Laraine McDonough

Concept Formation in Infancy.

Four experiments investigated conceptual categorization in 7- to 11-month-old infants. Experiments 1 and 2 showed that 9-and 11-month-olds differentiated the global domains of animals and vehicles. Within the animal domain no subcategorization was found: the infants did not differentiate dogs from fish or from rabbits. Within the vehicle domain infants differentiated cars from both airplanes and motorcycles. Experiment 3 showed similar, although weaker, categorization for 7-month-olds. Experiment 4 showed that categorization of animals and vehicles was unaffected by degree of between-category similarity. Birds and airplanes were treated as different even though the exemplars from both categories had similar shapes, including outstretched wings, and were of the same texture. These data, showing global differentiation of animals and vehicles, with lack of differentiation of “basic-level” categories within the animal domain, contrast with data from studies designed to assess perceptual categorization. Even younger infants differentiate various animal subcategories perceptually. However, the results presented here suggest that infants may not respond to such perceptual differences as being conceptually relevant.

Separating the sheep from the goats: Differentiating global categories ☆

Abstract The nature of the conceptual categories that children have developed in the second year was studied in a series of experiments using an object-manipulation task. In the first two experiments, it was shown that by 18 months children have developed global conceptual categories of animals and vehicles without yet clearly differentiating basic-level categories within these domains. The basic-level categories were tested by using a series of contrasts: a low degree of contrast was provided by presenting the children with dogs versus horses and with cars versus trucks. A moderate degree of contrast consisted of dogs versus rabbits and cars versus motorcycles. A high degree of contrast consisted of dogs versus fish (or birds) and cars versus airplanes. A domain-level contrast of animals versus vehicles was included as well. From 18 to 30 months the children tended to respond categorically only on the global domain-level contrast and on the high-contrast basic-level distinctions. Not until 30 months did the children consistently differentiate the low and moderate basic-level contrasts. Experiment 3 replicated the finding of global animal and vehicle categories, using the widest possible range of exemplars. Experiment 4 extended the study of global categorization to the domains of plants, furniture, kitchen utensils, tools, and musical instruments. Global categorization was found for plants, furniture, and kitchen utensils, but not for tools and musical instruments. Experiment 5 found little evidence for basic-level categorization of plants, and only suggestive evidence for basic-level categorization in the domains of furniture and utensils. The data demonstrate the presence of a number of global conceptual categories from an early age, and suggest that at least in some domains (animals, vehicles, and plants) such categories develop before true basic-level distinctions are made.

Early Sensitivity to Language-Specific Spatial Categories in English and Korean

This study investigates young childrens comprehension of spatial terms in two languages that categorize space strikingly differently. English makes a distinction between actions resulting in containment (put in) versus support or surface attachment (put on), while Korean makes a cross-cutting distinction between tight-fit relations (kkita) versus loose-fit or other contact relations (various verbs). In particular, the Korean verb kkita refers to actions resulting in a tight-fit relation regardless of containment or support. In a preferential looking study we assessed the comprehension of in by 20 English learners and kkita by 10 Korean learners, all between 18 and 23 months. The children viewed pairs of scenes while listening to sentences with and without the target word. The target word led children to gaze at different and language-appropriate aspects of the scenes. We conclude that children are sensitive to language-specific spatial categories by 18–23 months.

Inductive generalization in 9‐ and 11‐month‐olds

Using little models, we showed 9- and 11-month-old infants events in which animal or vehicle properties were demonstrated, such as a dog drinking from a cup or a car giving a ride. The infants were tested on imitation of these properties on the same exemplars as used for the modeling, on generalization to other exemplars from the same domain, and on generalization to exemplars from an inappropriate domain. Infants generalized the properties broadly to both typical and novel exemplars within the appropriate domain, and rarely to exemplars from the inappropriate domain. It is concluded that at least by 9 months infants have formed global concepts of animals and vehicles that control the way infants learn the characteristic properties of these classes.

Deficits, delays, and distractions: an evaluation of symbolic play and memory in children with autism.

Two experiments were conducted to evaluate symbolic-deficit and memory-deficit hypotheses to account for the cognitive problems seen in children with autism. Experiment 1 tested imitation, in immediate and deferred conditions, of familiar actions with different sets of objects representing the developmental progression from functional to symbolic play. The results showed that the autism group and both their receptive language and nonverbal IQ-matched controls imitated familiar actions with realistic objects (evidence for functional play) and placeholder objects (evidence for symbolic play) after delays ranging from 24 hr to 3 weeks. Experiment 2 tested familiar three-step event sequences in which a placeholder object was substituted for the second step in half the events. The results showed that the autism group remembered as many of the actions with the placeholder objects as their language-matched controls and as many correctly ordered sequences, a finding that supports a symbolic-delay (rather than deficit) hypothesis. These results were obtained in highly structured test situations and sharply contrast with the impairments seen in children with autism who are observed in naturalistic settings. Two interpretations of these findings are offered. First, structured test settings minimize distractions that typically occur in naturalistic settings that may interfere or disrupt symbolic play in children with autism. Second, the results are consistent with an executive function deficit in that the autistic group demonstrated more knowledge in the test settings than they demonstrate spontaneously in naturalistic ones.

Advancing Downward to the Basic Level

In 3 experiments, we studied whether infants and young children understand various basic-level conceptual distinctions in the domains of household artifacts, animals, and vehicles. Using small replicas, we modeled events such as washing dishes in a sink for children 14, 19, and 24 months old, and then gave them an exemplar from the same basic-level concept (another sink) and an exemplar of another concept from the same domain (bathtub). We measured which object they used to imitate the event. Fourteen-month-olds did not differentiate among basic-level categories in any of these domains, for example, washing dishes in both a tub and a sink, and putting both a rabbit and a bird in a nest. By 19 months, inappropriate behavior was greatly reduced for household artifacts and for vehicles, but not for animals. By 24 months, performance was mainly appropriate for all 3 domains. It was also shown that although 14-month-olds are not making many conceptual distinctions at the basic level, they are nevertheless beginning to make some broader conceptual distinctions among artifacts.

Very Long-term Recall in Infants: Infantile Amnesia Reconsidered

Subjects who had participated in a study on non-verbal recall before their first birthday returned to the laboratory one year later and were tested for recall of their previous visit. During their previous visit they had shown recall of both familiar and novel actions on a set of novel objects. However, after a years delay, evidence for recall was found for the familiar actions only. One action in particular was responsible for this finding: feeding a teddy bear with a schematic bottle. The majority of the returning subjects who had been shown this action repeated it after a year, whereas none of the other returning subjects and few of the subjects in the control groups performed this action. The results indicate that young infants have the ability to recall an event both at 11 months of age and after a delay as long as one year. The finding that infants can recall during a period that later becomes inaccessible to memory is important to our understanding of infantile amnesia.

Higher maternal prenatal cortisol and younger age predict greater infant reactivity to novelty at 4 months: An observation-based study

Distress-linked activation of the maternal hypothalamic-pituitary-adrenal (HPA)-axis is considered a pathway by which affect regulation impacts the fetal milieu and neurodevelopment. There is little direct evidence for this conceptual model. In 103 women [mean age 27.45 (±5.65) years] at 36-38 weeks gestation, salivary cortisol was measured before/after stress tasks; distress questionnaires were completed. At 18.49 (±1.83) weeks, infants underwent the Harvard Infant Behavioral Reactivity Protocol assessing cry/motor responses to novelty; women reported on infant behavior and postnatal distress. Prenatal cortisol and distress were not significantly correlated (all ps > .10). Proportional odds logistic regressions showed that neither prenatal nor postnatal distress was associated with infant responses to the Harvard Protocol yet pre-stress cortisol and maternal age were: The odds of being classified as High Reactive were 1.60 times higher [95% CI: 1.04, 2.46] for each unit of added cortisol and .90 times lower [95% CI: .82, .99] for every additional year in maternal age. No associations were found between cortisol or prenatal distress and mother-rated infant behavior; postnatal distress was positively associated with mother-rated infant negative behavior (p = .03). Observer and mother-rated infant behavior were not associated (all ps > .05). Based on independent observations of infants in contrast to maternal perceptions, these results lend support to the hypothesis that pregnant womens HPA-axis activity influences infant behavior. The impact of maternal distress was not supported, except in so far as postnatal distress may increase the likelihood of making negative judgments about infant behavior.

Image-dependent interaction of imagery and vision

The influence of imagery on perception depends on the content of the mental image. Sixty-three students responded to the location of the 2 hands of a clock while visualizing the correct or an incorrect clock. Reaction time was shorter with valid cueing. Could this have resulted from visual acquisition strategies such as planning visual saccades or shifting covert attention? No. In this study, a crucial control condition made participants look at rather than visualize the cue. Acquisition strategies should have affected equally both types of cueing, but we observed that the effect of the visual cue was smaller and limited to a particular subcase in which one expects visual acquisition strategies. Thus, what matters is the similarity of the content of the mental image with the visual scene. In addition, an interaction involving the hand used for responding supports the notion that composite imagery is lateralized.

The mobile conjugate reinforcement paradigm in a lab setting

The mobile conjugate reinforcement task was administered to 4-month-old infants in a lab rather than a home setting where it is usually administered. Learning and retention patterns were comparable to those of infants tested in their homes, suggesting flexibility in where this task can be administered. These results pave the way for this task to be used with a broader range of infants for whom home visits are not practical or convenient (e.g., infants in child care). Developmental research conducted with a more diverse population of infants would facilitate our understanding of cognitive development very early in life.