Lisa M. Oakes

Integrating Language and Gesture in Infancy

Whether language/gesture correlations in early language development can be explained by parallelism or comprehension mediation was examined. Study 1, parental report data for 95 l-year-olds, suggested that word comprehension and production are dissociated in this age range and that the comprehension and production factors map onto distinct aspects of gesture. Study 2 tested 41 13-15month-olds in a task in which the modeled gesture was accompanied by supportive, contradictory, or neutral narratives. Results showed that infants can use adult speech as an aid in reproduction of modeled gestures (comprehension mediation). However, there is still additional variance in gestural production that correlates with expressive vocabulary when comprehension-related variance is removed. Thus, comprehension mediation and parallelism both appear to be operating.

Infants' object examining: Habituation and categorization

Abstract The visual habituation paradigm has dominated the study of infant object discrimination and categorization. A more active task, object examining, was used in two studies to explore early discrimination and categorization, and to validate previous findings. The object-examining task combined active exploration of real objects with some aspects of a habituation-dishabituation paradigm. The first study explored simple discrimination. Six- and 10-month-old infants were familiarized with a single object and then tested with two novel objects. The results indicated that at both ages, infants showed clear discrimination among objects. The second study explored infant categorization and revealed that when both 6- and 10-month-old infants were familiarized with a category of objects, they responded to novel objects in terms of their categorical membership. These results converge with previous findings obtained by using more traditional methods, and demonstrate the utility of an object-examining task for the exploration of cognitive abilities in the first year of life. Finally, a comparison of two different measures of attention used in this task, examining and looking, revealed that examining time was a better measure of active processing of information about objects than was looking time.

Rapid Development of Feature Binding in Visual Short-Term Memory

The binding of object identity (color) and location in visual short-term memory (VSTM) was examined in 6.5- to 12.5-month-old infants (N = 144). Although we previously found that by age 6.5 months, infants can represent both color and location in VSTM, in the present study we observed that 6.5-month-old infants could not remember trivially simple color-location combinations across a 300-ms delay. However, 7.5-month-old infants could bind color and location as effectively as 12.5-month-old infants. Control conditions confirmed that the failure of 6.5-month-old infants was not a result of perceptual or attentional limitations. This rapid development of VSTM binding between 6.5 and 7.5 months occurs during a period of rapid increase in VSTM storage capacity and just after a period of dramatic neuroanatomical changes in parietal cortex. Thus, the ability to bind features and the ability to store multiple objects may both depend on a process that is mediated by posterior parietal cortex and is perhaps related to focused attention.

Language and hand preference in early development

Although there is a demonstrated bias toward use of the right hand from birth, the meaning of this bias and its stability over time are unclear. Within a longitudinal study of language development at 13,20, and 28 months, we extracted information about unimanual and bimanual hand preference from videotapes. Both unimanual and bimanual actions on objects were divided into symbolic (e.g., pretend play) and nonsymbolic (e.g., picking up and putting down). A separate count was made of communicative pointing gestures. Children showed a marked right‐hand bias (70%) across categories, a bias that did not differ as a function of age, sex, or unimanual or bimanual type. However, preference for the right hand was stronger for symbolic than for nonsymbolic movements in both unimanual and bimanual activity. At 13 and 28 months, there was a significantly greater right‐hand bias in pointing than in any other manual activity. Total right‐hand bias at 13 months was significantly correlated with analytic/ receptive aspect...

A Longitudinal Investigation of the Development of Attention and Distractibility

We longitudinally investigated the development of endogenous control of attention in 2 types of tasks that involve competition for attentional focus at 7, 9, and 31 months of age. At all 3 sessions, children participated in a multiple object free play task and a distractibility task. The results revealed both developmental differences and continuity of attentional skills. There was clear evidence of stability in distractibility between 9 and 31 months, and infant distractibility measures were related to toddler attention in the multiple object free play task. The results are discussed in terms of the development of endogenous control of attention and the underlying processes that may guide stability in attentional control.

Using Habituation of Looking Time to Assess Mental Processes in Infancy

Habituation of looking time has become the standard method for studying cognitive processes in infancy. This method has a long history and derives from the study of memory and habituation itself. Often, however, it is not clear how researchers make decisions about how to implement habituation as a tool to study processes such as categorization, object representation, and memory. This article describes the challenges for implementing this tool and describes a set of best practices for its use to study perception and cognition in infancy.

The Development of Attention and Its Relations to Language in Infancy and Toddlerhood

We investigated longitudinally the development of attention in two free-play tasks and the relation between attention in those tasks and language ability in toddlerhood. We observed developmental differences in attention from 9 and 31 months both as children investigated a single object and as they investigated multiple objects. Attention in these contexts at 9 months was differentially related to vocabulary at 31 months, but concurrent measures of attention at 31 months were not related to vocabulary at that age. The results are discussed in terms of the potential processes guiding the relation between attention and cognitive outcome and the development of endogenous control of attention.

Infants flexibly use different dimensions to categorize objects.

A sequential-touching task was used to investigate whether 14-month-old infants can rapidly change how they categorize a set of objects, recognizing new groupings of objects they had previously categorized in a different way. When presented with a collection of objects that could be categorized by shape (balls vs. blocks) or material (soft vs. hard), infants who showed stable performance on a superordinate-level categorization task or who had larger receptive vocabularies exhibited flexible categorization; they categorized the objects by material as well as by shape. Infants who rarely responded to the superordinate-level categorization task or who had smaller receptive vocabularies, in contrast, categorized primarily by shape. Thus, flexible categorization is related to development in other cognitive domains.

Infants Can Rapidly Form New Categorical Representations

Young infants learn common categorical distinctions, such asanimals versusvehicles. But can they, like adults, rapidly form new categories, such asblack-and-white animals? To answer this question, 6-, 10-, and 13-month-old infants were familiarized with four land animals that were black and white in coloring (e.g., a zebra and a black-and-white tiger) and then were tested with novel animals and a truck. The infants responded to an exclusive category that apparently included only black-and-white animals, suggesting that they formed a new categorical representation during familiarization. A comparison group of infants familiarized with a set of land animals that were more variable in coloring (e.g., a pale yellow horse and a yellow-and-brown tiger) formed a very general categorical representation that included many different kinds of animals, regardless of coloring. Therefore, like adults, infants rapidly form new categorical representations in response to the context.

Developmental changes in visual short-term memory in infancy: evidence from eye-tracking

We assessed visual short-term memory (VSTM) for color in 6- and 8-month-old infants (n = 76) using a one-shot change detection task. In this task, a sample array of two colored squares was visible for 517 ms, followed by a 317-ms retention period and then a 3000-ms test array consisting of one unchanged item and one item in a new color. We tracked gaze at 60 Hz while infants looked at the changed and unchanged items during test. When the two sample items were different colors (Experiment 1), 8-month-old infants exhibited a preference for the changed item, indicating memory for the colors, but 6-month-olds exhibited no evidence of memory. When the two sample items were the same color and did not need to be encoded as separate objects (Experiment 2), 6-month-old infants demonstrated memory. These results show that infants can encode information in VSTM in a single, brief exposure that simulates the timing of a single fixation period in natural scene viewing, and they reveal rapid developmental changes between 6 and 8 months in the ability to store individuated items in VSTM.