Linda P. Acredolo

Impact of Symbolic Gesturing on Early Language Development

The purpose of the present study was to evaluate the effect on verbal language development of purposefully encouraging hearing infants to use simple gestures as symbols for objects, requests, and conditions. To this end, 103, 11-month-old infants were divided into three groups, all of whom were seen in the laboratory for a variety of assessments, including standardized language tests at 15, 19, 24, 30, and 36 months. Parents of those in the Sign Training group modeled symbolic gestures and encouraged their infants to use them. Parents of infants in the Non-intervention Control group knew nothing about symbolic gestures or our special interest in language development. As a control for “training effects” (i.e., effects attributable to families being engaged in a language intervention program), parents of a second control group of infants (the Verbal Training group) were asked to make special efforts to model verbal labels. After comparisons of the two control groups minimized concerns about training effects, comparisons between the Sign Training and the Non-intervention Control group indicated an advantage for the Sign Training group on the vast majority of language acquisition measures. These results provide strong evidence that symbolic gesturing does not hamper verbal development and may even facilitate it. A variety of possible explanations for such an effect are discussed.

The role of self-produced movement and visual tracking in infant spatial orientation

In two longitudinal studies, infants were trained at 12 and 18 months to find an object hidden in one of two identical wells in a Plexiglas box. On the test trial, normal access was blocked and infants were either guided by their mother or allowed to move on their own to another opening on the opposite side. In Experiment 1 significantly more correct responding occurred after active movement than after passive at 12 months, with correct responding related to high visual tracking. In contrast, at 18 months correct search without tracking predominated among both movement conditions. A difference between the conditions in the position of the mother on the test trial was ruled out as a contributor to performance on the basis of data from Experiment 2. When opaque sides were inserted to prevent tracking in Experiment 3, active movement no longer facilitated correct search at 12 months, thus indicating that the tracking and not the active movement per se was the critical factor.

The Effect of Active versus Passive Exploration on Memory for Spatial Location in Children.

The effect of active exploration upon memory for spatial location of an event was assessed for children at 2 age levels. Each child took a walk through the same unfamiliar hallway in search of a hidden object which he was later asked to relocate. Half the children were accompanied by an adult holding their hand (passive condition), while the other half proceeded on their own with an adult following behind (active condition). An age x condition interaction revealed that active exploration significantly improved performance of the 3- and 4-year-old group while not affecting the performance of the 9- and 10-year-olds. The 3- and 4-year-olds in the active condition, however, were still significantly less accurate than the older children, despite their experience of self-directed exploration. The results are interpreted as supporting the hypothesis that self-directed activity serves to increase attention of preoperational children to relevant topological cues in the environment, whereas concrete operational children, due to their knowledge of projective and Euclidean space, demonstrate increased capacity to efficiently encode spatial information regardless of the mode of exploration.

Symbolic Gesturing in Language Development

The spontaneous development of symbolic gestures in a normal infant of hearing parents is described. From 12.5 to 17.5 months of age, 13 gestures depicting objects, events, and qualities were develope

The role of attentiveness, mobility history, and separation of hiding sites on stage IV search behavior

Abstract The relationship between visual attentiveness, search behavior, and duration of independent mobility was examined for fifty-six 8- to 10-month-old infants presented with three versions of the Stage IV object permanence task. The number and spatial separation of hiding sites was manipulated to explore the role of these factors on visual attention and search performance. In a repeated measures design, perseverative search errors were less likely on both a two- and a six-location task with equally wide separation of the A and B hiding sites than on a two-location task with A and B close together, thus indicating that spatial separation of sites is a more important contributor to successful search than number of hiding sites alone. In addition, visual attentiveness was significantly associated with correct search at B in all three versions of the task. A significant developmental relationship was found between the length of time infants had been independently mobile and visual attentiveness during the hiding procedure. These findings are discussed in terms of the transition to self-produced mobility and expanding spatial experience in the second half of the first year and how visual attentiveness and search performance might improve as a function of such changes.

Effects of hierarchical organization on children's judgments of distance and direction

The impact of the hierarchical organization of a space on judgments of direction and distance was assessed in two studies using two-dimensional models analogous to those used by A. Stevens and P. Coupe (1978, Cognitive Psychology, 10, 422-437). In each study the models contained two stars and were divided into two parts by a curved boundary line. In the Homogeneous condition the stars were located in the same subsection. In the Congruent condition the leftmost star was in the left subsection and the rightmost star was in the right subsection. In the Incongruent condition the rightmost star was in the left subsection and the leftmost star was in the right subsection. In Experiment 1 first graders, third graders, and college students were required to remember the location of the stars. Results indicated that the first and third graders tended to use the relationship between the subsections as a clue to the relationship between the sites within them, thus extending the results of Stevens and Coupe (1978) to children. In Experiment 2 preschoolers, first, and third graders were asked to judge with the materials directly in front of them, which of the two stars was closer to a site located in one of the subsections. Results indicated that the Incongruent condition led to errors among the preschoolers and first graders but not the third graders, thus indicating that these groups tended to judge as closer the site within the same subsection even though it was really farther away. The results of both studies are discussed as indicative of a tendency among young children to impose organization on information encoded in memory and in relation to increases in metric accuracy, decentration, and efficient scanning which enable them to more accurately evaluate when such organization is and is not appropriate. Implications for behavior in large-scale environments are also discussed, with particular reference to the effect of barriers on perceptions of distance and direction.

Spatial Orientation in Special Populations: The Mentally Retarded, the Blind, and the Elderly

The populations described in the preceding three papers--the mentally retarded, the elderly, and the blind--are certainly far removed from the subjects generally chosen for cognitive mapping research. However, as Hans Furth’s description of cognitive development among deaf children aptly demonstrated (Furth, 1966), the study of atypical populations can often provide valuable insights into the nature of a phenomenon by indicating what factors are or are not necessary for its proper functioning. A second benefit stemming from research of the type just reported is of a more practical sort. It is quite possible that by identifying problems these three populations have with spatial orientation we will have gone half the distance toward determining workable solutions. Few would disagree that the quality of life for the blind, elderly, and mentally retarded would be vastly improved by their being better able to move confidently and independently through both familiar and unfamiliar environments.