Newborns' recognition of changing and unchanging aspects of schematic faces

Processing Individually Distinctive Schematic-Faces Supports Proto-Arithmetical Counting in the Young Domestic Chicken

Simple Summary

Baby chicks, like infants and other animals, are unable to distinguish 3 vs. 4 identical objects. Because infants and chicks discriminate among larger sets (e.g., 4 vs. 12; 6 vs. 9), the 3 vs. 4 limitation has been considered the key-signature of the counting cognitive system that processes small numerosities. Here, we explored if the experience with different bird-like faces as objects—which naturally trigger chicks’ attention—could make the 3 vs. 4 task easier. Chicks reared with seven different faces, characterized by two “eyes” and a “beak” as features, succeeded in the 1 + 1 + 1 vs. 1 + 1 + 1 + 1 operation (Exp. 1); while birds, reared and tested with seven identical copies of a same face, failed (Exp. 2). Processing different individuals, and not experience with copies of one single individual per se, increased proto-arithmetic performance. Surprisingly, chicks, after being reared with seven identical faces, succeeded in the proto-arithmetic task when presented with seven completely novel faces (Exp. 3). On the contrary, similar experience with seven identical and featureless faces did not allow discrimination of novel faces (Exp. 4). Experience of one face probably helps to focus on the facial features which are later used to individually process new faces. In turn, individual processing enhances proto-arithmetical calculation.

Abstract

A key signature of small-number processing is the difficulty in discriminating between three and four objects, as reported in infants and animals. Five-day-old chicks overcome this limit if individually distinctive features characterize each object. In this study, we have investigated whether processing individually different face-like objects can also support discrimination between three and four objects. Chicks were reared with seven face-like stimuli and tested in the proto-arithmetic comparison 1 + 1 + 1 vs. 1 + 1 + 1 + 1. Birds reared and tested with all different faces discriminated and approached the larger group (Exp. 1), whereas new birds reared and tested with seven identical copies of one same face failed (Exp. 2). The presence at test of individually different faces allowed discrimination even when chicks were reared with copies of one face (Exp. 3). To clarify the role of the previous experience of at least one specific arrangement of facial features, in Experiment 4, featureless faces were employed during rearing. During testing, chicks were unable to discriminate between three and four individually distinct faces. Results highlight the importance of having experienced at least one “face” in prompting individual processing and proto-arithmetical calculation later during testing. We speculate that mechanisms effective at the non-symbolic level may positively affect numerical performance.

Face Processing in Early Development: A Systematic Review of Behavioral Studies and Considerations in Times of COVID-19 Pandemic

Human faces are one of the most prominent stimuli in the visual environment of young infants and convey critical information for the development of social cognition. During the COVID-19 pandemic, mask wearing has become a common practice outside the home environment. With masks covering nose and mouth regions, the facial cues available to the infant are impoverished. The impact of these changes on development is unknown but is critical to debates around mask mandates in early childhood settings. As infants grow, they increasingly interact with a broader range of familiar and unfamiliar people outside the home; in these settings, mask wearing could possibly influence social development. In order to generate hypotheses about the effects of mask wearing on infant social development, in the present work, we systematically review N = 129 studies selected based on the most recent PRISMA guidelines providing a state-of-the-art framework of behavioral studies investigating face processing in early infancy. We focused on identifying sensitive periods during which being exposed to specific facial features or to the entire face configuration has been found to be important for the development of perceptive and socio-communicative skills. For perceptive skills, infants gradually learn to analyze the eyes or the gaze direction within the context of the entire face configuration. This contributes to identity recognition as well as emotional expression discrimination. For socio-communicative skills, direct gaze and emotional facial expressions are crucial for attention engagement while eye-gaze cuing is important for joint attention. Moreover, attention to the mouth is particularly relevant for speech learning. We discuss possible implications of the exposure to masked faces for developmental needs and functions. Providing groundwork for further research, we encourage the investigation of the consequences of mask wearing for infants' perceptive and socio-communicative development, suggesting new directions within the research field.

Is human face recognition lateralized to the right hemisphere due to neural competition with left-lateralized visual word recognition? A critical review

The right hemispheric lateralization of face recognition, which is well documented and appears to be specific to the human species, remains a scientific mystery. According to a long-standing view, the evolution of language, which is typically substantiated in the left hemisphere, competes with the cortical space in that hemisphere available for visuospatial processes, including face recognition. Over the last decade, a specific hypothesis derived from this view according to which neural competition in the left ventral occipito-temporal cortex with selective representations of letter strings causes right hemispheric lateralization of face recognition, has generated considerable interest and research in the scientific community. Here, a systematic review of studies performed in various populations (infants, children, literate and illiterate adults, left-handed adults) and methodologies (behavior, lesion studies, (intra)electroencephalography, neuroimaging) offers little if any support for this reading lateralized neural competition hypothesis. Specifically, right-lateralized face-selective neural activity already emerges at a few months of age, well before reading acquisition. Moreover, consistent evidence of face recognition performance and its right hemispheric lateralization being modulated by literacy level during development or at adulthood is lacking. Given the absence of solid alternative hypotheses and the key role of neural competition in the sensory-motor cortices for selectivity of representations, learning, and plasticity, a revised language-related neural competition hypothesis for the right hemispheric lateralization of face recognition should be further explored in future research, albeit with substantial conceptual clarification and advances in methodological rigor.

Individually distinctive features facilitate numerical discrimination of sets of objects in domestic chicks

Day-old domestic chicks approach the larger of two groups of identical objects, but in a 3 vs 4 comparison, their performance is random. Here we investigated whether adding individually distinctive features to each object would facilitate such discrimination. Chicks reared with 7 objects were presented with the operation 1 + 1 + 1 vs 1 + 1 + 1 + 1. When objects were all identical, chicks performed randomly, as expected (Experiment 1). In the remaining experiments, objects differed from one another due to additional features. Chicks succeeded when those features were differently oriented segments (Experiment 2) but failed when the features were arranged to depict individually different face-like displays (Experiment 3). Discrimination was restored if the face-like stimuli were presented upside-down, disrupting global processing (Experiment 4). Our results support the claim that numerical discrimination in 3 vs 4 comparison benefits from the presence of distinctive features that enhance object individuation due to individual processing. Interestingly, when the distinctive features are arranged into upright face-like displays, the process is susceptible to global over local interference due to configural processing. This study was aimed at assessing whether individual object processing affects numerical discrimination. We hypothesise that in humans similar strategies aimed at improving performance at the non-symbolic level may have positive effects on symbolic mathematical abilities.

Subcortico-Cortical Functional Connectivity in the Fetal Brain: A Cognitive Development Blueprint

Recent evidence has shown that patterns of cortico-cortical functional synchronization are consistently traceable by the end of the third trimester of pregnancy. The involvement of subcortical structures in early functional and cognitive development has never been explicitly investigated, notwithstanding their pivotal role in different cognitive processes. We address this issue by exploring subcortico-cortical functional connectivity at rest in a group of normally developing fetuses between the 25th and 32nd weeks of gestation. Results show significant functional coupling between subcortical nuclei and cortical networks related to: (i) sensorimotor processing, (ii) decision making, and (iii) learning capabilities. This functional maturation framework unearths a Cognitive Development Blueprint, according to which grounding cognitive skills are planned to develop with higher ontogenetic priority. Specifically, our evidence suggests that a newborn already possesses the ability to: (i) perceive the world and interact with it, (ii) create salient representations for the selection of adaptive behaviors, and (iii) store, retrieve, and evaluate the outcomes of interactions, in order to gradually improve adaptation to the extrauterine environment.

Why Faces Are Not Special to Newborns

Newborns' visual preference for faces might be regarded as a proof of the existence of a specific innate bias toward this class of stimuli. However, recent research has shown that this putatively face-specific phenomenon might be explained as the result of the combined effect of nonspecific perceptual constraints that stem from the general properties of visual processing shortly after birth. General, nonspecific biases may tune the system toward certain aspects of the external environment, allowing, through experience, the emergence of increasingly specialized processes devoted to faces.

The two-process theory of face processing: modifications based on two decades of data from infants and adults

Johnson and Morton (1991. Biology and Cognitive Development: The Case of Face Recognition. Blackwell, Oxford) used Gabriel Horn's work on the filial imprinting model to inspire a two-process theory of the development of face processing in humans. In this paper we review evidence accrued over the past two decades from infants and adults, and from other primates, that informs this two-process model. While work with newborns and infants has been broadly consistent with predictions from the model, further refinements and questions have been raised. With regard to adults, we discuss more recent evidence on the extension of the model to eye contact detection, and to subcortical face processing, reviewing functional imaging and patient studies. We conclude with discussion of outstanding caveats and future directions of research in this field.

Eye-catching odors: olfaction elicits sustained gazing to faces and eyes in 4-month-old infants

This study investigated whether an odor can affect infants' attention to visually presented objects and whether it can selectively direct visual gaze at visual targets as a function of their meaning. Four-month-old infants (n = 48) were exposed to their mother's body odors while their visual exploration was recorded with an eye-movement tracking system. Two groups of infants, who were assigned to either an odor condition or a control condition, looked at a scene composed of still pictures of faces and cars. As expected, infants looked longer at the faces than at the cars but this spontaneous preference for faces was significantly enhanced in presence of the odor. As expected also, when looking at the face, the infants looked longer at the eyes than at any other facial regions, but, again, they looked at the eyes significantly longer in the presence of the odor. Thus, 4-month-old infants are sensitive to the contextual effects of odors while looking at faces. This suggests that early social attention to faces is mediated by visual as well as non-visual cues.

Human newborns match tongue protrusion of disembodied human and robotic mouths

No evidence had been provided so far of newborns’ capacity to give a matching response to 2D stimuli. We report evidence from 18 newborns who were presented with three types of stimuli on a 2D screen. The stimuli were video-recorded displays of tongue protrusion shown by: (a) a human face, (b) a human tongue from a disembodied mouth, and (c) an artificial tongue from a robotic mouth. Compared to a baseline condition, neonates increased significantly their tongue protrusion when seeing disembodied human and artificial tongue movements, but not when seeing a 2D full-face protruding tongue. This result was interpreted as revealing the exploration of top-heavy patterns of the 2D face that distracted infants’ attention from the tongue. Results also showed progressively more accurate matching (full tongue protrusion) throughout repeated exposure to each kind of stimulus. Such findings are not in line with the predictions of the innate releasing mechanism (IRM) model or of the oral exploration hypothesis. They support the active intermodal mapping (AIM) hypothesis that emphasizes not only the importance of repeated experience, as would the associative sequence learning (ASL) hypothesis, but also predicts a differential learning and progressive correction of the response adapted to each stimulus.

Statistical learning as a basis for social understanding in children

Many authors have argued that infants understand goals, intentions, and beliefs. We posit that infants' success on such tasks might instead reveal an understanding of behaviour, that infants' proficient statistical learning abilities might enable such insights, and that maternal talk scaffolds children's learning about the social world as well. We also consider which skills and insights are likely to be innate, and why it is difficult to say exactly when children understand mental states as opposed to behaviours.

Recognition of unfamiliar talking faces at birth

Sai (2005) investigated the role of speech in newborns’ recognition of their mothers’ faces. Her results revealed that, when presented with both their mother’s face and that of a stranger, newborns preferred looking at their mother only if she had previously talked to them. The present study attempted to extend these findings to any other faces. By using video films, our results revealed that unfamiliar female faces were recognized in the test phase only if they had previously talked to the baby, but not if they had been silent. These results highlight the importance of an early audiovisual perception which already seems to play an important role in face processing at birth.

Putting culture under the 'spotlight' reveals universal information use for face recognition

Background

Eye movement strategies employed by humans to identify conspecifics are not universal. Westerners predominantly fixate the eyes during face recognition, whereas Easterners more the nose region, yet recognition accuracy is comparable. However, natural fixations do not unequivocally represent information extraction. So the question of whether humans universally use identical facial information to recognize faces remains unresolved.

Methodology/Principal Findings

We monitored eye movements during face recognition of Western Caucasian (WC) and East Asian (EA) observers with a novel technique in face recognition that parametrically restricts information outside central vision. We used ‘Spotlights’ with Gaussian apertures of 2°, 5° or 8° dynamically centered on observers' fixations. Strikingly, in constrained Spotlight conditions (2° and 5°) observers of both cultures actively fixated the same facial information: the eyes and mouth. When information from both eyes and mouth was simultaneously available when fixating the nose (8°), as expected EA observers shifted their fixations towards this region.

Conclusions/Significance

Social experience and cultural factors shape the strategies used to extract information from faces, but these results suggest that external forces do not modulate information use. Human beings rely on identical facial information to recognize conspecifics, a universal law that might be dictated by the evolutionary constraints of nature and not nurture.

The "Humpty Dumpty Problem" in the Study of Early Cognitive Development: Putting the Infant Back Together Again

In this article, I propose that the big question for the field of infant cognitive development is best characterized as the "Humpty Dumpty problem": Now that we have studied cognitive abilities in isolation, how do we put the developing cognitive system (and the infant) back together again? This problem is significant because cognitive abilities do not occur in isolation. Infants remember the items they have attended to and perceived, and their emotional state will influence their perception and representation of the events they encounter. Moreover, by examining the development of the whole cognitive system, or the whole child, we gain a deeper understanding of mechanisms developmental change. Thus, the big question for the study of infant cognition is like the question confronting all the king's horses and all the king's men: How do we put the infant's cognitive system back together again?

18-Month-olds can perceive Mooney faces

The ability to detect facial information despite poor visual conditions is important for young infants. The present study investigated the developmental course of facial information detection by examining whether infants perceive Mooney faces, a well-studied type of impoverished face image. The 18-month-olds preferred upright Mooney faces to inverted ones, but 12- and 6-month-olds did not show any signs of discriminating the upright Mooney faces from inverted ones. These results indicate that 18-month-olds possess the ability to perceive Mooney faces, but definitive conclusions cannot be drawn regarding the ability to perceive Mooney faces in younger infants.

Effect of partial occlusion on newborns' face preference and recognition

Many studies have shown that newborns prefer (e.g. Goren, Sarty & Wu, 1975; Valenza, Simion, Macchi Cassia & Umiltà, 1996) and recognize (e.g. Bushnell, Say & Mullin, 1989; Pascalis & de Schonen, 1994) faces. However, it is not known whether, at birth, faces are still preferred and recognized when some of their parts are not visible because hindered by other configurations, that is when faces are partly occluded. Also, it is not known whether newborns' preference for an upright over an inverted face and newborns' face recognition are differentially affected depending on the salience of the occluded face features. Seventy-seven newborns (mean age of 43.5 hrs) were tested using the preferential looking (Experiment 1) and the habituation techniques (Experiment 2). Results demonstrated that newborns prefer and recognize occluded faces even if some portions of them are not available, at least when the hindered features are not salient. On the contrary, these abilities are affected by obscuring high salience facial features (i.e. eyes). However, while in the case of face detection, eyes occlusion completely prevented newborns' face detection, in the case of face recognition an analogous stimulus manipulation heavily impaired, but did not totally preclude, newborns' recognition performance. The data collected improve our comprehension of newborns' way of processing and encoding information to detect and recognize faces.

Newborns’ face recognition over changes in viewpoint

The study investigated the origins of the ability to recognize faces despite rotations in depth. Four experiments are reported that tested, using the habituation technique, whether 1-to-3-day-old infants are able to recognize the invariant aspects of a face over changes in viewpoint. Newborns failed to recognize facial perceptual invariances between profile and full-face poses (Experiment 1), and profile and 3/4 poses (Experiment 3). Conversely, newborns recognized the identity of a face through full-face and 3/4 poses (Experiment 2). This result cannot be explained as a consequence of newborns' inability to discriminate between the full-face and 3/4 points of view (Experiment 4). Overall, evidence was provided that newborns are able to derive a representation of an unfamiliar face that is resilient to a certain degree of rotation in depth, from full-face to 3/4 and vice versa.

Impairments in monkey and human face recognition in 2-year-old toddlers with Autism Spectrum Disorder and Developmental Delay

Face recognition impairments are well documented in older children with Autism Spectrum Disorders (ASD); however, the developmental course of the deficit is not clear. This study investigates the progressive specialization of face recognition skills in children with and without ASD. Experiment 1 examines human and monkey face recognition in 2-year-old children with ASD, matched for nonverbal mental age (NVMA) with developmentally delayed (DD) children, and typically developing children (TD), using the Visual Paired Comparison (VPC) paradigm. Results indicate that, consistent with the other-species effect, TD controls show enhanced recognition of human but not monkey faces; however, neither the ASD nor the DD group show evidence of face recognition regardless of the species. Experiment 2 examines the same question in a group of older 3- to 4-year-old developmentally disabled (ASD and DD) children as well as in typical controls. In this experiment, both human and monkey faces are recognized by all three groups. The results of Experiments 1 and 2 suggest that difficulties in face processing, as measured by the VPC paradigm, are common in toddlers with ASD as well as DD, but that these deficits tend to disappear by early preschool age. In addition, the experiments show that higher efficacy of incidental encoding and recognition of facial identity in a context of passive exposure is positively related to nonverbal cognitive skills and age, but not to overall social interaction skills or greater attention to faces exhibited in naturalistic contexts.

Qualitative differences in the exploration of upright and upside-down faces in four-month-old infants: an eye-movement study

Four-month-old infants were habituated with an upright or an upside-down face. Eye-movement recordings showed that the upright and upside-down faces were not explored the same way. Infants spent more time exploring internal features, mainly in the region of the nose and mouth, when the face was upright. They also alternated as frequently between the face's internal features (eyes vs. nose/mouth) as between external and internal features. When the face was upside down, the infants spent half of their time exploring external features, and preferentially alternated between external features and internal features. The main effect of inversion was a decrease of the looking time to the nose/mouth region and of the number of shifts between the eye region and the nose/mouth region.

Newborns' face recognition: role of inner and outer facial features

Existing data indicate that newborns are able to recognize individual faces, but little is known about what perceptual cues drive this ability. The current study showed that either the inner or outer features of the face can act as sufficient cues for newborns' face recognition (Experiment 1), but the outer part of the face enjoys an advantage over the inner part (Experiment 2). Inversion of the face stimuli disrupted recognition when only the inner portion of the face was shown, but not when the whole face was fully visible or only the outer features were presented (Experiment 3). The results enhance our picture of what information newborns actually process and encode when they discriminate, learn, and recognize faces.

Structural Equation Modeling of Paired-Comparison and Ranking Data

L. L. Thurstone's (1927) model provides a powerful framework for modeling individual differences in choice behavior. An overview of Thurstonian models for comparative data is provided, including the classical Case V and Case III models as well as more general choice models with unrestricted and factor-analytic covariance structures. A flow chart summarizes the model selection process. The authors show how to embed these models within a more familiar structural equation modeling (SEM) framework. The different special cases of Thurstone's model can be estimated with a popular SEM statistical package, including factor analysis models for paired comparisons and rankings. Only minor modifications are needed to accommodate both types of data. As a result, complex models for comparative judgments can be both estimated and tested efficiently.