Multisensory exploration and object individuation in infancy

Recent research indicates that by 4.5 months, infants use shape and size information as the basis for individuating objects but that it is not until 11.5 months that they use color information for this purpose. The present experiments investigated the extent to which infants' sensitivity to color information could be increased through select experiences. Five experiments were conducted with 10.5- and 9.5-month-olds. The results revealed that multimodal (visual and tactile), but not unimodal (visual only), exploration of the objects prior to the individuation task increased 10.5-month-olds' sensitivity to color differences. These results suggest that multisensory experience with objects facilitates infants' use of color information when individuating objects. In contrast, 9.5-month-olds did not benefit from the multisensory procedure; possible explanations for this finding are explored. Together, these results reveal how an everyday experience--combined visual and tactile exploration of objects--can promote infants' use of color information as the basis for individuating objects. More broadly, these results shed light on the nature of infants' object representations and the cognitive mechanisms that support infants' changing sensitivity to color differences.     

Textons, visual pop-out effects, and object recognition in infancy.

Five experiments were conducted to determine whether primitive perceptual features, or textons, which Julesz (1984) identified in studies of texture segregation with adults, also affect object recognition early in development. Three-month-old infants discriminated Ts and Ls composed of overlapping line segments from +s but not from each other in a delayed-recognition test after 24 hr; however, Ts and Ls were discriminated from each other after only 1 hr. In a priming paradigm, Ts, Ls, and +s were discriminated from one another after 2 weeks. In succeeding experiments, infants exhibited adultlike visual pop-out effects in both delayed recognition and priming paradigms, detecting an L in the midst of 6 +s and vice versa; these effects were symmetrical. The pop-out effects apparently resulted from parallel search: Infants failed to detect 3 Ls among 4 +s. Clearly, some of the same primitive units that have been identified as the building blocks of adult visual perception underlie object recognition early in infancy.     

Figural goodness,stimulus heterogeneity,similarity and object segregation in infancy

The segregation of objects from other objects in visual arrays is a fundamental function of our visual system. Research suggests that adults’ detection of a target among nontargets is affected by the heterogeneity of array elements and the resulting changes in target–nontarget and nontarget–nontarget similarities. We examined the effects of heterogeneity and similarity on object segregation in infancy. In Experiment 1, 5.5‐month‐olds detected a misoriented element in an array when the array elements were spatially arranged in a ‘good’ configuration but not when they were arranged in a ‘poor’ configuration. In Experiment 2, infants detected a vertical line in a homogeneous array of 55° or 125° lines, but failed to do so in a heterogeneous array of 55° and 125° lines. Thus, heterogeneity in both the arrangement and identity of array elements affected infants’ discrepancy detection. Because the average target–nontarget similarity was the same in the two conditions of Experiment 2, the results also indicated that nontarget–nontarget similarity independently affects discrepancy detection in infancy. These results are consistent with models of object segregation by adults, and suggest that stimulus heterogeneity and similarity have analogous effects on object segregation at 5.5 months of age and in adulthood.     

Object representation and predictive action in infancy

Previous research has shown that 6‐month‐old infants extrapolate object motion on linear paths when they act predictively on fully visible moving objects but not when they observe partly occluded moving objects. The present research probed whether differences in the tasks presented to infants or in the visibility of the objects account for these findings, by investigating infants’ predictive head tracking of a visible object that moves behind a small occluder. Six‐month‐old infants were presented with an object that moved repeatedly on linear or nonlinear paths, with an occluder covering the place where all the paths intersected. The first time infants viewed an object’s motion, their head movements did not anticipate either linear or nonlinear motion, but they quickly learned to anticipate linear motion on successive trials. Infants also learned to anticipate nonlinear motion, but this learning was slower and less consistent. Learning in all cases concerned the trajectory of the object, not the specific locations at which the object appeared. These findings suggest that infants form object representations that are weakly biased toward inertial motion and that are influenced by learning. The findings accord with the thesis that a single system of representation underlies both predictive action and perception of object motion, and that occlusion reduces the precision of object representations.     

A review of object individuation in infancy

The present review of object individuation in infancy is divided into five sections. The first section is a brief history of the field and an outline of the development of efficient methods for studying object individuation among infants. Sections 2 and 3 are structured around the empirical evidence obtained by using two different kinds of basic and widely used experiments: infants' responses to (apparently) disappearing objects (Section 2), and infants' responses to objects that (apparently) change into other objects (Section 3). In the fourth section, theories of object individuation are presented and discussed. The final section takes a look ahead to the future and proposes a few experiments that may help in resolving some of the most important disputes regarding object individuation in infancy.     

Image representation,scaling and cognitive model of object perception

Neuropsychological investigations of visual imagery and representations have led to a deeper understanding of the spatial perception, representation and memory. But how each individual perceives object’s geometrical properties and how they differ from person to person, both under event-related memory and normal recollecting memory in the presence or in the absence of direct sensory stimulation is still unclear. Spatial knowledge is diverse, complex, and multi-modal, as are the situations in which it is used. All seem to agree that a cognitive map is a mental representation of an external environment. The image scaling is important in understanding the psychological dysfunctions of patients suffering from spatial cognition problems. The scaling becomes self-evident in art forms, when people are asked to draw image of objects they see actively or from their short or long term memory. In this paper we develop a comprehensive model of this scaling factor and its implications in spatial image representation and memory. We also extend its notion in understanding the perception of objects whose representations are normally not possible (like the perception of universal scales, infinities and parallel lines) but are well comprehended by the human brains. Here we give a scaling factor which is variable depending on the situations for a person based on his visual memory and drawing capabilities. And then extend it to analyse his cognitive strengths, disorders and any imperfections. This model also helps in formalizing the architectural cognitive maps needed to change the scaling factor, depending on the types of visual works one performs.     

Comment on Hofsten and Spelke, object perception and object-directed reaching in infancy

Hofsten and Spelke (1985) reported a series of studies that quite clearly demonstrated infant sensitivity to depth and relative motion cues. They suggest a salience hierarchy for those cues in which relative motion takes precedence over depth when both cues are present. Based on reports that infants reach for and grasp boundaries in the visual display, the authors make the further claim that these data argue for object perception infants by the time they are 5 months old. The present article argues against this claim on two grounds: First, the authors do not report that infants specifically reached and grasped at boundaries in the display. Second, although patterns of reach are clearly affected by changes in boundary cues, there is no evidence that the boundaries the infants perceive are necessarily object boundaries.     

Conceptual structures, representation of objects and object relations]

This article provides an overview of psychological studies of object concepts, highlighting the more recent re-conceptualizations, and the latest developments in research in this field. These developments have tended to focus on the notion of context, as well as on the notion of causal relations between features. Our theoretical analysis of this field is backed up by experimental illustrations. We complete with an examination of "category-specific impairments" studies, in the light of the evolution of concept theories.     

Object individuation and object identity in infancy: the role of spatiotemporal information, object property information, and language.

Recent work on object individuation and object identity in infancy indicates that at least three sources of information may be used for object individuation and object identity: spatiotemporal information, object property information, and object kind information. Several experiments have shown that a major developmental change occurs between 10 and 12 months of age (Xu & Carey, 1996; Xu, Carey & Welch, in press; Van de Walle, Prevor & Carey, under review; Xu, Carey & Quint, in preparation): Infants at 10 months and younger readily use spatiotemporal information in object individuation and object identity tasks, but not until about 12 months of age are infants able to use object property or object kind information to do so. This paper proposes a two-part conjecture about the mechanism underlying this change. The first part borrows ideas from object-based attention and the distinction between "what" and "where" information in visual processing. The hypothesis is that (1) young infants encode object motion and location information separately from object property information; and (2) toward the end of the first year, infants integrate these two sources of information. The second part of the conjecture posits an important role for language. Infants may take distinct labels as referring to distinct kinds of objects from the onset of word learning, and infants use this information in solving the problem of object individuation and object identity. Evidence from human adults, infants, and non-human primates is reviewed to provide support for the conjecture.     

The emergence of kind-based object individuation in infancy

Four experiments investigated whether 12-month-old infants use perceptual property information in a complex object individuation task, using the violation-of-expectancy looking time method (Xu, 2002; Xu & Carey, 1996). Infants were shown two objects with different properties emerge and return behind an occluder, one at a time. The occluder was then removed, revealing either two objects (expected outcome, if property differences support individuation) or one object (unexpected outcome). In Experiments 1-3, infants failed to use color, size, or a combination of color, size, and pattern differences to establish a representation of two distinct objects behind an occluder. In Experiment 4, infants succeeded in using cross-basic-level-kind shape differences to establish a representation of two objects but failed to do so using within-basic-level-kind shape differences. Control conditions found that the methods were sensitive. Infants succeeded when provided unambiguous spatiotemporal information for two objects, and they encoded the property differences during these experiments. These findings suggest that by 12 months, different properties play different roles in a complex object individuation task. Certain salient shape differences enter into the computation of numerical distinctness of objects before other property differences such as color or size. Since shape differences are often correlated with object kind differences, these results converge with others in the literature that suggest that by the end of the first year of life, infants' representational systems begin to distinguish kinds and properties.     

Parts function as perceptual organizational entities in infancy

Both objects and parts function as organizational entities in adult perception. Prior research has indicated that objects affect organization early in life: Infants grouped elements located within object boundaries and segregated them from those located on different objects. Here, we examined whether parts also induce grouping in infancy. Five- and 6.5-month-olds were habituated to two-part objects containing element pairs. In a subsequent test, infants treated groupings of elements that crossed part boundaries as novel, in comparison with groupings that had shared a common part during habituation. In contrast, the same arrangement of elements failed to elicit evidence of grouping in control conditions in which the elements were not surrounded by closed part boundaries. Thus, infants grouped and segregated elements on the basis of part structure. Part-based processing is a key aspect of many theories of perception. The present research adds to this literature by indicating that parts function as organizational entities early in life.     

Episodic representation of diagnostic and nondiagnostic object colour

In three experiments, we investigated transsaccadic object file representations. In each experiment, participants moved their eyes from a central fixation cross to a saccade target located between two peripheral objects. During the saccade, this preview display was replaced with a target display containing a single object to be named. On trials in which the target identity matched one of the preview objects, its colour either matched or did not match the previewed object colour. The results indicated that colour changes disrupt perceptual continuity, but only for the class of objects for which colour is diagnostic of object identity. When the colour is not integral to identifying an object (for example, when the object is a letter or an object without a characteristic colour), object continuity is preserved regardless of changes to the object's colour. These results suggest that object features that are important for defining the object are incorporated into its episodic representation. Furthermore, the results are consistent with previous work showing that the quality of a feature's representation determines its importance in preserving continuity.     

Past experience influences object representation in working memory

The nature of object representation in working memory is vital to establishing the capacity of working memory, which in turn shapes the limits of visual cognition and awareness. Although current theories discuss whether representations in working memory are feature-based or object-based, no theory has considered the role of past experience. However, work with humans and non-human primates suggests that once participants learn which features are important for category membership, these diagnostic features become more salient than non-diagnostic features in long-term memory and object recognition. Critically, the brain areas involved in this diagnosticity effect are also recruited during working memory tasks. We report two experiments testing whether a diagnosticity effect exists in working memory; and whether it is present when visual information is encoded into working memory, or if it is the result of maintenance within working memory. Results showed a diagnosticity effect which was present at encoding. Maintenance did not influence the nature of object representation in working memory. These findings show that the meaning we glean from our past experience has a profound influence on the nature of object representation in working memory.     

Cohesion as a constraint on object persistence in infancy

A critical challenge for visual perception is to represent objects as the same persisting individuals over time and motion. Across several areas of cognitive science, researchers have identified cohesion as among the most important theoretical principles of object persistence: An object must maintain a single bounded contour over time. Drawing inspiration from recent work in adult visual cognition, the present study tested the power of cohesion as a constraint as it operates early in development. In particular, we tested whether the most minimal cohesion violation - a single object splitting into two - would destroy infants' ability to represent a quantity of objects over occlusion. In a forced-choice crawling paradigm, 10- and 12-month-old infants witnessed crackers being sequentially placed into containers, and typically crawled toward the container with the greater cracker quantity. When one of the crackers was visibly split in half, however, infants failed to represent the relative quantities, despite controls for the overall quantities and the motions involved. This result helps to characterize the fidelity and specificity of cohesion as a fundamental principle of object persistence, suggesting that even the simplest possible cohesion violation can dramatically impair infants' object representations and influence their overt behavior.     

物体表征强度对基于动态物体的注意的影响

基于物体的注意已得到许多静态物体实验的证实, 然而, 对注意分配如何受动态物体影响的研究较少, 存在提示物体假设和动态更新假设两种观点。提示物体假设认为基于物体的注意由最初的物体决定, 而动态更新假设则认为由变化之后的物体决定。动态物体的注意研究还发现了即时物体效应, 即注意基于新物体进行。对于物体变化时注意究竟基于旧物体还是新物体, 新旧物体的相对物体表征强度在其中起决定作用; 当提示物体表征较强时表现为提示物体(即旧物体)决定注意分配, 而当即时物体表征较强时表现为即时物体(即新物体)决定注意分配。相对物体表征强度的概念对理解物体动态变化情况下基于物体的注意的分配以及解决相关理论之冲突可能有重要作用。     

Object recognition and object segregation in infancy: historical perspective, theoretical significance, "kinds" of knowledge, and relation to object categorization

Needham (2001, this issue) reports that 4.5-month-old infants can use a short-term familiarization experience with a single object to facilitate the segregation of a visual display consisting of a configurally similar object and a configurally dissimilar adjacent object. We reflect on this finding in the larger context of Needham's systematic research on the development of object perception, a program that has included (1) a series of empirical studies designed to identify the different cues that infants use for object segregation and (2) a theoretical framework in which infants are presumed to integrate these cues to form interpretations of complex visual displays.     

Priorities for representation: Task settings and object interaction both influence object memory

Following an active task, the memory representations for used and unused objects are different. However, it is not clear whether these differences arise due to prioritizing objects that are task-relevant, objects that are physically interacted with, or a combination of the two factors. The present study allowed us to tease apart the relative importance of task-relevance and physical manipulation on object memory. A paradigm was designed in which objects were either necessary to complete a task (target), moved out of the way (obstructing, but interacted with), or simply present in the environment (background). Participants’ eye movements were recorded with a portable tracker during the task, and they received a memory test on the objects after the task was completed. Results showed that manipulating an object is sufficient to change how information is extracted and retained from fixations, compared to background objects. Task-relevance provides an additional influence: information is accumulated and retained differently for manipulated target objects than manipulated obstructing objects. These findings demonstrate that object memory is influenced both by whether we physically interact with an object, and the relevance of that object to our behavioral goals.     

The role of color diagnosticity in object recognition and representation

The role of color diagnosticity in object recognition and representation was assessed in three Experiments. In Experiment 1a, participants named pictured objects that were strongly associated with a particular color (e.g., pumpkin and orange). Stimuli were presented in a congruent color, incongruent color, or grayscale. Results indicated that congruent color facilitated naming time, incongruent color impeded naming time, and naming times for grayscale items were situated between the congruent and incongruent conditions. Experiment 1b replicated Experiment 1a using a verification task. Experiment 2 employed a picture rebus paradigm in which participants read sentences one word at a time that included pictures of color diagnostic objects (i.e., pictures were substituted for critical nouns). Results indicated that the “reading” times of these pictures mirrored the pattern found in Experiment 1. In Experiment 3, an attempt was made to override color diagnosticity using linguistic context (e.g., a pumpkin was described as painted green). Linguistic context did not override color diagnosticity. Collectively, the results demonstrate that color information is regularly utilized in object recognition and representation for highly color diagnostic items.