Size constancy at birth: newborn infants' responses to retinal and real size

Monocular gap stereopsis in infants

In monocular gap stereopsis, one eye perceives a complete rectangular surface while the other eye perceives two small adjacent rectangular surfaces separated by a narrow vertical gap. Our visual system interprets the difference caused by the unmatched monocular images as a depth difference between two small rectangles. In a spontaneous visual preference study, it was asked whether participants aged 4 months responded to the depth effect generated by a monocular gap. Two experimental conditions were conducted. In one (large outer edge disparity condition), the monocular depth effect was twice as strong as in the other one (small outer edge disparity condition), according to the experimental research with adult participants conducted by Pianta and Gillam (2003, Vision Research, Vol. 43, pp. 1937-1950). In both conditions, it was tested whether the stimulus bearing monocular gap stereopsis was preferred over a comparison stimulus without depth. According to the results, the participants preferred looking at the stimulus with monocular stereopsis in the large outer edge disparity condition over doing so in the small outer edge disparity condition. Moreover, the difference between experimental conditions was significant; that is, the infants displayed a stronger spontaneous preference in the condition with the large outer edge disparity than in the condition with the small outer edge disparity. These findings provide evidence to suggest that infants aged 4 months are able to respond to monocular vertical gap information.

A cross-cultural investigation of people's intuitive beliefs about the origins of cognition

Nature vs. nurture is an enduring theme of studies of the mind. Past studies on American children and adults have revealed a preference for thinking that even fundamental cognitive abilities documented in human infants and non-human species are late-emerging and reliant on learning and nurture. However, little is known about the generalizability of this "intuitive empiricist" belief and what factors may help explain it. Adult participants (N = 600) reported their beliefs about the emergence of several fundamental cognitive abilities demonstrated by preverbal infants. Studies 1A-1C showed that adults from both Japan and the US similarly estimated an older age of onset for cognitive abilities in human children as compared to the findings of cognitive science and consistently attributed acquisition of these abilities to learning rather than innateness in humans, and they made these learning attributions more so for humans than for non-human species. Study 2 showed that participants' beliefs about biological evolution versus creationism were related to their age onset estimates for fundamental cognitive abilities, and their beliefs about the malleability of intelligence were related to participants' explanations of the origin of fundamental cognitive abilities. These findings suggest generalizable preferences for nurture over nature across both Eastern and Western cultures (Japan and the United States), which may be related to people's beliefs about human origins and the power of learning.

Abstract representations of small sets in newborns

From the very first days of life, newborns are not tied to represent narrow, modality- and object-specific aspects of their environment. Rather, they sometimes react to abstract properties shared by stimuli of very different nature, such as approximate numerosity or magnitude. As of now, however, there is no evidence that newborns possess abstract representations that apply to small sets: in particular, while newborns can match large approximate numerosities across senses, this ability does not extend to small numerosities. In two experiments, we presented newborn infants (N = 64, age 17 to 98 h) with patterned sets AB or ABB simultaneously in the auditory and visual modalities. Auditory patterns were presented as periodic sequences of sounds (AB: triangle-drum-triangle-drum-triangle-drum …; ABB: triangle-drum-drum-triangle-drum-drum-triangle-drum-drum …), and visual patterns as arrays of 2 or 3 shapes (AB: circle-diamond; ABB: circle-diamond-diamond). In both experiments, we found that participants reacted and looked longer when the patterns matched across the auditory and visual modalities – provided that the first stimulus they received was congruent. These findings uncover the existence of yet another type of abstract representations at birth, applying to small sets. As such, they bolster the hypothesis that newborns are endowed with the capacity to represent their environment in broad strokes, in terms of its most abstract properties. This capacity for abstraction could later serve as a scaffold for infants to learn about the particular entities surrounding them.

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Newborns were presented with auditory and visual patterns (AB vs. ABB).

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Participants reacted when the patterns presented were congruent across modalities.

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Newborns possess abstract representations applying to small sets.

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These representations may encode numerosity and/or repetitions.

Visual foundations of Euclidean geometry

Geometry defines entities that can be physically realized in space, and our knowledge of abstract geometry may therefore stem from our representations of the physical world. Here, we focus on Euclidean geometry, the geometry historically regarded as "natural". We examine whether humans possess representations describing visual forms in the same way as Euclidean geometry - i.e., in terms of their shape and size. One hundred and twelve participants from the U.S. (age 3-34 years), and 25 participants from the Amazon (age 5-67 years) were asked to locate geometric deviants in panels of 6 forms of variable orientation. Participants of all ages and from both cultures detected deviant forms defined in terms of shape or size, while only U.S. adults drew distinctions between mirror images (i.e. forms differing in "sense"). Moreover, irrelevant variations of sense did not disrupt the detection of a shape or size deviant, while irrelevant variations of shape or size did. At all ages and in both cultures, participants thus retained the same properties as Euclidean geometry in their analysis of visual forms, even in the absence of formal instruction in geometry. These findings show that representations of planar visual forms provide core intuitions on which humans' knowledge in Euclidean geometry could possibly be grounded.

Size Constancy Mechanisms: Empirical Evidence from Touch

Several studies have shown the presence of large anisotropies for tactile distance perception across several parts of the body. The tactile distance between two touches on the dorsum of the hand is perceived as larger when they are oriented mediolaterally (across the hand) than proximodistally (along the hand). This effect can be partially explained by the characteristics of primary somatosensory cortex representations. However, this phenomenon is significantly attenuated relative to differences in acuity and cortical magnification, suggesting a process of tactile size constancy. It is unknown whether the same kind of compensation also takes place when estimating the size of a continuous object. Here, we investigate whether the tactile anisotropy that typically emerges when participants have to estimate the distance between two touches is also present when a continuous object touches the skin and participants have to estimate its size. In separate blocks, participants judged which of two tactile distances or objects on the dorsum of their hand felt larger. One stimulation (first or second) was aligned with the proximodistal axis (along the hand) and the other with the mediolateral axis (across the hand). Results showed a clear anisotropy for distances between two distinct points, with across distances consistently perceived as larger than along distances, as in previous studies. Critically, however, this bias was significantly reduced or absent for judgments of the length of continuous objects. These results suggest that a tactile size constancy process is more effective when the tactile size of an object has to be approximated compared to when the distance between two touches has to be determined. The possible mechanism subserving these results is described and discussed. We suggest that a lateral inhibition mechanism, when an object touches the skin, provides information through the distribution of the inhibitory subfields of the RF about the shape of the tactile RF itself. Such a process allows an effective tactile size compensatory mechanism where a good match between the physical and perceptual dimensions of the object is achieved.

Can People Infer Distance in a 2D Scene Using the Visual Size and Position of an Object?

Depth information is limited in a 2D scene and for people to perceive the distance of an object, they need to rely on pictorial cues such as perspective, size constancy and elevation in the scene. In this study, we tested whether people could use an object’s size and its position in a 2D image to determine its distance. In a series of online experiments, participants viewed a target representing their smartphone rendered within a 2D scene. They either positioned it in the scene at the distance they thought was correct based on its size or adjusted the target to the correct size based on its position in the scene. In all experiments, the adjusted target size and positions were not consistent with their initially presented positions and sizes and were made larger and moved further away on average. Familiar objects influenced adjusted position from size but not adjusted size from position. These results suggest that in a 2D scene, (1) people cannot use an object’s visual size and position relative to the horizon to infer distance reliably and (2) familiar objects in the scene affect perceived size and distance differently. The differences found demonstrate that size and distance perception processes may be independent.

Developmental Trajectories of Size Constancy as Implicitly Examined by Simple Reaction Times

It is still unclear whether size constancy is an innate ability or whether it develops with age. As many developmental studies are limited to the child's comprehension of the task instructions, here, an implicit measure of perceived size, namely, simple manual reaction time (RT), was opted for based on the assumption that perceptually bigger objects generate faster detection times. We examined size constancy in children (from 5 to 14 years of age) and adults using a simple RT approach. Participants were presented with pictures of tennis balls on a screen that was physically moved to two viewing distances. Visual stimuli were adjusted in physical size in order to subtend the same visual angle across distances, determining two conditions: a small-near tennis ball vs. a big-far tennis ball. Thanks to size constancy, the two tennis balls were perceived as different even though they were of equal size on the retina. Stimuli were also matched in terms of luminance. Participants were asked to react as fast as possible to the onset of the stimuli. The results show that the RTs reflected the perceived rather than the retinal size of the stimuli across the different age groups, such that participants responded faster to stimuli that were perceived as bigger than those perceived as smaller. Hence, these findings are consistent with the idea that size constancy is already present in early childhood, at least from the age of five, and does not require extensive visual learning.

A review on various explanations of Ponzo-like illusions

This article reviews theoretical and empirical arguments for and against various theories that explain the classic Ponzo illusion and its variants from two different viewpoints concerning the role of perceived depth in size distortions. The first viewpoint argues that all Ponzo-like illusions are driven by perceived depth. The second viewpoint argues that the classic Ponzo illusion is unrelated to depth perception. This review will give special focus to the first viewpoint and consists of three sections. In the first section, the role of the number of pictorial depth cues and previous experience in the strength of all Ponzo-like illusions are discussed. In the second section, we contrast the first viewpoint against the theories that explain the classic Ponzo illusion with mechanisms that are unrelated to depth perception. In the last section, we propose a Bayesian-motivated reconceptualization of Richard Gregory's misapplied size constancy theory that explains Ponzo-variant illusions in terms of prior information and prediction errors. The new account explains why some studies have provided inconsistent evidence for misapplied size constancy theory.

Does Vergence Affect Perceived Size?

Since Kepler (1604) and Descartes (1637), it has been suggested that 'vergence' (the angular rotation of the eyes) plays a key role in size constancy. However, this has never been tested divorced from confounding cues such as changes in the retinal image. In our experiment, participants viewed a target which grew or shrank in size over 5 s. At the same time, the fixation distance specified by vergence was reduced from 50 to 25 cm. The question was whether this change in vergence affected the participants' judgements of whether the target grew or shrank in size? We found no evidence of any effect, and therefore no evidence that eye movements affect perceived size. If this is correct, then our finding has three implications. First, perceived size is much more reliant on cognitive influences than previously thought. This is consistent with the argument that visual scale is purely cognitive in nature (Linton, 2017; 2018). Second, it leads us to question whether the vergence modulation of V1 contributes to size constancy. Third, given the interaction between vergence, proprioception, and the retinal image in the Taylor illusion, it leads us to ask whether this cognitive approach could also be applied to multisensory integration.

Perceptual constancy with a novel sensory skill

Making sense of the world requires perceptual constancy—the stable perception of an object across changes in one’s sensation of it. To investigate whether constancy is intrinsic to perception, we tested whether humans can learn a form of constancy that is unique to a novel sensory skill (here, the perception of objects through click-based echolocation). Participants judged whether two echoes were different either because: (a) the clicks were different, or (b) the objects were different. For differences carried through spectral changes (but not level changes), blind expert echolocators spontaneously showed a high constancy ability (mean d′ = 1.91) compared to sighted and blind people new to echolocation (mean d′ = 0.69). Crucially, sighted controls improved rapidly in this ability through training, suggesting that constancy emerges in a domain with which the perceiver has no prior experience. This provides strong evidence that constancy is intrinsic to human perception.

This study shows that people who learn a new skill to sense their environment - here: listening to sound echoes - can correctly represent the physical properties of objects. This result has implications for effectively rehabilitating people with sensory loss.

Themes of advanced information processing in the primate brain

Here is a review of several empirical examples of information processing that occur in the primate cerebral cortex. These include visual processing, object identification and perception, information encoding, and memory. Also, there is a discussion of the higher scale neural organization, mainly theoretical, which suggests hypotheses on how the brain internally represents objects. Altogether they support the general attributes of the mechanisms of brain computation, such as efficiency, resiliency, data compression, and a modularization of neural function and their pathways. Moreover, the specific neural encoding schemes are expectedly stochastic, abstract and not easily decoded by theoretical or empirical approaches.

Learning to see the Ebbinghaus illusion in the periphery reveals a top-down stabilization of size perception across the visual field

Our conscious visual perception relies on predictive signals, notably in the periphery where sensory uncertainty is high. We investigated how such signals could support perceptual stability of objects' size across the visual field. When attended carefully, the same object appears slightly smaller in the periphery compared to the fovea. Could this perceptual difference be encoded as a strong prior to predict the peripheral perceived size relative to the fovea? Recent studies emphasized the role of foveal information in defining peripheral size percepts. However, they could not disentangle bottom-up from top-down mechanisms. Here, we revealed a pure top-down contribution to the perceptual size difference between periphery and fovea. First, we discovered a novel Ebbinghaus illusion effect, inducing a typical reduction of foveal perceived size, but a reversed increase effect in the periphery. The resulting illusory size percept was similar at both locations, deviating from the classic perceptual difference. Then through an updating process of successive peripheral-foveal viewing, the unusual peripheral perceived size decreased. The classic perceptual eccentricity difference was restored and the peripheral illusion effect changed into a fovea-like reduction. Therefore, we report the existence of a prior that actively shapes peripheral size perception and stabilizes it relative to the fovea.

Do infants show knowledge of the familiar size of everyday objects?

The current study aimed to examine the age at which infants exhibit knowledge of the familiar size of common everyday objects. A total of 65 7- and 12-month-old infants were presented with familiar-sized and novel-sized (i.e., larger or smaller than the familiar size) common everyday objects (i.e., pacifiers and sippy cups), which were placed out of their reach. Both 7- and 12-month-olds' first looks were more frequently directed toward physically larger objects irrespective of whether they were familiar- or novel-sized objects. This finding indicates that initial visual orientation is contingent on the magnitude of the absolute physical size of an object. However, when the entire duration of presentation of the objects (i.e., 10 s) was examined, 12-month-olds' mean looking durations were found to be longer for novel-sized objects than for familiar-sized objects. Thus, although infants in both age groups were able to discern the physical sizes of objects, only 12-month-olds could successfully discriminate between the familiar and novel sizes of everyday objects. Notably, 12-month-olds demonstrated knowledge of familiar size even though the test objects were out of their reach and, consequently, unamenable to manual exploration.

Is Empiricism Innate? Preference for Nurture Over Nature in People's Beliefs About the Origins of Human Knowledge

The origins of human knowledge are an enduring puzzle: what parts of what we know require learning, and what depends on intrinsic structure? Although the nature-nurture debate has been a central question for millennia and has inspired much contemporary research in psychology and neuroscience, it remains unknown whether people share intuitive, prescientific theories about the answer. Here we report that people (N = 1,188) explain fundamental perceptual and cognitive abilities by appeal to learning and instruction, rather than genes or innateness, even for abilities documented in the first days of life. U.S. adults, adults from a culture with a belief in reincarnation, children, and professional scientists-including psychologists and neuroscientists, all believed these basic abilities emerge significantly later than they actually do, and ascribed them to nurture over nature. These findings implicate a widespread intuitive empiricist theory about the human mind, present from early in life.

The influence of size in weight illusions is unique relative to other object features

Research into weight illusions has provided valuable insight into the functioning of the human perceptual system. Associations between the weight of an object and its other features, such as its size, material, density, conceptual information, or identity, influence our expectations and perceptions of weight. Earlier accounts of weight illusions underscored the importance of previous interactions with objects in the formation of these associations. In this review, we propose a theory that the influence of size on weight perception could be driven by innate and phylogenetically older mechanisms, and that it is therefore more deep-seated than the effects of other features that influence our perception of an object's weight. To do so, we first consider the different associations that exist between the weight of an object and its other features and discuss how different object features influence weight perception in different weight illusions. After this, we consider the cognitive, neurological, and developmental evidence, highlighting the uniqueness of size-weight associations and how they might be reinforced rather than driven by experience alone. In the process, we propose a novel neuroanatomical account of how size might influence weight perception differently than other object features do.

How Perception and Action Fosters Exploration and Selection in Infant Skill Acquisition

In this chapter, we discuss how perception and action are intimately linked to the processes of exploration and selection. Exploration, which we define as trying several variations of the behavior, and selection, which involves attempting to reproduce the behaviors that work, are essential for learning about the environment, discovering the properties of objects, and for acquiring skills in relation to goals. Exploration and selection happen in the moment and over time as behaviors are repeated, hence leading to their fine-tuning to the goal. We illustrate this time-dependent developmental process using several examples from infants reaching for objects, to discovering object properties, to learning about the functionality of tool use, and even to word learning. As we present those examples, we introduce a more detailed perception-action loop to illustrate those moment-to-moment behaviors and show how they contribute to the acquisition of perceptual, motor, and cognitive skills in infancy.

The Development of Object Fitting: The Dynamics of Spatial Coordination

Fitting objects into apertures is an adaptive skill that is incorporated into the design of many tools. We match or align shapes with openings when we insert keys into locks, when we put lids atop containers, or when we align a screwdriver with the groove of a screw. Traditionally, the development of object fitting has focused on children's abilities to successfully complete shape sorter tasks (e.g., square peg through square hole). By measuring children's success in these tasks, investigators have determined that there is substantial development during the second year, but little research has addressed the processes children employ to solve object fitting challenges during this time period. Here, we provide a process based account of object fitting, which emphasizes how children coordinate information about spatial structure with action. We suggest that a process-based approach can illuminate the real-time dynamics of perceiving, acting, and thinking.

Effect of the retinal size of a peripheral cue on attentional orienting in two- and three-dimensional worlds

It has been documented that due to limited attentional resources, the size of the attentional focus is inversely correlated with processing efficiency. Moreover, by adopting a variety of two-dimensional size illusions induced by pictorial depth cues (e.g., the Ponzo illusion), previous studies have revealed that the perceived, rather than the retinal, size of an object determines its detection. It remains unclear, however, whether and how the retinal versus perceived size of a cue influences the process of attentional orienting to subsequent targets, and whether the corresponding influencing processes differ between two-dimensional (2-D) and three-dimensional (3-D) space. In the present study, we incorporated the dot probe paradigm with either a 2-D Ponzo illusion, induced by pictorial depth cues, or a virtual 3-D world in which the Ponzo illusion turned into visual reality. By varying the retinal size of the cue while keeping its perceived size constant (Exp. 1), we found that a cue with smaller retinal size significantly facilitated attentional orienting as compared to a cue with larger retinal size, and that the effects were comparable between 2-D and 3-D displays. Furthermore, when the pictorial background was removed and the cue display was positioned in either the farther or the closer depth plane (Exp. 2), or when both the depth and the background were removed (Exp. 3), the retinal size, rather than the depth, of the cue still affected attentional orienting. Taken together, our results suggest that the retinal size of a cue plays the crucial role in the visuospatial orienting of attention in both 2-D and 3-D.

Child-Adult Differences in Using Dual-Task Paradigms to Measure Listening Effort

PURPOSE

The purpose of the project was to investigate the effects modifying the secondary task in a dual-task paradigm to measure objective listening effort. To be specific, the complexity and depth of processing were increased relative to a simple secondary task.

METHOD

Three dual-task paradigms were developed for school-age children. The primary task was word recognition. The secondary task was a physical response to a visual probe (simple task), a physical response to a complex probe (increased complexity), or word categorization (increased depth of processing). Sixteen adults (22-32 years, M = 25.4) and 22 children (9-17 years, M = 13.2) were tested using the 3 paradigms in quiet and noise.

RESULTS

For both groups, manipulations of the secondary task did not affect word recognition performance. For adults, increasing depth of processing increased the calculated effect of noise; however, for children, results with the deep secondary task were the least stable.

CONCLUSIONS

Manipulations of the secondary task differentially affected adults and children. Consistent with previous findings, increased depth of processing enhanced paradigm sensitivity for adults. However, younger participants were more likely to demonstrate the expected effects of noise on listening effort using a secondary task that did not require deep processing.

The Interaction Between Vision and Eye Movements

The existence of a central fovea, the small retinal region with high analytical performance, is arguably the most prominent design feature of the primate visual system. This centralization comes along with the corresponding capability to move the eyes to reposition the fovea continuously. Past research on visual perception was mainly concerned with foveal vision while the observers kept their eyes stationary. Research on the role of eye movements in visual perception emphasized their negative aspects, for example, the active suppression of vision before and during the execution of saccades. But is the only benefit of our precise eye movement system to provide high acuity of the small foveal region, at the cost of retinal blur during their execution? In this review, I will compare human visual perception with and without saccadic and smooth pursuit eye movements to emphasize different aspects and functions of eye movements. I will show that the interaction between eye movements and visual perception is optimized for the active sampling of information across the visual field and for the calibration of different parts of the visual field. The movements of our eyes and visual information uptake are intricately intertwined. The two processes interact to enable an optimal perception of the world, one that we cannot fully grasp by doing experiments where observers are fixating a small spot on a display.

Face perception and processing in early infancy: inborn predispositions and developmental changes

From birth it is critical for our survival to identify social agents and conspecifics. Among others stimuli, faces provide the required information. The present paper will review the mechanisms subserving face detection and face recognition, respectively, over development. In addition, the emergence of the functional and neural specialization for face processing as an experience-dependent process will be documented. Overall, the present work highlights the importance of both inborn predispositions and the exposure to certain experiences, shortly after birth, to drive the system to become functionally specialized to process faces in the first months of life.

Empathy ≠ sharing: Perspectives from phenomenology and developmental psychology

We argue that important insights regarding the topic of sharing can be gathered from phenomenology and developmental psychology; insights that in part challenge widespread ideas about what sharing is and where it can be found. To be more specific, we first exemplify how the notion of sharing is being employed in recent discussions of empathy, and then argue that this use of the notion tends to be seriously confused. It typically conflates similarity and sharing and, more generally speaking, fails to recognize that sharing proper involves reciprocity. As part of this critical analysis, we draw on sophisticated analyses of the distinction between empathy and emotional sharing that can be found in early phenomenology. Next, we turn to developmental psychology. Sharing is not simply one thing, but a complex and many-layered phenomenon. By tracing its early developmental trajectory from infancy and beyond, we show how careful psychological observations can help us develop a more sophisticated understanding of sharing than the one currently employed in many discussions in the realm of neuroscience. In our conclusion, we return to the issue of empathy and argue that although empathy does not involve or entail sharing, empathy understood as a basic sensitivity to and understanding of others (rather than as a special prosocial concern for others) might be a precondition for sharing.

Infant Perception of Incongruent Shapes in Cast Shadows

A cast shadow occurs when an object blocks the light from an illumination and projects a dark region onto a surface. Previous studies have reported that adults are slower to identify an object when the object has an incongruent cast shadow than when it has a congruent cast shadow (Castiello, 2001). Here, we used the familiarization-novelty preference procedure to examine whether 5- to 8-month-old infants could detect the relationship between object shapes and cast shadows. In Experiment 1, we examined the infants' ability to detect incongruency between objects and cast shadows. Results showed that 7- to 8-month olds could detect incongruence between the object shapes and the cast shadows, whereas 5- to 6-month olds did not. Yet, our control experiment showed that infants could not detect this incongruence from stimuli in which a white outline had been added to the original cast shadow to decrease the possibility of it being perceived as a cast shadow (Experiment 2). The results of these experiments demonstrate that 7- to 8-month olds responded to the congruence of cast shadows and to consistent contrast polarity between the cast shadow and its background.

The Role of Visual Experience in Changing the Size of Objects in Imagery Processing

Introduction

This paper investigates the question of whether or not subjects who are congenitally blind experience greater difficulties mentally in resizing images of objects than those who have low vision or are adventitiously blind.

Methods

Two experiments were conducted: one in which subjects were asked to mentally enlarge objects they previously explored manually, and one in which subjects were tested for the ability to demonstrate the change in the size of an object imagined to be moving away. Three groups of high school students with visual impairments took part in the experiment: congenitally blind, “late blind,” and those with low vision.

Results

When showing the linear size of an object enlarged in their imagination, congenitally blind participants overestimated its size more frequently than those who were late blind. The degree of mental reduction of the size of an object imagined to be moving away was comparable for all groups.

Discussion

The results suggest that the difficulties experienced by congenitally blind participants with the mental resizing of objects may be related to problems with performing mental scaling transformations. In the low vision group, the etiology of the subjects’ visual impairment was not taken into consideration. The group turned out to be heterogeneous with respect to imagery processes.

Implications for practitioners

When using models for explaining new concepts, it is important to ensure that congenitally blind learners understand the change of scale.

Infants' ability to respond to depth from the retinal size of human faces: comparing monocular and binocular preferential-looking

To examine sensitivity to pictorial depth cues in young infants (4 and 5 months-of-age), we compared monocular and binocular preferential looking to a display on which two faces were equidistantly presented and one was larger than the other, depicting depth from the size of human faces. Because human faces vary little in size, the correlation between retinal size and distance can provide depth information. As a result, adults perceive a larger face as closer than a smaller one. Although binocular information for depth provided information that the faces in our display were equidistant, under monocular viewing, no such information was provided. Rather, the size of the faces indicated that one was closer than the other. Infants are known to look longer at apparently closer objects. Therefore, we hypothesized that infants would look longer at a larger face in the monocular than in the binocular condition if they perceived depth from the size of human faces. Because the displays were identical in the two conditions, any difference in looking-behavior between monocular and binocular viewing indicated sensitivity to depth information. Results showed that 5-month-old infants preferred the larger, apparently closer, face in the monocular condition compared to the binocular condition when static displays were presented. In addition, when presented with a dynamic display, 4-month-old infants showed a stronger 'closer' preference in the monocular condition compared to the binocular condition. This was not the case when the faces were inverted. These results suggest that even 4-month-old infants respond to depth information from a depth cue that may require learning, the size of faces.

Size precedes view: developmental emergence of invariant object representations in lateral occipital complex

Although object perception involves encoding a wide variety of object properties (e.g., size, color, viewpoint), some properties are irrelevant for identifying the object. The key to successful object recognition is having an internal representation of the object identity that is insensitive to these properties while accurately representing important diagnostic features. Behavioral evidence indicates that the formation of these kinds of invariant object representations takes many years to develop. However, little research has investigated the developmental emergence of invariant object representations in the ventral visual processing stream, particularly in the lateral occipital complex (LOC) that is implicated in object processing in adults. Here, we used an fMR adaptation paradigm to evaluate age-related changes in the neural representation of objects within LOC across variations in size and viewpoint from childhood through early adulthood. We found a dissociation between the neural encoding of object size and object viewpoint within LOC: by age of 5-10 years, area LOC demonstrates adaptation across changes in size, but not viewpoint, suggesting that LOC responses are invariant to size variations, but that adaptation across changes in view is observed in LOC much later in development. Furthermore, activation in LOC was correlated with behavioral indicators of view invariance across the entire sample, such that greater adaptation was correlated with better recognition of objects across changes in viewpoint. We did not observe similar developmental differences within early visual cortex. These results indicate that LOC acquires the capacity to compute invariance specific to different sources of information at different time points over the course of development.

Staring us in the face? An embodied theory of innate face preference

Human expertise in face perception grows over development, but even within minutes of birth, infants exhibit an extraordinary sensitivity to face-like stimuli. The dominant theory accounts for innate face detection by proposing that the neonate brain contains an innate face detection device, dubbed 'Conspec'. Newborn face preference has been promoted as some of the strongest evidence for innate knowledge, and forms a canonical stage for the modern form of the nature-nurture debate in psychology. Interpretation of newborn face preference results has concentrated on monocular stimulus properties, with little mention or focused investigation of potential binocular involvement. However, the question of whether and how newborns integrate the binocular visual streams bears directly on the generation of observable visual preferences. In this theoretical paper, we employ a synthetic approach utilizing robotic and computational models to draw together the threads of binocular integration and face preference in newborns, and demonstrate cases where the former may explain the latter. We suggest that a system-level view considering the binocular embodiment of newborn vision may offer a mutually satisfying resolution to some long-running arguments in the polarizing debate surrounding the existence and causal structure of newborns' 'innate knowledge' of faces.

Bilateral gain control; an "innate predisposition" for all sorts of things

Empirical studies have revealed remarkable perceptual organization in neonates. Newborn behavioral distinctions have often been interpreted as implying functionally specific modular adaptations, and are widely cited as evidence supporting the nativist agenda. In this theoretical paper, we approach newborn perception and attention from an embodied, developmental perspective. At the mechanistic level, we argue that a generative mechanism based on mutual gain control between bilaterally corresponding points may underly a number of functionally defined “innate predispositions” related to spatial-configural perception. At the computational level, bilateral gain control implements beamforming, which enables spatial-configural tuning at the front end sampling stage. At the psychophysical level, we predict that selective attention in newborns will favor contrast energy which projects to bilaterally corresponding points on the neonate subject's sensor array. The current work extends and generalizes previous work to formalize the bilateral correlation model of newborn attention at a high level, and demonstrate in minimal agent-based simulations how bilateral gain control can enable a simple, robust and “social” attentional bias.

Why do only some hyperopes become strabismic?

Children with hyperopia greater than +3.5 diopters (D) are at increased risk for developing refractive esotropia. However, only approximately 20% of these hyperopes develop strabismus. This review provides a systematic theoretical analysis of the accommodation and vergence oculomotor systems with a view to understanding factors that could either protect a hyperopic individual or precipitate a strabismus. The goal is to consider factors that may predict refractive esotropia in an individual and therefore help identify the subset of hyperopes who are at the highest risk for this strabismus, warranting the most consideration in a preventive effort.

Visual size perception and haptic calibration during development

It is still unclear how the visual system perceives accurately the size of objects at different distances. One suggestion, dating back to Berkeley's famous essay, is that vision is calibrated by touch. If so, we may expect different mechanisms involved for near, reachable distances and far, unreachable distances. To study how the haptic system calibrates vision we measured size constancy in children (from 6 to 16 years of age) and adults, at various distances. At all ages, accuracy of the visual size perception changes with distance, and is almost veridical inside the haptic workspace, in agreement with the idea that the haptic system acts to calibrate visual size perception. Outside this space, systematic errors occurred, which varied with age. Adults tended to overestimate visual size of distant objects (over-compensation for distance), while children younger than 14 underestimated their size (under-compensation). At 16 years of age there seemed to be a transition point, with veridical perception of distant objects. When young subjects were allowed to touch the object inside the haptic workspace, the visual biases disappeared, while older subjects showed multisensory integration. All results are consistent with the idea that the haptic system can be used to calibrate visual size perception during development, more effectively within than outside the haptic workspace, and that the calibration mechanisms are different in children than in adults.

What do We Know about Neonatal Cognition?

Research on neonatal cognition has developed very recently in comparison with the long history of research on child behavior. The last sixty years of research have provided a great amount of evidence for infants' numerous cognitive abilities. However, only little of this research concerns newborn infants. What do we know about neonatal cognition? Using a variety of paradigms, researchers became able to probe for what newborns know. Amongst these results, we can distinguish several levels of cognitive abilities. First, at the perceptual or sensory level, newborns are able to process information coming from the social world and the physical objects through all their senses. They are able to discriminate between object shapes and between faces; that is, they are able to detect invariants, remember and recognize them. Second, newborns are able to abstract information, to compare different inputs and to match them across different sensory modalities. We will argue that these two levels can be considered high-level cognitive abilities: they constitute the foundations of human cognition. Furthermore, while some perceptual competencies can stem from the fetal period, many of these perceptual and cognitive abilities cannot be a consequence of the environment surrounding the newborn before birth.

Size matters: how age and reaching experiences shape infants' preferences for different sized objects

Looking and reaching preferences for different-sized objects were examined in 4-5- and 5-6-month-old infants. Infants were presented with pairs of different sized cylinders and preferences were analyzed by age and reaching status. Outcome variables included looking and touching time for each object, first look, and first touch. Significant three-way interactions with age and reaching status were found for both infants' looking and touching duration. Four-5- and 5-6-month-olds with less reaching experience spent more time visually and manually exploring larger objects. In contrast, 5-6-month-olds with more reaching experience spent more time looking at and touching smaller objects, despite a first look and first touch preference for the largest object. Initially, looking and reaching preferences seem to be driven by mechanisms responding to general visual salience independent of an object's potential for manual action. Once reaching skills emerge, infants begin to use visual information to selectively choose smaller, more graspable objects as exploration targets.

Infants' responsiveness to lightness changes on a dynamic three-dimensional surface

In a looking-time study, 24 infants 6 months of age were presented with continuously folding and unfolding patterns of stripes. The luminances in the dynamic lightness constancy pattern were changed in such way that adults attribute them to changes of the various regions' orientation relative to the light source (lightness constancy display). The "reversed" lightness constancy stimulus consisted of a continuously folding and unfolding pattern, in which the luminance changes were not consistent with a striped surface illuminated from one side. The only difference between the animations was the relationship between the change in surface orientation and the change of luminances. The infants looked significantly longer at the reversed lightness constancy animation than at the lightness constancy display. This finding suggests that the infants detected the violation of the lightness constancy rules in the reversed lightness constancy stimulus. The infants were also presented with control animations to rule out the possibility that looking preferences were based on low-level properties of the display.

Infants and toddlers show enlarged visual sensitivity to nonaccidental compared with metric shape changes

Some shape changes are more important for object perception than others. We used a habituation paradigm to measure visual sensitivity to a nonaccidental shape change—that is, the transformation of a trapezium into a triangle and vice versa—and a metric shape change—that is, changing the aspect ratio of the shapes. Our data show that an enhanced perceptual sensitivity to nonaccidental changes is already present in infancy and remains stable into toddlerhood. We have thus established an example of how early visual perception deviates from the null hypothesis of representing similarity as a function of physical overlap between shapes, and does so in agreement with more cognitive, categorical demands.