Sharing behavior and racial preference in children

Three groups of white children, 43 preschoolers and first-graders, 46 third-graders, and 44 fifth-graders, were asked to choose either a white child or a black child as a recipient of sharing and also as a companion for several social interaction situations ordered for social distance. The preschoolers and first-graders preferred to share and interact socially with the white child. The third-graders and the fifth-graders displayed a weaker preference for the white child over the black child on the sharing task, no preference in situations of high social distance, and a preference for the white child in situations of low social distance. The results from ancillary measures suggested that the choices of the younger children were motivated by a generalized color preference but that the choices of the older children were guided by an awareness of the social meaning of racial categories.The investigation was supported by the Research Advisory Council of East Tennessee State University.     

Syntactic effects in sentence completion by Broca's aphasics

A study of six Broca's aphasics is reported. The task was to complete sentence frames with a missing word whose type was systematically varied by syntactic form class (nouns, verbs, prepositions, and particles) and the number of lexical options appropriate to any given instance. The primary aim was to contrast syntactic type (content vs. function words) and level of sentential constraint as ways of determining whether there was a central syntactic component to the language deficit. There was a significant effect for word type and an interaction between word type and level of constraint. These results are discussed as supporting a syntactic interpretation of the deficit.     

How a thing is called—A study of mothers' and children's naming

Mothers' selections of category names in object-naming tasks were examined using the levels of categorization defined by Eleanor Rosch (E. Rosch. In T. Moore (Ed.), Cognitive development and the acquisition of language, New York: Academic Press, 1973. E. Rosch. In E. Rosch & B. Lloyd (Eds.), Cognition and categorization. Hillsdale, N.J.: Erlbaum, 1978. E. Rosch, C. Mervis, W. Gray, D. Johnson, & P. Boyes-Braem. Cognitive Psychology, 1976, 8, 382–439). The effect of three variables—Presentation Context, Taxonomy, and Age (of person for whom mother was naming the items)—on mothers' choice of category names, was also investigated. The stimuli were 36 photographs of common concrete objects representative of four taxonomies. Forty mothers named the stimulus items for their 2-year-olds (N = 20), for their 4-year-olds (N = 20), and for the Experimenter. The category labels that children of both ages used when naming the same items, and mothers' independent predictions of the names their children would use in the naming task, were recorded. Contextual factors were found to have a primary role in determining mothers' selections of category names and the three independent variables had a complex and dynamic effect on mothers' naming practices.     

Discrimination and generalization by rats of temporal stimuli lasting for minutes

In three experiments, rats learned to respond differentially to reinforced and nonreinforced trials when the length of the intertrial interval (ITI) predicted the trial outcome (reinforcement or nonreinforcement). Rats in control groups, for whom the length of the ITI did not predict the outcome, did not show differential performance on nonreinforced and reinforced trials. Generalization gradients obtained following discrimination training were comparable to those obtained following discrimination training with other types of discriminative stimuli. That is, groups which had shown differential performance in discrimination training yielded generalization gradients with fastest speeds at the previously reinforced ITIs, slowest speeds at the previously nonreinforced ITIs, and intermediate speeds at ITIs of intermediate length. Control groups yielded flat gradients across all ITIs tested. These effects were shown for relative time discrimination (short time = reinforcement, long time = nonreinforcement, or the reverse) and also for an absolute time discrimination (long and short time = reinforcement, middle time = nonreinforcement or the reverse). This method was effective for time duration measured in minutes rather than seconds, as is more commonly the case.     

A low-stress restraint procedure for EEG acquisition in awake rats

A restraint procedure was developed to reduce movement-related artifacts during the acquisition of EEG data from unanesthetized, unparalyzed rats. It combines the low-stress properties of a cloth restraint bag with the improved immobility of a rigid restraint device. The spontaneous behavior of the rat facilitates both the induction of and the subsequent release from restraint.     

The PSYCHLAB programming system: A tool for developing experimental control programs

The PSYCHLAB system is designed to facilitate the task of writing experimental control programs. The system consists of two major components: (1) a collection of procedures and functions to facilitate presenting stimuli, collecting responses, and measuring response times and (2) a high-level language (LAB-TALK) designed to organize and sequence events in experiments. The PSYCHLAB system is formally an interpreter that will interpret programs written in LAB-TALK. The interpreter is customized to perform the detailed functions of each trial in an experiment. The occurrence of these trials is controlled by the LAB-TALK program. Thus, once a particular experimental paradigm has been represented in a customized version of the interpreter, many different experiments in that paradigm can be programmed by variations in the LAB-TALK program.     

Selective attention to multidimensional auditory stimuli

Event-related brain potentials (ERPs) elicited by multidimensional auditory stimuli were recorded from the scalp in a selective-attention task. Subjects listened to tone pips varying orthogonally between two levels each of pitch, location, and duration and responded to longer duration target stimuli having specific values of pitch and location. The discriminability of the pitch and location attributes was varied between groups. By examining the ERPs to tones that shared pitch and/or locational cues with the designated target, we inferred interrelationships among the processing of these attributes. In all groups, stimuli that failed to match the target tone in an easily discriminable cue elicited only transitory ERP signs of selective processing. Tones sharing the "easy" but not the "hard" cue with the target elicited ERPs that indicated more extensive processing, but not as extensive as stimuli sharing both cues. In addition, reaction times and ERP latencies to the designated targets were not influenced by variations in the discriminability of pitch and location. This pattern of results is consistent with parallel, self-terminating models and holistic models of processing and contradicts models specifying either serial or exhaustive parallel processing of these dimensions. Both the parallel, self-terminating models and the holistic models provide a generalized mechanism for hierarchical stimulus selections that achieve an economy of processing, an underlying goal of classic, multiple-stage theories of selective attention.     

Social influence processes affecting adolescent substance use

Social influence is central to models of adolescent substance use. Nonetheless, researchers fail to delineate the various forms of social influence. A framework that distinguishes between active (explicit drug offers) and passive (social modeling and overestimation of friends' use) social pressure was tested. The effect of these processes on alcohol and cigarette use was examined with 526 seventh graders taking part in an alcohol prevention program. Hierarchical regression analyses demonstrated that pretest measures of alcohol use, offers, modeling, and overestimation each accounted for unique variance in posttest alcohol use. Similar results were obtained for cigarette smoking. The general model was not significantly different for boys and girls, or for prior users and prior nonusers, supporting the generalizability of the framework. Implications for intervention programs are discussed.