Oscillations in retention performance after passive avoidance training

The retention performance of independent groups of rats was examined at various intervals following one-trial passive avoidance training. Performance was good in the 30-sec, 15-min, 12-hr, 24-hr, and 36-hr group, while retention was significantly poorer between these peaks. Control experiments appear to rule out strictly performance factors related to footshock. These results suggest that some rhythmic internal (physiological) state of the organism may be a relevant condition for optimal retrieval—a state-dependent hypothesis.     

Structural consequences of individual position in nondyadic social networks

The pattern of dyadic relationships among members of a population has often been used to obtain important information on the way that social structure can further or constrain social action. More recently, it has been proposed that nondyadic relationships can play a similar role. In this paper, a formalism is proposed that allows the dyadic structure and the nondyadic structure to be considered simultaneously. If this formalism is applied to the study of the structure arising from attendance at significant social events, it becomes possible to identify potential loci for social action. Still further, it is shown that information on individuals' structural perspectives with respect to such potential loci can be translated into conclusions about the individuals' positions in the dyadic structure. Such considerations can be used to evaluate the relative potential of these loci for social action.     

Hemispheric interference: A dual-task investigation of youngsters who stutter

Hemispheric interference was studied in this investigation by requiring 24 right-handed grade-school children who stutter to tap a button, as rapidly as possible, in five randomized conditions. Hand order was counterbalanced in the single-task silent control condition and in the four increasingly demanding dual-task conditions. In three of the experimental conditions tapping and speech occured concurrently. In the fourth dual-task condition the subjects were to vocalize the sound of a siren (in an irregularly patterned way) as they tapped the button. Analysis of the tapping rates in this two-by-five factorial study revealed statistically significant differences among hands and conditions. The tapping rate was faster with the right than with the left hand and the rate decreased as the demands of the dual-task conditions increased. Interaction was not evidenced; the interference pattern was similar in both hands across the conditions. Since interference was significantly present in both the speech and vocalic conditions, the data are not consistent with a laterality model. This finding and the increase in interference with increased attentional demand, however, are consistent with a capacity framework.     

First-grade boys' responses to a new task following noncontingent feedback

Sixty-four first-grade boys trained on a two-choice discrimination task received positive feedback either contingent upon their correct responses or in the same amount but noncontingently. Each child was then asked to choose between two alternate ways of accumulating pennies. He could solve problems and earn pennies for correct responses to a contingent task, or he could collect pennies at the same rate by remaining passive. The purpose of this research was to determine if the usual effects of noncontingent feedback would transfer from a simple training procedure to a different contingent task. It was found that the total amount of time spent at the passive alternative did not differ between training conditions. However, a significantly greater number of noncontingently trained children did choose the passive alternative early during testing; these children either gave all of their time to the passive alternative or, very shortly after attempting the task, switched to the passive response. When the noncontingently trained children did choose to work actively during testing, their performance reflected ineffective problem-solving strategies. These results suggest that even when conditions change, experience with prior noncontingent feedback disrupts the ability to utilize contingent information.     

Novelty responding and behavioral development in young,developmentally delayed children

This study examined whether or not a measure of information processing ability based on the discrimination of novel and familiar stimuli was related to behavioral development among developmentally-delayed infants. Two samples of handicapped infants were administered multiple measures of visual novelty discrimination and a battery of assessments which were representative of available measures of development in infancy. The results indicated that, as a group, the developmentally delayed infants were capable of discriminating novel and familiar stimuli. Also, correlational analyses indicated that responding to novelty was related to developmental accessment performance in both samples. This finding is consistent with previous data which indicates that novelty response measures are associated with important individual differences in young children.     

Some theorems in haploscopic vision

Three formal hypotheses are specified concerning the combination of neural signals from the two eyes. The hypotheses are (1) that a large uniform light presented to the opposite eye has no effect (independence), (2) that all information from one eye relevant to a given percept (for example, brightness) is encoded by a single neural signal (isolation), and (3) the mutually exclusive and exhaustive alternative to isolation (interaction). Though independence or isolation often has been claimed or simply assumed to hold, these hypotheses imply specific empirical relationships. These relationships are derived for brightness and for equilibrium colors. In addition, one model consistent with the interaction hypothesis is developed. The isolation hypothesis is important for generalizing results from monocular experiments to normal binocular vision. If it is false, monocular results can reflect a combination of one eye's neural signals that never occurs with binocular stimuli.     

A mathematical analysis of a natural class of partitions of a graph

Any finite graph (nondirected, no loops) can be coupled with its complementary graph producing what we term a completed graph. This paper studies completed graphs in the context of a structural concept called stratification that is motivated by theoretical work in social psychology and sociology. A completed graph is stratified in case its node (vertex) set can be divided into two nonempty subsets with exactly one of the two types of ties holding between every pair of nodes from distinct sets. A completed graph is totally stratified in case every one of its nontrivial completed subgraphs is stratified. The first part of the paper relates the concept of stratification to the familiar graph property of connectedness. In particular, a completed graph is totally stratified if and only if it does not have a four point completed subgraph that is connected in both the original graph relation and its complementary relation. Using the concept of stratification, completed graphs can be decomposed uniquely into taxonomic structures, that is, nested sets of partitions. An algorithm for the decomposition based on the work with the concept of stratification is developed. The relationship between the notion of stratification and the ideas in balance theory is examined, and stratification is viewed as a generalization of Davis' notion of clustering. It turns out that the concepts of clique, status, and structural equivalence used throughout the social networks literature can be defined in an interesting way for completed graphs. Cliques are sets of nodes with similar internal links and statuses are sets of nodes with similar external links. Structurally equivalent sets are both cliques and statuses. The concepts of status and structural equivalence are closely related to the decomposition algorithm. In particular, for any totally stratified completed graph, the set of all statuses and the set of all maximal structurally equivalent sets can be generated by mathematical operations performed on the taxonomic decomposition of the completed graph. Finally some of our resuls are informally related to the blockmodeling approach to analyzing social network data discussed in several previous Journal of Mathematical Psychology articles.     

Motivated remembering efforts during tip-of-the-tongue states

Hart (1965) argues that the feeling of knowing in tip-of-the-tongue (TOT) states monitors memory content and motivates retreival efforts. Although a number of studies have examined the memory-monitoring accuracy of feelings of knowing and not-knowing, no studies have focused directly on the hypothesized motivational function of these feeling states. This second function of memory feeling states is investigated in this study by assessing the degree to which TOT and Don't Know (DK) states interfere with a subject's ability to perform well on a concurrent task. Subjects studied a list of arbitrary word pairs for 3, 5, or 7 seconds and then provided Recall, TOT, or DK reports in an immediate recall test. Performance on the simple number-probe task that followed each memory report was poorer on TOT trials than on DK trials. This effect did not vary as a function of encoding time. Since covert memory searches were possible on both TOT and DK trials, it is concluded that the performance decrement observed on TOT trials is due to the fact that covert TOT target searches command processing capacity that might otherwise go to the concurrent number-probe task. The absence of an encoding time effect suggests that TOT states do not monitor the associative strength of target traces as Hart (1967) has proposed. The findings in this study are interpreted as providing support for the proposition that the feeling of knowing in the TOT state influences the setting of capacity-allocation priorities in the memory system.     

Voice onset time in aphasia: Thai. I. Perception

This study investigated left brain-damaged aphasic and right brain-damaged non-aphasic patients' ability to label synthetic speech continua differing in voice onset time (VOT) at three places of articulation. The language chosen for investigation was Thai, which exhibits 3 contrasting labial and apical stop categories (voiced, voiceless unaspirated, voiceless aspirated) and 2 contrasting velar stop categories (voiceless unaspirated, voiceless aspirated). Results of the labelling task indicated an impairment in VOT perception at all three places of articulation across clinical types of aphasia. Normal performance by the right brain-damaged patient indicated that deficits in VOT perception can be attributed to pathology specific to the language-dominant hemisphere. No relation was found between the aphasic patient's level of auditory language comprehension and his performance on the VOT perception task. It is suggested that the aphasics' impairment reflects a deficit in phonological processing at the linguistic level.