Transfer and scaffolding of perceptual grouping occurs across organizing principles in 3- to 7-month-old infants

Connection-based and object-based grouping in multiple-object tracking: A developmental study

Developmental research on Gestalt laws has previously revealed that, even as young as infancy, we are bound to group visual elements into unitary structures in accordance with a variety of organizational principles. Here, we focus on the developmental trajectory of both connection-based and object-based grouping, and investigate their impact on object formation in participants, aged 9-21 years old (N = 113), using a multiple-object tracking paradigm. Results reveal a main effect of both age and grouping type, indicating that 9- to 21-year-olds are sensitive to both connection-based and object-based grouping interference, and tracking ability increases with age. In addition to its importance for typical development, these results provide an informative baseline to understand clinical aberrations in this regard. Statement of contribution What is already known on this subject? The origin of the Gestalt principles is still an ongoing debate: Are they innate, learned over time, or both? Developmental research has revealed how each Gestalt principle has its own trajectory and unique relationship to visual experience. Both connectedness and object-based grouping play an important role in object formation during childhood. What does this study add? The study identifies how sensitivity to connectedness and object-based grouping evolves in individuals, aged 9-21 years old. Using multiple-object tracking, results reveal that the ability to track multiple objects increases with age. These results provide an informative baseline to understand clinical aberrations in different types of grouping.

Size and orientation cue figure-ground segregation in infants

Adult perceivers segregate figure from ground based on image cues such as small size and main axis orientation. The current study examined whether infants can use such cues to perceive figure-ground segregation. Three- to 7-month-olds were familiarized with a pie-shaped stimulus in which some pieces formed a + and other pieces formed an x. The infants were then presented with a novelty preference test pairing the + and x. The bases for the pieces forming the + or x were size and orientation (Experiment 1), size (Experiment 2), and orientation (Experiment 3). In each experiment, infants responded as if they recognized as familiar the shape specified by small size, main axis orientation, or their combination. Control conditions showed that infant performance could not be attributed to spontaneous preference. The findings suggest that infants can achieve figure-ground segregation based on some of the same cues used by adults.

Prior Knowledge of Object Associations Shapes Attentional Templates and Information Acquisition

Studies on attentional selection typically use unpredictable and meaningless stimuli, such as simple shapes and oriented lines. The assumption is that using these stimuli minimizes effects due to learning or prior knowledge, such that the task performance indexes a "pure" measure of the underlying cognitive ability. However, prior knowledge of the test stimuli and related stimuli acquired before or during the task impacts performance in meaningful ways. This mini review focuses on prior knowledge of object associations, because it is an important, yet often ignored, aspect of attentional selection. We first briefly review recent studies demonstrating that how objects are selected during visual search depends on the participant's prior experience with other objects associated with the target. These effects appear with both task-relevant and task-irrelevant knowledge. We then review how existing object associations may influence subsequent learning of new information, which is both a driver and a consequence of selection processes. These insights highlight the importance of one aspect of prior knowledge for attentional selection and information acquisition. We briefly discuss how this work with young adults may inform other age groups throughout the lifespan, as learners gradually increase their prior knowledge. Importantly, these insights have implications for developing more accurate measurements of cognitive abilities.

Naming influences 9-month-olds' identification of discrete categories along a perceptual continuum

A growing body of evidence documents that naming guides 9-month-old infants as they organize their visual experiences into categories. In particular, this evidence reveals that naming highlights categories when these are visually distinct. Here we advance this work in by introducing an anticipatory looking design to assess how naming influences infants' categorization of objects that vary along a perceptual continuum. We introduced 9-month-old infants (n = 48) to continua of novel creature-like objects. During the learning phase, infants had an opportunity to observe that objects from one end of the perceptual continuum moved to the left and objects from the other end moved to the right. What varied was how the objects were named. Infants in theone-name condition heard the same novel noun applied to all objects along the continuum; those in the two-name condition heard one name for objects from one end of the continuum and a second name for objects at the other end. At test, all infants viewed new objects from the same continuum. At issue was whether infants would anticipate the side to which the test objects would move and whether their expectations varied as a function of naming condition. Infants in the one-name condition formed a single overarching category and therefore searched for new test objects at either location; those in the two-name condition discerned two categories and therefore correctly anticipated the likely location of the test objects, whether these were close to the poles or to the center of the continuum. This provides the first evidence that by 9 months, naming supports both the number of categories infants impose along a perceptual continuum and the clarity of the category boundaries.

A neural signature of rapid category-based target selection as a function of intra-item perceptual similarity, despite inter-item dissimilarity

Previous work on visual search has suggested that only a single attentional template can be prioritized at any given point in time. Grouping features into objects and objects into categories can facilitate search performance by maximizing the amount of information carried by an attentional template. From infancy to adulthood, earlier studies on perceptual similarity have shown that consistent features increase the likelihood of grouping features into objects (e.g., Quinn & Bhatt, Psychological Science. 20:933-938, 2009) and objects into categories (e.g., shape bias; Landau, Smith, & Jones, Cognitive Development. 3:299-321, 1988). Here we asked whether lower-level, intra-item similarity facilitates higher-level categorization, despite inter-item dissimilarity. Adults participated in four visual search tasks in which targets were defined as either one item (a specific alien) or a category (any alien) with either similar features (e.g., circle belly shape and circle back spikes) or dissimilar features (e.g., circle belly shape and triangle back spikes). Using behavioral and neural measures (i.e., the N2pc event-related potential component, which typically emerges 200 ms poststimulus), we found that intra-item feature similarity facilitated categorization, despite dissimilar features across the category items. Our results demonstrate that feature similarity builds novel categories and activates a task-appropriate abstract categorical search template. In other words, grouping at the lower, item level facilitates grouping at the higher, category level, which allows us to overcome efficiency limitations in visual search.

Object labeling influences infant phonetic learning and generalization

Different kinds of speech sounds are used to signify possible word forms in every language. For example, lexical stress is used in Spanish (/'be.be/, 'he/she drinks' versus /be.'be/, 'baby'), but not in French (/'be.be/ and /be.'be/ both mean 'baby'). Infants learn many such native language phonetic contrasts in their first year of life, likely using a number of cues from parental speech input. One such cue could be parents' object labeling, which can explicitly highlight relevant contrasts. Here we ask whether phonetic learning from object labeling is abstract-that is, if learning can generalize to new phonetic contexts. We investigate this issue in the prosodic domain, as the abstraction of prosodic cues (like lexical stress) has been shown to be particularly difficult. One group of 10-month-old French-learners was given consistent word labels that contrasted on lexical stress (e.g., Object A was labeled /'ma.bu/, and Object B was labeled /ma.'bu/). Another group of 10-month-olds was given inconsistent word labels (i.e., mixed pairings), and stress discrimination in both groups was measured in a test phase with words made up of new syllables. Infants trained with consistently contrastive labels showed an earlier effect of discrimination compared to infants trained with inconsistent labels. Results indicate that phonetic learning from object labeling can indeed generalize, and suggest one way infants may learn the sound properties of their native language(s).

The development of individuation in autism

Evidence suggests that people with autism rely less on holistic visual information than typical adults. The current studies examine this by investigating core visual processes that contribute to holistic processing--namely, individuation and element grouping--and how they develop in participants with autism and typically developing (TD) participants matched for age, IQ, and gender. Individuation refers to the ability to "see" approximately four elements simultaneously; grouping elements can modify how many elements can be individuated. We examined these processes using two well-established paradigms, rapid enumeration and multiple object tracking (MOT). In both tasks, a performance limit of four elements in typical adults is thought to reflect individuation capacity. Participants with autism displayed a smaller individuation capacity than TD controls, regardless of whether they were enumerating static elements or tracking moving ones. To manipulate the holistic information available via element grouping, elements were arranged into a design in rapid enumeration, or moved together in MOT. Performance in participants with autism was affected to a similar degree as TD participants by element grouping, whether the manipulation helped or hurt performance, consistent with evidence that some types of gestalt/grouping information are processed typically in autism. There was substantial development from childhood to adolescence in the speed of individuation in those with autism, but not from adolescence to adulthood, a pattern distinct from TD participants. These results reveal how core visual processes function in autism, and provide insight into the architecture of vision (i.e., individuation appears distinct from visual strengths in autism, such as visual search).

How does Learning Impact Development in Infancy? The Case of Perceptual Organization

Pattern perception and organization are critical functions of the visual cognition system. Many organizational processes are available early in life, such that infants as young 3 months of age are able to readily utilize a variety of cues to organize visual patterns. However, other processes are not readily evident in young infants, and their development involves perceptual learning. We describe a theoretical framework that addresses perceptual learning in infancy and the manner in which it affects visual organization and development. It identifies five kinds of experiences that induce learning, and suggests that they work via attentional and unitization mechanisms to modify visual organization. In addition, the framework proposes that this kind of learning is abstract, domain general, functional at different ages in a qualitatively similar manner, and has a long-term impact on development through a memory reactivation process. Although most models of development assume that experience is fundamental to development, very little is actually known about the process by which experience affects development. The proposed framework is an attempt to account for this process in the domain of perception.

Part perception in infancy: sensitivity to the short-cut rule

Research indicates that object perception involves the decomposition of images into parts. A critical principle that governs part decomposition by adults is the short-cut rule, which states that, all else being equal, the visual system parses objects using the shortest possible cuts. We examined whether 6.5-month-olds' parsing of images also follows the short-cut rule. Infants in the experimental conditions were habituated to cross shapes and then tested for their preference between segregated patterns produced using long cuts versus short cuts. Infants in the control conditions were directly tested with the segregated patterns. Infants in the experimental conditions exhibited a greater novelty preference for the long-cut over the short-cut patterns than did those in the control conditions, thereby indicating that they are more likely to segregate cross shapes using short cuts rather than long cuts. This sensitivity to the short-cut rule was evident when two alternative parameters, part area and protrusion, were controlled in Experiments 1 and 2, respectively. Thus, a critical principle that governs part segregation in adulthood is operational by 6.5 months of age.