In this article, we begin with a summary of the evidence for perceptual narrowing for various aspects of language (e.g., vowel and consonant contrasts, tone languages, visual language, sign language) and of faces (e.g., own species, own race). We then consider possible reasons for the apparent differences in the timing of narrowing (e.g., apparently earlier for own race than for own species). Throughout we consider whether the evidence fits a model of maintenance/loss or is better characterized as enhancement/attunement to exposed categories. Finally, we consider evidence on the malleability of the timing and its implications for the role of endogenous factors versus learning in controlling when narrowing occurs. Overall, the comparison across domains revealed many similarities but also striking differences which lead to suggestions for future research.

Perceptual Narrowing During Infancy: A Comparison of Language and Faces

From faces to hands: Changing visual input in the first two years.

We offer a new solution to the unsolved problem of how infants break into word learning based on the visual statistics of everyday infant-perspective scenes. Images from head camera video captured ...

/pdf/real-world-visual-statistics-and-infants-first-learned-1uaa17ytka.pdf

Real-world visual statistics and infants' first-learned object names.

The Developing Infant Creates a Curriculum for Statistical Learning

Mature face perception has its origins in the face experiences of infants. However, little is known about the basic statistics of faces in early visual environments. We used head cameras to capture and analyze over 72,000 infant-perspective scenes from 22 infants aged 1-11 months as they engaged in daily activities. The frequency of faces in these scenes declined markedly with age: for the youngest infants, faces were present 15 minutes in every waking hour but only 5 minutes for the oldest infants. In general, the available faces were well characterized by three properties: (1) they belonged to relatively few individuals; (2) they were close and visually large; and (3) they presented views showing both eyes. These three properties most strongly characterized the face corpora of our youngest infants and constitute environmental constraints on the early development of the visual system.

The Faces in Infant-Perspective Scenes Change over the First Year of Life.

Exposure to faces is known to shape and change the face processing system; however, no study has yet documented infants' natural daily first-hand exposure to faces. One- and three-month-old infants' visual experience was recorded through head-mounted cameras. The video recordings were coded for faces to determine: (1) How often are infants exposed to faces? (2) To what type of faces are they exposed? and (3) Do frequently encountered face types reflect infants' typical pattern of perceptual narrowing? As hypothesized, infants spent a large proportion of their time (25%) exposed to faces; these faces were primarily female (70%), own-race (96%), and adult-age (81%). Infants were exposed to more individual exemplars of female, own-race, and adult-age faces than to male, other-race, and child- or older-adult-age faces. Each exposure to own-race faces was longer than to other-race faces. There were no differences in exposure duration related to the gender or age of the face. Previous research has found that the face types frequently experienced by our participants are preferred over and more successfully recognized than other face types. The patterns of face exposure revealed in the current study coincide with the known trajectory of perceptual narrowing seen later in infancy.© 2013 The Authors. Developmental Psychobiology Published by Wiley Periodicals, Inc. Dev Psychobiol 56: 249–261, 2014.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/dev.21183

I spy with my little eye: typical, daily exposure to faces documented from a first-person infant perspective.

Infants show facility for discriminating between individual faces within hours of birth. Over the first year of life, infants' face discrimination shows continued improvement with familiar face types, such as own-race faces, but not with unfamiliar face types, like other-race faces. The goal of this meta-analytic review is to provide an effect size for infants' face discrimination ability overall, with own-race faces, and with other-race faces within the first year of life, how this differs with age, and how it is influenced by task methodology. Inclusion criteria were (a) infant participants aged 0 to 12 months, (b) completing a human own- or other-race face discrimination task, (c) with discrimination being determined by infant looking. Our analysis included 30 works (165 samples, 1,926 participants participated in 2,623 tasks). The effect size for infants' face discrimination was small, 6.53% greater than chance (i.e., equal looking to the novel and familiar). There was a significant difference in discrimination by race, overall (own-race, 8.18%; other-race, 3.18%) and between ages (own-race: 0- to 4.5-month-olds, 7.32%; 5- to 7.5-month-olds, 9.17%; and 8- to 12-month-olds, 7.68%; other-race: 0- to 4.5-month-olds, 6.12%; 5- to 7.5-month-olds, 3.70%; and 8- to 12-month-olds, 2.79%). Multilevel linear (mixed-effects) models were used to predict face discrimination; infants' capacity to discriminate faces is sensitive to face characteristics including race, gender, and emotion as well as the methods used, including task timing, coding method, and visual angle. (PsycINFO Database Record

Meta-analytic review of the development of face discrimination in infancy: Face race, face gender, infant age, and methodology moderate face discrimination.

Experience has been theorized to shape how we process faces. Frequent face types are better discriminated and processed using expert-level holistic strategies while less frequent types are less well discriminated and processed using less mature featural strategies. Although experience is probably influencing the development of face processing, it is unclear what aspects of experience are most influential. The current study utilized infant-perspective head-mounted cameras to capture infants' daily lives at 1 and 3 months of age to measure the perceptual qualities of frequent and infrequent face types. We examined experience with upright (i.e., frequently experienced) and inverted (i.e., infrequently experienced) faces. A large majority (88%) of all face exposure was to upright faces. Most faces, regardless of orientation, were viewed near to the infant, alone in the field of view, and in a frontal viewpoint (i.e., an "ideal view"). Although they were less frequent than upright faces, proportionally more non-upright faces were viewed in an "ideal view". At this young age, nearly all faces, even non-upright faces, are seen in ways that facilitate processing.

Hey baby, what's “up”? One- and 3-month-olds experience faces primarily upright but non-upright faces offer the best views

Psychological and developmental research have been critiqued for the lack of diversity of research samples Because differences in culture, race, and ethnicity can influence participant behavior, limited diversity limits the generalizability of the findings These differences may also impact how participants behave in response to recruitment attempts, which suggests that recruitment itself may be leveraged to increase sample diversity The goal of the current study was to determine what factors, within a recruitment interaction, could be leveraged to increase success and diversity when recruiting families with children for developmental research Study 1 found three factors influenced success: 1) recruitment was more successful when other potential participants were also interested (ie, recruiters were busy), 2) recruiters of particular races were more successful than recruiters of other races, and 3) differences in success were related to what the recruiter said to engage the potential participant (ie, the script) The latter two factors interacted, suggesting some recruiters were using less optimal scripts To improve success rates, study 2 randomly assigned scripts to recruiters and encouraged them to recruit more vigorously during busy periods Study 2 found that two factors influenced success: 1) some scripts were more successful than others and 2) we were more successful at recruiting non-White potential participants than White participants These two interacted, with some scripts being more successful with White and other scripts being more successful with non-White families This intervention significantly increased recruitment success rate by 81% and the overall number of families recruited by 153% These findings reveal that empirically evaluating and tailoring recruitment efforts based on the most successful strategies is effective in boosting diversity through increased participation of children from non-White families

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Recruitment strategies should not be randomly selected: empirically improving recruitment success and diversity in developmental psychology research.

These are the people in your neighbourhood: Consistency and persistence in infants' exposure to caregivers', relatives', and strangers' faces across contexts.

Nicole A. Sugden

Papers

I spy with my little eye: typical, daily exposure to faces documented from a first-person infant perspective.

Meta-analytic review of the development of face discrimination in infancy: Face race, face gender, infant age, and methodology moderate face discrimination.

Hey baby, what's “up”? One- and 3-month-olds experience faces primarily upright but non-upright faces offer the best views

Recruitment strategies should not be randomly selected: empirically improving recruitment success and diversity in developmental psychology research.

These are the people in your neighbourhood: Consistency and persistence in infants' exposure to caregivers', relatives', and strangers' faces across contexts.