Examining infants' visual paired comparison performance in the US and rural Malawi.

Measures of attention and memory were evaluated in 6- to 9-month-old infants from two diverse contexts. One sample consisted of African infants residing in rural Malawi (N = 228, 118 girls, 110 boys). The other sample consisted of racially diverse infants residing in suburban California (N = 48, 24 girls, 24 boys). Infants were tested in an eye-tracking version of the visual paired comparison procedure and were shown racially familiar faces. The eye tracking data were parsed into individual looks, revealing that both groups of infants showed significant memory performance. However, how a look was operationally defined impacted some-but not other-measures of infant VPC performance. RESEARCH HIGHLIGHTS: In both the US and Malawi, 6- to 9-month-old infants showed evidence of memory for faces they had previously viewed during a familiarization period. Infant age was associated with peak look duration and memory performance in both contexts. Different operational definitions of a look yielded consistent findings for peak look duration and novelty preference scores-but not shift rate. Operationalization of look-defined measures is an important consideration for studies of infants in different cultural contexts.

The impact of face masks on infants' learning of faces: An eye tracking study.

This preregistered study examined how face masks influenced face memory in a North American sample of 6- to 9-month-old infants (N = 58) born during the COVID-19 pandemic. Infants' memory was tested using a standard visual paired comparison (VPC) task. We crossed whether or not the faces were masked during familiarization and test, yielding four trial types (masked-familiarization/masked-test, unmasked-familiarization/masked-test, masked-familiarization/unmasked-test, and unmasked-familiarization/unmasked-test). Infants showed memory for the faces if the faces were unmasked at test, regardless of whether or not the face was masked during familiarization. However, infants did not show robust evidence of memory when test faces were masked, regardless of the familiarization condition. In addition, infants' bias for looking at the upper (eye) region was greater for masked than unmasked faces, although this difference was unrelated to memory performance. In summary, although the presence of face masks does appear to influence infants' processing of and memory for faces, they can form memories of masked faces and recognize those familiar faces even when unmasked.

The association between plasma choline, growth and neurodevelopment among Malawian children aged 6-15 months enroled in an egg intervention trial.

Choline is an essential micronutrient that may influence growth and development; however, few studies have examined postnatal choline status and children's growth and development in low- and middle-income countries. The aim of this observational analysis was to examine associations of plasma choline with growth and development among Malawian children aged 6-15 months enrolled in an egg intervention trial. Plasma choline and related metabolites (betaine, dimethylglycine and trimethylamine N-oxide) were measured at baseline and 6-month follow-up, along with anthropometric (length, weight, head circumference) and developmental assessments (the Malawi Developmental Assessment Tool [MDAT], the Infant Orienting with Attention task [IOWA], a visual paired comparison [VPC] task and an elicited imitation [EI] task). In cross-sectional covariate-adjusted models, each 1 SD higher plasma choline was associated with lower length-for-age z-score (-0.09 SD [95% confidence interval, CI -0.17 to -0.01]), slower IOWA response time (8.84 ms [1.66-16.03]) and faster processing speed on the VPC task (-203.5 ms [-366.2 to -40.7]). In predictive models, baseline plasma choline was negatively associated with MDAT fine motor z-score at 6-month follow-up (-0.13 SD [-0.22 to -0.04]). There were no other significant associations of plasma choline with child measures. Similarly, associations of choline metabolites with growth and development were null except higher trimethylamine N-oxide was associated with slower information processing on the VPC task and higher memory scores on the EI task. In this cohort of children with low dietary choline intake, we conclude that there were no strong or consistent associations between plasma choline and growth and development.

A new perspective on the role of physical salience in visual search: Graded effect of salience on infants' attention.

We tested 6- and 8-month-old White and non-White infants (N = 53 total, 28 girls) from Northern California in a visual search task to determine whether a unique item in an otherwise homogeneous display (a singleton) attracts attention because it is a unique singleton and "pops out" in a categorical manner, or whether attention instead varies in a graded manner on the basis of quantitative differences in physical salience. Infants viewed arrays of four or six items; one item was a singleton and the other items were identical distractors (e.g., a single cookie and three identical toy cars). At both ages, infants looked to the singletons first more often, were faster to look at singletons, and looked longer at singletons. However, when a computational model was used to quantify the relative salience of the singleton in each display-which varied widely among the different singleton-distractor combinations-we found a strong, graded effect of physical salience on attention and no evidence that singleton status per se influenced attention. In addition, consistent with other research on attention in infancy, the effect of salience was stronger for 6-month-old infants than for 8-month-old infants. Taken together, these results show that attention-getting and attention-holding in infancy vary continuously with quantitative variations in physical salience rather than depending in a categorical manner on whether an item is unique. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Infant Eye Gaze While Viewing Dynamic Faces.

Research using eye tracking methods has revealed that when viewing faces, between 6 to 10 months of age, infants begin to shift visual attention from the eye region to the mouth region. Moreover, this shift varies with stimulus characteristics and infants' experience with faces and languages. The current study examined the eye movements of a racially diverse sample of 98 infants between 7.5 and 10.5 months of age as they viewed movies of White and Asian American women reciting a nursery rhyme (the auditory component of the movies was replaced with music to eliminate the influence of the speech on infants' looking behavior). Using an analytic approach inspired by the multiverse analysis approach, several measures from infants' eye gaze were examined to identify patterns that were robust across different analyses. Although in general infants preferred the lower regions of the faces, i.e., the region containing the mouth, this preference depended on the stimulus characteristics and was stronger for infants whose typical experience included faces of more races and for infants who were exposed to multiple languages. These results show how we can leverage the richness of eye tracking data with infants to add to our understanding of the factors that influence infants' visual exploration of faces.

Robust data and power in infant research: A case study of the effect of number of infants and number of trials in visual preference procedures.

As in many areas of science, infant research suffers from low power. The problem is further compounded in infant research because of the difficulty in recruiting and testing large numbers of infant participants. Researchers have been searching for a solution and, as illustrated by this special section, have been focused on getting the most out of infant data. We illustrate one solution by showing how we can increase power in visual preference tasks by increasing the amount of data obtained from each infant. We discuss issues of power and present work examining how, under some circumstances, power is increased by increasing the precision of measurement. We report the results of a series of simulations based on a sample of visual preference task data collected from three infant laboratories showing how more powerful research designs can be achieved by including more trials per infant. Implications for infant procedures in general are discussed.

Visual short-term memory for overtly attended objects during infancy.

We investigated limitations in young infants' visual short-term memory (VSTM). We used a one-shot change detection task to ask whether 4- and 8.5-month-old infants (N = 59) automatically encode fixated items in VSTM. Our task included trials that consisted of the following sequence: first a brief (500 ms) presentation with a sample array of two items, next a brief (300 ms) delay period with a blank screen, and finally a test array (2,000 ms) identical to the sample array except that the color of one of the two items is changed. In Experiment 1, we induced infants to fixate one item by rotating it during the sample (the other item remained stationary). In Experiment 2, none of the items rotated. In both experiments, 4-month-old infants looked equally at the fixated item when it did and did not change color, providing no evidence that they encoded in VSTM the fixated item. In contrast, 8.5-month-old infants in Experiment 1 preferred the fixated item when it changed color from sample to test. Thus, 4-month-old infants do not appear to automatically encode fixated items in VSTM.

Early Child Development Outcomes of a Randomized Trial Providing 1 Egg Per Day to Children Age 6 to 15 Months in Malawi.

BACKGROUND: Eggs are a rich source of nutrients important for brain development, including choline, riboflavin, vitamins B-6 and B-12, folate, zinc, protein, and DHA. OBJECTIVE: Our objective was to evaluate the effect of the consumption of 1 egg per day over a 6-mo period on child development. METHODS: In the Mazira Project randomized controlled trial, 660 children aged 6-9 mo were randomly allocated into an intervention or control group. Eggs were provided to intervention households during twice-weekly home visits for 6 mo. Control households were visited at the same frequency. At enrollment, blinded assessors administered the Malawi Developmental Assessment Tool (MDAT), and 2 eye-tracking tasks using a Tobii-Pro X2-60 eye tracker: a visual paired comparison memory task and an Infant Orienting with Attention task. At endline, 6-mo later, blinded assessors administered the MDAT and eye-tracking tasks plus an additional elicited imitation memory task. RESULTS: At endline, intervention and control groups did not significantly differ in any developmental score, with the exception that a smaller percentage of children were delayed in fine motor development in the intervention group (10.6%) compared with the control group (16.5%; prevalence ratio: 0.59, 95% CI: 0.38-0.91). Among 10 prespecified effect modifiers for the 8 primary developmental outcomes, we found 7 significant interactions demonstrating a consistent pattern that children who were less vulnerable, for example, those with higher household wealth and maternal education, showed positive effects of the intervention. Given multiple hypothesis testing, some findings may have been due to chance. CONCLUSION: The provision of 1 egg per day had no overall effect on child development in this population of children, however, some benefits may be seen among children in less vulnerable circumstances. This trial was registered at clinicaltrials.gov as NCT03385252.

Habit2: A stand-alone software solution for presenting stimuli and recording infant looking times in order to study infant development.

Many aspects of infant development are assessed using infant looking times to visual and audiovisual stimuli. In this article, we describe a stand-alone software package that allows simultaneous stimulus presentation to infants and recording of their looking times via a keypress by a human observer. The software was developed to run both on 64-bit Intel-based Macs running Mac OS/X 10.10 (Yosemite) or later and on 64-bit Windows 7 and 10. It can present a variety of visual and/or auditory stimuli; is customizable with respect to how trials are initiated, how trial lengths are defined, and the phases of the experiment; and can be used to record looking times online or after the fact, as well as to assess the reliability of coding. The software is freely available at http://habit.ucdavis.edu.

High-precision visual long-term memory in children with high-functioning autism.

Domain-general theories of autism rest on evidence that the disorder impacts not only social communication skills but also nonsocial functions such as memory. Yet recognition memory deficits have been inconsistently documented, especially for stimuli other than faces and sentences. Here we tested school-age children with high-functioning autism (ASD) and IQ, and age-matched comparison children on a visual long-term memory task involving more than 100 photographs of objects, faces, cats, houses, and abstract stimuli. Children viewed each photograph for 2 s. After a 10-min filled delay, we assessed recognition memory for object category as well as for specific exemplars. Data supported the presence of a high-capacity and high-precision visual memory in children with ASD. Both category memory and exemplar memory accuracies were above 90% for categories for which a single exemplar had been encoded. When more exemplars per category were encoded, category memory improved, but exemplar memory declined. An exception was face memory, which remained highly accurate even after many faces had been encoded. Our study provided no evidence that visual memory in general, and face memory in particular, is impaired in children with ASD.