Visual stimulus structure, visual system neural activity, and visual behavior in young human infants

In visual perception and information processing, a cascade of associations is hypothesized to flow from the structure of the visual stimulus to neural activity along the retinogeniculostriate visual system to behavior and action. Do visual perception and information processing adhere to this cascade near the beginning of life? To date, this three-stage hypothetical cascade has not been comprehensively tested in infants. In two related experiments, we attempted to expose this cascade in 6-month-old infants. Specifically, we presented infants with two levels of visual stimulus intensity, we measured electrical activity at the infant cortex, and we assessed infants' preferential looking behavior. Chromatic saturation provided a convenient stimulus dimension to test the cascade because greater saturation is known to excite increased activity in the primate visual system and is generally hypothesized to stimulate visual preference. Experiment 1 revealed that infants prefer (look longer) at the more saturated of two colors otherwise matched in hue and brightness. Experiment 2 showed increased aggregate neural cortical excitation in infants (and adults) to the more saturated of the same pair of colors. Thus, experiments 1 and 2 taken together confirm a cascade: Visual stimulation of relatively greater intensity evokes relatively greater levels of bioelectrical cortical activity which in turn is associated with relatively greater visual attention. As this cascade obtains near the beginning of life, it helps to account for early visual preferences and visual information processing.

Attention control in preterm and term 5-month-old infants: Cross-task stability increases with gestational age

Cross-task stability refers to performance consistency across different settings and measures of the same construct. Cross-task stability can help us understand developmental processes, including how risks such as preterm birth affect outcomes. We investigated cross-task stability of attention control in 32 preterm and 39 term infants. All infants had the same chronological age at time of testing (5 months) but varied in gestational age (GA) at birth (30-42 weeks). Infants completed an experimental attention following task with a researcher and a naturalistic play observation with their mothers. Both preterm and term infants demonstrated attention following in the experimental task. GA and flexibility of attention were related: the likelihood of no turn trials decreased with increasing GA. To evaluate cross-task stability, we compared attention performance in the experimental and naturalistic settings. Flexible attention shifts on the experimental task were positively related to attention to objects in the naturalistic observation. Furthermore, the association between flexible attention shifts on the experimental task and attention to objects in the naturalistic observation was moderated by GA. Our study provides initial evidence that the consolidation of attention control increases with GA. These findings highlight the value of comparing experimental and observational measures of attention.

Still-face redux: Infant responses to a classic and modified still-face paradigm in proximal and distal care cultures

Literature on infant emotion is dominated by research conducted in Western, industrialized societies where early socialization is characterized by face-to-face, vocal communication with caregivers. There is a dearth of knowledge of infant emotion in the context of social interaction outside of the visual and vocal modalities. In a three-population cross-cultural comparison, we used the still-face task to measure variation in behavior among infants from proximal care (practicing high levels of physical contact) communities in Bolivia and distal care (emphasizing vocal and visual interaction) communities in the U.S. and Fiji. In a modified version of the face-to-face still-face (FFSF), Study 1, infants in the U.S. and Fiji displayed the typical behavioral response to the still-face episode: increased negative affect and decreased social engagement, whereas infants in Bolivia showed no change. For tactile behavior, infants in Bolivia showed an increase in tactile self-stimulation from the interaction episode to the still-face episode, whereas U.S. infants showed no change. In Study 2, we created a novel body-to-body version of the still-face paradigm ("still-body") with infants in US and Bolivia, to mimic the near-constant physical contact Bolivian infants experience. The U.S. and Bolivian infant response was similar to Study 1: US infants showed decreased positive affect and increased negative affect and decreased social engagement from the interaction to the still-body episode and Bolivian infants showed no change. Notably, there were overall differences in infant behaviors between the two paradigms (FFSF and Still-Body). Infants in Bolivia and the U.S. showed increased positive facial affect during the FFSF paradigm in comparison with the Still-Body paradigm. Our results demonstrate the need for more globally representative developmental research and a broader approach to infant emotion and communication.

Evidence for Attentional Phenotypes in Infancy and Their Role in Visual Cognitive Performance

Infant visual attention rapidly develops during the first year of life, playing a pivotal role in the way infants process, learn, and respond to their visual world. It is possible that individual differences in eye movement patterns shape early experience and thus subsequent cognitive development. If this is the case, then it may be possible to identify sub-optimal attentional behaviors in infancy, before the emergence of cognitive deficit. In Experiment 1, a latent profile analysis was conducted on scores derived from the Infant Orienting with Attention (IOWA) task, a cued-attention task that measures individual differences in spatial attention and orienting proficiency. This analysis identified three profiles that varied substantially in terms of attentional efficiency. The largest of these profiles (“high flexible”, 55%) demonstrated functionally optimal patterns of attentional functioning with relatively rapid, selective, and adaptive orienting responses. The next largest group (“low reactive”, 39.6%) demonstrated low attentional sensitivity with slow, insensitive orienting responses. The smallest group (“high reactive”, 5.4%) demonstrated attentional over-sensitivity, with rapid, unselective and inaccurate orienting responses. A linear mixed effect model and growth curve analysis conducted on 5- to 11-month-old eye tracking data revealed significant stable differences in growth trajectory for each phenotype group. Results from Experiment 2 demonstrated the ability of attentional phenotypes to explain individual differences in general cognitive functioning, revealing significant between-phenotype group differences in performance on a visual short-term memory task. Taken together, results presented here demonstrate that attentional phenotypes are present early in life and predict unique patterns of growth from 5 to 11 months, and may be useful in understanding the origin of individual differences in general visuo-cognitive functioning.

Interactive coordination of currently depressed inpatient mothers and their infants during the postpartum period

In healthy mother-infant dyads, interactions are characterized by a pattern of matching and mismatching interactive states with quick reparation of mismatches into matches. In contrast, dyads in which mothers have postpartum depression show impaired mother-infant interaction patterns over the first few months of the infant's life. The majority of studies that have examined such interaction patterns have drawn on community samples rather than on depressed inpatient samples of mothers who were in a state of current depression at the time of assessment. To date, no study has investigated specific microanalytic patterns of interactive coordination between depressed German mothers and their infants using the Face-to-Face Still-Face paradigm (FFSF). The primary goal of this study was to evaluate specific patterns of dyadic coordination and the capacity for repairing states of miscoordination in an inpatient sample of postpartum currently depressed mothers and their infants as compared with a healthy control group. A sample of 28 depressed inpatient German mothers and their infants (age range = 1-8 months, M age = 4.06 months) and 34 healthy dyads (range = 1-8 months, M age = 3.89 months) were videotaped while engaging in the FFSF. A focus was placed on the play and reunion episodes. Compared with healthy dyads, dyads with depressed mothers showed less coordination of positive matched states and longer latencies when repairing interactive mismatching states into positive matched states. Clinical implications are discussed.

Information processing efficiency and regulation at five months

Infants with short look durations are generally thought to have better attentional capabilities due to their efficient information processing. Although effortful attention is considered a key component of developing regulatory abilities, little is known about the relation between speed and efficiency of processing and self-regulation. In this study, 5-month-old infants with shorter look duration had greater EEG power values than infants with longer look duration during baseline, as well as during a distressing task and a post-distress attentional processing task. These short looking infants also demonstrated higher heart rate, relative to long looking infants, during post-distress information processing. Behaviorally the two groups differed in the amount of distraction during distress. These data provide evidence for an association between the efficiency of information processing and beginning regulatory abilities in early infancy.

The early development of visual attention and its implications for social and cognitive development

Looking behavior plays a crucial role in the daily life of an infant and forms the basis for cognitive and social development. The infant's visual attentional systems undergo rapid development during the first few months of life. During the last decennia, the study of visual attentional development in infants has received increasing interest. Several reliable measures to investigate the early development of attentional processes have been developed, and currently a number of new methods are giving fresh impetus to the field. Research on overt and covert as well as exogenously and endogenously controlled attention shifts is presented. The development of gaze shifts to peripheral targets, covert attention, and visual scanning behavior is treated. Whereas most attentional mechanisms in very young infants are thought to be mediated mainly by subcortical structures, cortical mechanisms become increasingly more functional throughout the first months. Different accounts of the neurophysiological underpinnings of attentional processes and their developmental changes are discussed. Finally, a number of studies investigating the implications of attentional development for early cognitive and social development are presented.