial cueing/encoding phase. We assessed infants’ subsequent memory for these objects based on looking times to novel objects relative to the familiar target objects. Infants’ memory was enhanced in the context of IOR orienting involving distractor suppression relative to basic orienting (facilitation) or a baseline condition with no attention manipulation (Markant and Amso, 2013). An adult fMRI study using a similar IOR design further demonstrated that suppression of visual cortex activity associated with the previously cued location predicted enhanced recognition memory performance (Markant et al., 2015b). This work demonstrated that engaging spatial selective attention supported enhanced memory across development. However, we were unable to examine interactive effects of selective attention, memory, and SES during infancy due to relatively small sample sizes in each study. As such, in the present study we re-analyzed data from these studies with a focus on relating SES and recognition memory in the contexts of facilitation versus IOR orienting mechanisms. In a similar paradigm adapted for children and adolescents (Markant and Amso, 2014), engaging selective attention (IOR) during encoding boosted recognition memory performance and mitigated the effects of lower IQ on recognition memory. When cueing elicited basic orienting (facilitation) during encoding, IQ was the only predictor of recognition memory. In contrast, engaging selection with concurrent suppression (IOR) during encoding improved memory performance among children with lower IQs (Markant and Amso, 2014). These findings raise the possibility that engaging spatial selective attention during encoding may similarly buffer memory from the adverse effects of low SES during infancy. Distractor suppression may support a higher-quality signal in the IOR condition (Markant et al., 2015b; Zhang et al., 2011), which in turn may reduce the load on weaker learning and memory skills among infants from lower SES environments.