Infant responses of ocular fixation to moving visual stimuli

Infants of 1, 2, and 3 months of age were presented with two checkerboard patterns, one stationary and the other moving in a horizontal oscillatory motion at one of eight rates. An observer who could see only the infant's head and eyes recorded, for each 30-sec trial, (a) the position of first fixation, (b) position of fixation at the end of each 5-sec interval, and (c) a final forced-choice judgment of the position of the moving stimulus. Results showed reliable differences in ocular behavior as a function of rate of stimulus motion for all three groups of infants.     

Speech prosody in Broca's aphasia

Because speech prosody is thought to be impaired in Broca's aphasia, we conducted three experiments using Broca's aphasics and nonneurological control subjects in order to determine to what extent this statement is accurate. Using three acoustic measures of speech prosody—sentence-final fundamental frequency (F₀) fall, F₀ declination, and sentence-final lengthening—we found that some aspects of prosody were spared while others were abnormal. All Broca's aphasics, regardless of degree of impairment, exhibited sentence-final F₀ fall. F₀ declination was present in simple sentences but was absent over longer domains; moreover, the amount of declination was correlated with the degree of linguistic impairment. Sentence-final lengthening was clearly absent in Broca's aphasia; in fact, sentence-terminal words were actually shorter than their sentence-initial and medial counterparts.     

Categorical and schematic organization and the development of retrieval strategies

This study investigated the effects of schematic and categorical organization on young children's recall. Preschool and kindergarten children recalled either a taxonomic list or a story in one of two presentation conditions: an alternate condition, in which the material was presented, children recalled it and the procedure was repeated, or a successive condition in which the material was presented twice and children recalled it twice. Although preschool children's story recall was well organized, their list recall was poorly organized, and organization did not increase over recall trials in either presentation condition. In contrast, kindergarten children's recall of both the story and the list was well organized, and their recall was better organized on the second recall trial than on the first in both presentation conditions. These results are discussed in terms of the development of retrieval strategies during the preschool years/     

Predicting state anxiety: A comparison of multidimensional and unidimensional trait approaches

Endler has proposed that trait anxiety is multidimensional, with individual differences varying across several dimensions of stressing situations. Despite empirical support for the independence of some dimensions, some researchers have employed a single score on a multidimensional measure of trait anxiety, summed from the dimension scale scores, as a singular measure of generalized trait anxiety. This violates the theoretical underpinnings of the approach. This study examined whether a total score on a multidimensional measure of trait anxiety could supplement the ability of individual dimension scale scores in predicting state anxiety responses to dimension-congruent stress. Thirty-two female college students who scored at differing levels of dimensional and general anxiety were required to perform two laboratory stress tasks under conditions of stress representing different dimensions of trait anxiety. The results provide support for a multidimensional approach to general trait anxiety but indicate some value of a total score in supplementing predictions based on individual scale scores. The data provide a cautionary note that a total score on a multidimensional measure is of little value unless full consideration is given to the profile of dimension scale scores.     

Sequencing strategies in children 18–24 months: Limitations imposed by task complexity

Researchers have generally reported that very young children lack the orderly, sequential approach to tasks that characterizes skilled action. This study questions that assumption by investigating to what extent deficits in sequencing are a function of task complexity (type and number of elements), and to what extent sequencing ability is tied to competent task performance. Three tasks—the Lock Box, Pegboards, and Object Grouping—were each presented in two forms, varying only in number of elements. Participants were 38 children between 18 and 24 months of age. The Denver Developmental Screening Test was also administered to all children. When number of task elements increased, there was a dramatic decrease in orderliness of approach. Type of task served to exaggerate or minimize these effects. However, irrespective of task complexity, children used a consistent pattern of organization, generally two or three sequential movements. This strategy, though serving well for tasks of limited dimensions, was inadequate for tasks with more than four or five elements. Sequencing skills, as well as other aspects of performance, were significantly correlated with Denver scores. Results suggest that exceeding the limits of young children's organizing abilities may obscure actual capacities. The role of task complexity in the performance of young children is discussed as it relates to developmental processes, clinical assessment, and teaching.     

The effects of differential reinforcement on generalized imitation

The present study examines the transfer of imitative learning to other nonimitative performance conditions and compares imitative and nonimitative performance under contingencies of differential reinforcement for S⁰ behavior, differential reinforcement for nonimitative behavior, and extinction. Many authors have suggested that a child's continued imitative performance of rewarded S^D and unrewarded S^Δ behavior is a function of subtle social cues or experimental demand present in most generalized imitation procedures. The two experiments presented here support that conclusion but also provide evidence that conclusions drawn from such generalized imitation studies were generally accurate. Even though a child's trial-by-trial imitative performance appeared to be a function of procedural artifacts, the child's later performance in the role of a model indicated that a functionally interdependent generalized response class of imitative behavior had been learned while the child imitated. As such, these experiments generally supported Baer's secondary reinforcement hypothesis for imitative performance and suggest that future research employ nonimitative tasks such as reversed imitation as a measure of imitative learning.     

The effect of a commercial game on children's block design scores on the WISC-R IQ test

Two experiments investigated the extent to which 10-year old children's scores on the WISC-R Block Design subtest were affected by prior experience with a specific commercial game that involved blocks and matching patterns. Experiment 1 found that 12 10-year old children who happened to have experience with the particular commercial game scored approximately three scaled score points higher on the WISC-R Block Design subtest than 24 matched children without game experience. In Experiment 2, 24 children who did not have prior experience with this particular commercial game were randomly assigned either to a Game condition (involving two 15-minute sessions with the game) or to a No-Game condition (which involved no further game experience). Children in the Game condition subsequently increased their WISC-R Block Design scores more than children in the No-Game condition. Taken together, the experiments indicate that relatively brief interactions with a commercial game can cause a significant improvement in children's performance on an IQ subtest.