This study investigated the effects of familiarization and attention on event-related potential (ERP) correlates of recognition memory in infants. Infants 4.5, 6, or 7.5 months of age were either familiarized with 2 stimuli that were used during later testing or presented 2 stimuli that were not used later. Then, infants were presented with a recording of Sesame Street to elicit attention or inattention and presented with familiar and novel stimuli. A negative ERP component over the frontal and central electrodes (Nc) was larger in the preexposure familiarization group for novel-than for familiar-stimulus presentations, whereas the Nc did not differ for the group not receiving a familiarization exposure. Spatial independent components analysis of the electroencephelogram and "equivalent current dipole" analysis were used to examine putative cortical sources of the ERP components. The cortical source of Nc was located in areas of prefrontal cortex and anterior cingulate cortex.Visual attention and recognition memory in infants are closely related. For example, infants demonstrate greater memory for events they were exposed to while in an attentive state than for events they were exposed to in an inattentive state (Frick & Richards, 2001;Richards, 1997). Events that have been partially encoded into memory or events that are novel elicit larger attention responses than those events that have been fully encoded (Bornstein, 1985;Fantz, 1961Fantz, ,1963. Infants show larger orienting responses to novel events than to those events that are familiar to them. Studies examining visual attention and recognition memory simultaneously can provide insight into the overall cognitive activity involved in an organism's adaptive responses to environmental information. The present study shows that attentionelicited event-related potential (ERP) responses differ as a function of the infant's familiarity with the stimuli and suggests that these effects are mediated by the prefrontal cortex of the brain.Several studies of infant recognition memory development have used the electroencephelogram (EEG) to measure ERPs related to recognition memory. ERPs are scalp voltage oscillations that are time locked with a specific physical or mental event (Fabiani, Gratton, & Coles, 2000;Picton et al., 2000). Courchesne, Ganz, and Norcia (1981) recorded ERP during an oddball procedure. They exposed 10 infants from 4 to 7 months of age to tachistoscopically presented slides of two unfamiliar female faces. One female face was presented on 88% of the trials (standard stimulus), and the other female face was presented on 12% of the trials (oddball stimulus). A negative component over the frontal and central electrodes with a latency of 700 ms, labeled Nc ("negative central"), was larger to the oddball stimulus than to the standard stimulus. A later occurring (latency = 1,360 ms) positive component followed both the infrequently and frequently presented stimuli. The authors concluded that the frequently presented stimulus was more familiar to t...

To examine the developmental course of look duration as a function of age and stimulus type, 14-to 52-week-old infants were shown static and dynamic versions of faces, Sesame Street material and achromatic patterns for 20 seconds of accumulated looking. Heart rate was recorded during looking and parsed into stimulus orienting, sustained attention, and attention termination phases of attention. Infants' peak look durations indicated that prior to 26 weeks there was a linear decrease with age for all stimuli. Older infants' look durations continued to decline for patterns but increased for Sesame Street and faces. Measures of heart rate change during sustained attention and the proportion of time spent in each phase of attention confirmed infants' greater engagement with the more complex stimuli.Infants' Attention to Patterned Stimuli: Developmental Change from 3 to 12 Months of Age Measures of visual attention obtained from habituation and selective looking (e.g., pairedcomparison; novelty preference) procedures have provided a wealth of information about the development of infants' sensory, perceptual, and cognitive capabilities (for reviews see Haith & Benson, 1998;Kellman & Banks, 1998). More recently, these procedures have become important in their own right with growing evidence that components of infants' attention during habituation and selective looking also provide information about the functioning and early development of the human information-processing system (see Bornstein, 1998;Colombo, 1993;Fagan, 1990;Hayne, 2004;McCall, 1994;Rose, Feldman, & Jankowski, 2004). The underlying reasoning is not new and is based on the assumption that the process of habituation represents a ubiquitous and elementary form of learning during which the infant constructs an internal representation (trace, or engram) of an external stimulus. As the infant's attention to the stimulus progresses and its representation becomes complete, his or her attention to it wanes. The subsequent presentation of a novel stimulus elicits a recovery of attention (dishabituation, or a novelty preference) as the infant presumably compares its features to the internal representation of the familiar stimulus, "recognizes" at some level that it is unrepresented or weakly represented in memory, and begins the process of trace construction once more (Sokolov, 1963). These same familiarization, comparison, and recognition processes are also presumed to occur without complete habituation, as infants will show visual preference for a novel stimulus even after fairly brief exposure to a standard (see Fagan,

In this study, we had 3 major goals. The 1st goal was to establish a link between behavioral and event-related potential (ERP) measures of infant attention and recognition memory. To assess the distribution of infant visual preferences throughout ERP testing, we designed a new experimental procedure that embeds a behavioral measure (paired comparison trials) in the modified-oddball ERP procedure. The 2nd goal was to measure infant ERPs during the paired comparison trials. Independent component analysis (ICA) was used to identify and to remove eye-movement components from the electroencephalographic data, thus allowing for the analysis of ERP components during paired comparison trials. The 3rd goal was to localize the cortical sources of infant visual preferences. Equivalent current dipole analysis was performed on the ICA components related to experimental events. Infants who demonstrated novelty preferences in paired comparison trials demonstrated greater amplitude Negative central ERP components across tasks than infants who did not demonstrate novelty preferences. Visual preference also interacted with attention and stimulus type. The cortical sources of infant visual preferences were localized to inferior and superior prefrontal cortex and to the anterior cingulate cortex.

In this article, we review research and theory on the development of attention and working memory in infancy using a developmental cognitive neuroscience framework. We begin with a review of studies examining the influence of attention on neural and behavioral correlates of an earlier developing and closely related form of memory (i.e., recognition memory). Findings from studies measuring attention utilizing looking measures, heart rate, and event-related potentials (ERPs) indicate significant developmental change in sustained and selective attention across the infancy period. For example, infants show gains in the magnitude of the attention related response and spend a greater proportion of time engaged in attention with increasing age (Richards and Turner, 2001). Throughout infancy, attention has a significant impact on infant performance on a variety of tasks tapping into recognition memory; however, this approach to examining the influence of infant attention on memory performance has yet to be utilized in research on working memory. In the second half of the article, we review research on working memory in infancy focusing on studies that provide insight into the developmental timing of significant gains in working memory as well as research and theory related to neural systems potentially involved in working memory in early development. We also examine issues related to measuring and distinguishing between working memory and recognition memory in infancy. To conclude, we discuss relations between the development of attention systems and working memory.

Psychological scientists have become increasingly concerned with issues related to methodology and replicability, and infancy researchers in particular face specific challenges related to replicability: For example, high-powered studies are difficult to conduct, testing conditions vary across labs, and different labs have access to different infant populations. Addressing these concerns, we report on a large-scale, multisite study aimed at (a) assessing the overall replicability of a single theoretically important phenomenon and (b) examining methodological, cultural, and developmental moderators. We focus on infants’ preference for infant-directed speech (IDS) over adult-directed speech (ADS). Stimuli of mothers speaking to their infants and to an adult in North American English were created using seminaturalistic laboratory-based audio recordings. Infants’ relative preference for IDS and ADS was assessed across 67 laboratories in North America, Europe, Australia, and Asia using the three common methods for measuring infants’ discrimination (head-turn preference, central fixation, and eye tracking). The overall meta-analytic effect size (Cohen’s d) was 0.35, 95% confidence interval = [0.29, 0.42], which was reliably above zero but smaller than the meta-analytic mean computed from previous literature (0.67). The IDS preference was significantly stronger in older children, in those children for whom the stimuli matched their native language and dialect, and in data from labs using the head-turn preference procedure. Together, these findings replicate the IDS preference but suggest that its magnitude is modulated by development, native-language experience, and testing procedure.