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.     

Psychophysiological evidence for continuous information transmission between visual search and response processes.

This study was designed to test whether information transmission between the perceptual and motor levels occurs continuously or in discrete steps. Ss performed visual search across nontargets that shared visual features with one of two possible targets, each assigned to a different response. In addition to reaction time, psychophysiological measures were used to assess the duration of target search and the onset of central and peripheral motor activity. Nontargets sharing features with a target selectively activated the response associated with that target, even when it was not present in the display. This suggests that information transmission to the motor level can consist of fine-grained visual information and that visual search and response selection occur in parallel.