Infants' ability to use luminance information to individuate objects

Recent research indicates that infants first use form and then surface features as the basis for individuating objects. However, very little is known about the underlying basis for infants' differential sensitivity to form than surface features. The present research assessed infants' sensitivity to luminance differences. Like other surface properties, luminance information typically reveals little about an object. Unlike other surface properties (e.g. pattern, color), the visual system can detect luminance differences at birth. The outcome of two experiments indicated that 11.5-month-olds, but not 7.5-month-olds, used luminance differences to individuate objects. These results suggest that it is not the age at which infants can detect a feature, but the nature of the information carried by the feature, that determines infants' capacity to individuate objects.     

Infants' representations of three-dimensional occluded objects

Infants' ability to represent objects has received significant attention from the developmental research community. With the advent of eye-tracking technology, detailed analysis of infants' looking patterns during object occlusion have revealed much about the nature of infants' representations. The current study continues this research by analyzing infants' looking patterns in a novel manner and by comparing infants' looking at a simple display in which a single three-dimensional (3D) object moves along a continuous trajectory to a more complex display in which two 3D objects undergo trajectories that are interrupted behind an occluder. Six-month-old infants saw an occlusion sequence in which a ball moved along a linear path, disappeared behind a rectangular screen, and then a ball (ball-ball event) or a box (ball-box event) emerged at the other edge. An eye-tracking system recorded infants' eye-movements during the event sequence. Results from examination of infants' attention to the occluder indicate that during the occlusion interval infants looked longer to the side of the occluder behind which the moving occluded object was located, shifting gaze from one side of the occluder to the other as the object(s) moved behind the screen. Furthermore, when events included two objects, infants attended to the spatiotemporal coordinates of the objects longer than when a single object was involved. These results provide clear evidence that infants' visual tracking is different in response to a one-object display than to a two-object display. Furthermore, this finding suggests that infants may require more focused attention to the hidden position of objects in more complex multiple-object displays and provides additional evidence that infants represent the spatial location of moving occluded objects.     

Tractarian objects and logical categories

It has been much debated whether Tractarian objects are what Russell would have called particulars or whether they include also properties and relations. This paper claims that the debate is misguided: there is no logical category such that Wittgenstein intended the reader of the Tractatus to understand his objects either as providing examples of or as not providing examples of that category. This is not to say that Wittgenstein set himself against the very idea of a logical category: quite the contrary. However, where Russell presents his logical variety of particulars and the various types of universal, and Frege presents his of objects and the various types of function, Wittgenstein denies the propriety of such a priori expositions. Wittgenstein envisages a variety of logical types of entity but insists that the nature of these types is something to be discovered only through analysis. This research was conducted whilst holding a Jacobsen Research Fellowship at the University of London.     

Infants' categorization of novel objects with more or less obvious features

In five experiments, 14- to 15-month-old infants' categorization of objects on the basis of more or less obvious features was investigated. Using an object examining paradigm, a total of 200 infants were familiarized with novel objects that shared either more obvious features (i.e., easily visible) or less obvious features (i.e., accessible by lifting a flap), followed by an in-category object and an out-of-category object. When only perceptual information was available, infants formed a category on the basis of the more obvious features but not on the basis of the less obvious features (Experiments 1 and 3). When infants were provided with animacy cues and/or object names, they formed categories on the basis of either more or less obvious features (Experiments 2, 4, and 5). The results of these studies delineate the role of animacy cues and object names in establishing categories on the basis of less obvious features.     

Color-function categories that prime infants to use color information in an object individuation task

There is evidence for developmental hierarchies in the type of information to which infants attend when reasoning about objects. Investigators have questioned the origin of these hierarchies and how infants come to identify new sources of information when reasoning about objects. The goal of the present experiments was to shed light on this debate by identifying conditions under which infants’ sensitivity to color information, which is slow to emerge, could be enhanced in an object individuation task. The outcome of Experiment 1 confirmed and extended previous reports that 9.5-month-olds can be primed, through exposure to events in which the color of an object predicts its function, to attend to color differences in a subsequent individuation task. The outcomes of Experiments 2-4 revealed age-related changes in the nature of the representations that support color priming. This is exemplified by three main findings. First, the representations that are formed during the color-function events are relatively specific. That is, infants are primed to use the color difference seen in the color-function events to individuate objects in the test events, but not other color differences. Second, 9.5-month-olds can be led to form more abstract event representations, and then generalize to other colors in the test events if they are shown multiple pairs of colors in the color-function events. Third, slightly younger 9-month-olds also can be led to form more inclusive categories with multiple color pairs, but only when they are allowed to directly compare the exemplars in each color pair during the present events. These results shed light on the development of categorization abilities, cognitive mechanisms that support color-function priming, and the kinds of experiences that can increase infants’ sensitivity to color information.     

The use of stories as autistic objects

This paper reviews Frances Tustin's concept of the 'autistic object' and its development over the course of her writings. Clinical material from work with a 4-year-old boy is brought to suggest that the concept can usefully be extended to include such cultural artefacts as stories as well as the physical objects emphasized by Tustin. It is also emphasized that the awareness of reality which autistic objects are used to defend against refers both to internal as well as external reality. The paper argues that it is the function to which the object is put that is critical in determining whether or not it should be viewed as an autistic object.     

4.5-month-old infants’ learning, retention and use of object boundary information

4.5-month-old infants can use information learned from prior experience with objects to help determine the boundaries of objects in a complex visual scene (Needham, 1998; Needham, Dueker, & Lockhead, 2002). The present studies investigate the effect of delay (between prior experience and test) on infant use of such experiential knowledge. Results indicate that infants can use experience with an object to help them to parse a scene containing that object 24 (Experiment 1). Experiment 2 suggests that after 24 h infants have begun to forget some object attributes, and that this forgetting promotes generalization from one similar object to another. After a 72-h delay, infants did not show any beneficial effect of prior experience with one of the objects in the scene (Experiments 3A and B). However, prior experience with multiple objects, similar to an object in the scene, facilitated infant segregation of the scene 72 h later, suggesting that category information remains available in infant memory longer than experience with a single object. The results are discussed in terms of optimal infant benefit from prior experiences with objects.     

Infants' use of material properties to guide their actions with differently weighted objects

Two studies with 9‐, 11‐ and 13‐month‐old infants were conducted to investigate infants' ability to use an object's material properties to guide their object‐directed actions. In study 1, 9‐ and 11‐month‐old infants played in an exploration phase with two objects made of different materials, one very heavy and the other one light and playable. Subsequently, when given the choice between both objects in a preferential reaching task, only the 11‐month‐olds' used the object's material information to remember and choose the lighter object. In study 2, 11‐ and 13‐month‐old infants underwent the same exploration phase. In the test phase, novel objects made of the same materials were offered. The 13‐ but not the 11‐month‐olds chose the objects made from the same material as the lighter object in the exploration phase. Additionally, infants' performances in the reaching task were positively correlated with their exploratory behaviour during the exploration phase. Altogether, the studies show a developmental progression in the use of an object's material information to guide infants' action. The results are discussed in respect to infants' perception of object properties and their implications for the development of physical knowledge. Copyright © 2010 John Wiley & Sons, Ltd.     

The development of infants’ use of property-poor sounds to individuate objects

There is evidence that infants as young as 4.5 months use property-rich but not property-poor sounds as the basis for individuating objects (Wilcox, Woods, Tuggy, & Napoli, 2006). The current research sought to identify the age at which infants demonstrate the capacity to use property-poor sounds. Using the task of Wilcox et al., infants aged 7 and 9 months were tested. The results revealed that 9- but not 7-month-olds demonstrated sensitivity to property-poor sounds (electronic tones) in an object individuation task. Additional results confirmed that the younger infants were sensitive to property-rich sounds (rattle sounds). These are the first positive results obtained with property-poor sounds in infants and lay the foundation for future research to identify the underlying basis for the developmental hierarchy favoring property-rich over property-poor sounds and possible mechanisms for change.     

Asymmetrical responding to male versus female other-race categories in 9- to 12-month-old infants

Faces can be categorized along various dimensions including gender or race, an ability developing in infancy. Infant categorization studies have focused on facial attributes in isolation, but the interaction between these attributes remains poorly understood. Experiment 1 examined gender categorization of other-race faces in 9- and 12-month-old White infants. Nine- and 12-month-olds were familiarized with Asian male or female faces, and tested with a novel exemplar from the familiarized category paired with a novel exemplar from a novel category. Both age groups showed novel category preferences for novel Asian female faces after familiarization with Asian male faces, but showed no novel category preference for novel Asian male faces after familiarization with Asian female faces. This categorization asymmetry was not due to a spontaneous preference hindering novel category reaction (Experiment 2), and both age groups displayed difficulty discriminating among male, but not female, other-race faces (Experiment 3). These results indicate that category formation for male other-race faces is mediated by categorical perception. Overall, the findings suggest that even by 12 months of age, infants are not fully able to form gender category representations of other-race faces, responding categorically to male, but not female, other-race faces.     

The Effect of Size of Pupil on the Form and Color Fields

The construct validity of the Wallach-Kogan (W-K) creativity test was investigated through an hierarchical factor analysis of intercorrelations among intelligence, creativity, control, and criterion variables for 73 Ss enrolled in grades 3 and 4 of an inner-city parochial school. The results provided considerable support for W-K's theoretical formulations. Creativity and intelligence assessors defined separate domains and remained totally resilient to merger into a superordinate factor. The creativity domain, which was defined by W-K subtests and criterion ratings, included the following factors: general, visual, and verbal creativity plus a weak methods factor for crayon drawings. The intelligence domain, which was defined by WISC subtests, included a relatively strong g factor and the following four primary factors: verbal precision, freedom from distractibility, perceptual organization, and quasi-specific.     

Infants' ability to categorise on the basis of rhyme

Two experiments are described, which investigated 7 - to 13-month-old infants' abilities to categorise syllables according to their ending sounds, or rhymes. Using the Conditioned Headturn (CHT) Procedure, infants were conditioned to turn their head when one set of rhyming CVCs changed to another set of rhyming CVCs. Even the 7 -month-old infants demonstrated an ability to categorise according to rimes. The infants could be separated into three different groups: those who conditioned but did not succeed in a rhyming task; those who succeeded at one rhyming task but not a second; and those infants who succeeded on two rhyming tasks. The infants in the second group were showing an early sensitivity to rhyme. However, they appeared to be learning a very specific rule, listening only for one category of rhyme. The third group of infants was able to extend the initial rule they learned to include new rhymes. This group learned not only to highlight one particular rhyme, but were also able to abstract the previously learned rule to new rhymes, thereby demonstrating a higher level of sophistication in their categorisation of rhymes. These results are discussed in relation to the ontogeny of language learning, and work demonstrating a relationship between rhyming ability and competence in reading and writing.     

Eccentricity biases of object categories are evident in visual working memory

In high-order object areas, face-selective areas prefer centrally presented stimuli, whereas building-selective areas prefer peripherally presented stimuli (Levy et al., 2001). We investigated whether this eccentricity bias was also evident in visual working memory. In Experiment 1, we found that working memory performance for faces decreased towards the periphery while the performance for buildings remained unchanged across different eccentricities. To rule out the possibility that lower level features influence these results, we manipulated the spatial frequency of faces and buildings (Experiment 2) and the spatial layout information of the buildings (Experiment 3). In both of the experiments, we replicated the results of Experiment 1, even when these lower level features of stimuli were controlled. Consistent with previous findings, the current results suggest that each object category is processed in a different manner depending on the eccentricity. This eccentricity bias is likely the result of how the high-order object areas represent different object categories.     

Establishing visual category boundaries between objects: a PET study

Individuals with Alzheimer's disease (AD) often have problems in recognizing common objects. This visual agnosia may stem from difficulties in establishing appropriate visual boundaries between visually similar objects. In support of this hypothesis, showed that AD subjects have difficulties in establishing visual category boundaries between continuously graded shapes. In an attempt to investigate the neural basis of these impairments, the current study required a group of neurologically healthy elderly participants to categorically classify a series of ellipses varying in width while regional blood flow changes were measured using positron emission tomography (PET). Two categorization conditions were compared in order to isolate changes in cortical activity that dissociated the categorization of shapes situated either near or far from a category boundary that divided the width continuum. The participants produced a discontinuity in the probability and speed of categorizing the shapes at some point along the continuum, suggesting that the objects were classified into distinct categories. Moreover, a comparison of the PET scans obtained while the subjects were categorizing the shapes situated near vs. far form the category boundary revealed significant differences in cortical activity in the parietal and frontal brain areas. These findings suggest that both visuo-spatial and decision making mechanisms may be involved in establishing categorical distinctions between continuously graded stimuli. It is proposed that the functional role of the parietal and frontal cortical regions in establishing visual boundaries between categories of objects may be relevant for understanding object recognition impairments in AD.     

A direct comparison of infants' use of featural and spatiotemporal information when individuating objects in a non-occlusion event-monitoring design

A central issue within the field of object individuation concerns the kind of information that infants rely on when they succeed in individuating objects. By means of the violation-of-expectation strategy, the present study reports a comparison of 8.0- and 6.5-month-old infants' use of featural and spatiotemporal information in a new non-occlusion event-monitoring design. Using a mirror setup the memory demands were minimized, because all apparent changes in the unexpected test events took place in full view of the infants. The results indicate that the 8.0- and 6.5-month-old infants individuated objects successfully regardless of whether they were provided with featural or spatiotemporal information. The results are discussed in relation to the relevant literature.     

Infants' perception of concavity and convexity of shaded objects

The discriminative sensitivities of 30 4‐month‐old and 30 8‐month‐old infants for concave and convex objects were measured using the preferential‐looking method. Five cylinder‐like objects with different magnitudes of concave or convex shaded surfaces and outline contours were presented to the infants in pairs. The results indicated that the 4‐month‐old infants could discriminate better between object convexities than between object concavities. In contrast, the 8‐month‐old infants were able to equally discriminate between object concavities and object convexities, and their sensitivity to both object concavity/convexity was much higher than that of the 4‐month‐old infants. This difference in the sensitivity to object concavity and convexity suggested that younger and older infants might have differential abilities for cue utilization for recovering object structures.     

Transport and use of common objects: Influence of weight on action planning

Internal knowledge and visual cues about object's weight play an important role in grasping and lifting objects. It has been shown that both visual cues and internal knowledge might influence movement kinematics and force production depending on action goal (use vs. transport). However, there is little evidence about weight's influence on action planning as reflected by initiation time. In the present study we investigated this issue. In Experiment 1, participants had to grasp light and heavy objects (without moving them) to either use or transport them. In Experiment 2 we asked another group of participants to actually use or transport the same objects. We observed that initiation times were faster for heavy objects than for light objects in both the transport and use tasks, but only in Experiment 2. Thus, weight influenced the planning of use and transport actions, only when the end-goal of the action was really achieved. These data are incompatible with the hypothesis that only use actions are supported by stored object's representations. They rather suggest that in some circumstances, depending of the end-goal of the action and the physical constraints the planning of both use and transport actions are based on stored object representation.     

Infants' use of category knowledge and object attributes when segregating objects at 8.5 months of age

The current research investigates infants' perception of a novel object from a category that is familiar to young infants: key rings. We ask whether experiences obtained outside the lab would allow young infants to parse the visible portions of a partly occluded key ring display into one single unit, presumably as a result of having categorized it as a key ring. This categorization was marked by infants' perception of the keys and ring as a single unit that should move together, despite their attribute differences. We showed infants a novel key ring display in which the keys and ring moved together as one rigid unit (Move-together event) or the ring moved but the keys remained stationary throughout the event (Move-apart event). Our results showed that 8.5-month-old infants perceived the keys and ring as connected despite their attribute differences, and that their perception of object unity was eliminated as the distinctive attributes of the key ring were removed. When all of the distinctive attributes of the key ring were removed, the 8.5-month-old infants perceived the display as two separate units, which is how younger infants (7-month-old) perceived the key ring display with all its distinctive attributes unaltered. These results suggest that on the basis of extensive experience with an object category, infants come to identify novel members of that category and expect them to possess the attributes typical of that category.     

Patterns of 4-month-old infant responses to hidden silent and sounding people and objects

Responses of 4-month-old infants to hidden people and objects were investigated with equated task demands. Twenty-one 4-month-old infants were administered a combined task, in which they were shown a sounding stimulus that continued to sound after hiding, an auditory task, in which sound was the only source of information about the position of the object in space, and a vision task, in which a silent stimulus was shown to the infants prior to hiding. Five infant behaviours were coded: reaching, gazing, body movements, vocalizations and smiles. The infants reached significantly more for hidden objects than for people, to whom they vocalized instead. They further smiled, and moved their bodies more towards their invisible mother than to the other stimuli. Thus infants responded differentially to people and objects whether the stimuli were soundless (so that there was no cue to their presence) or not. This suggested that infants appreciated (a) that an object had been hidden; (b) this object was either animate or inanimate; and (c) different procedures were appropriate for the retrieval of, or for interacting with animate and inanimate objects. Discussion centres on the underlying representational system that allows for such appreciation.