Vibrotactual choice reaction time,tactile receptor systems and ideomotor compatibility

In most of the literature on human performance the results of an experiment by Leonard (1959) are quoted as the most outstanding example of perfect S-R-compatibility. In that experiment the fingertips were stimulated by a 50 Hz vibration; the vibrating armature had to be depressed and the reaction times of the right index finger were recorded. The reaction time was found not to increase with an increasing number of tactual choices. In experiment 1 of the present study, also applying 50 Hz vibrations, the reaction times of other fingers were also reported. In addition the response stimulus interval (RSI) was varied. Leonard's results were not replicated: reaction time increased with the number of tactual choices at all levels of RSI. In experiment 2 the frequency and amplitude of vibration were systematically varied and it turned out that these variables could account for the differences between the results found. An increase in reaction time with the number of tactual choices was found with weak vibrations, but not with strong vibrations. The differences in reaction time patterns appeared to be caused by differences in tactile receptor systems (i.e. the non-Pacini versus the Pacinian system). It was concluded that the concept of S-R-compatibility did not cover the pattern of results but that the concept of ideomotor compatibility did.     

Extinction of the context and latent inhibition

The hypothesis that latent inhibition could be reduced by extinguishing the experimental context, that is, exposing the rats to the context between exposure to the conditional stimulus (CS) and conditioning, was tested. All experiments used the conditioned emotional response procedure. In Experiment 1, extinction was not effective when the animals were exposed to the clicker 40 times off the baseline of responding for food and when the clicker CS was partially reinforced with shocks during the test phase. In Experiments 2 and 3, latent inhibition could be reduced by extinction if the animals were exposed to the CS 24 or 16 times on-baseline, and if continuous reinforcement was used during the test. In Experiments 4, 5, and 6, we attempted to determine which variable was responsible for the discrepant results. In Experiment 4, extinction was effective with 20 or 40 on-baseline exposures to the CS, using continuous reinforcement during the test. In Experiment 5, extinction was not effective with exposure on- or off-baseline, using 24 exposures and partial reinforcement. Finally, in Experiment 6, extinction reduced latent inhibition using continuous, but not partial, reinforcement with 40 exposures off-baseline. From these results, we concluded that Wagner's model of habituation was not sufficient to account for latent inhibition and that a hybrid model, using both associative and cognitive representational processes, was necessary.     

Conditioning of counter-empathetic emotional responses

The present research tested the hypothesis that the quality of an observer's vicarious emotional response, as measured by autonomic, expressive, and self-report indexes, is a function of the observer's conditioning history with particular facial expressive displays of emotion. It was predicted that conditions of congruence (Symmetry) between the affective expression of a model and the outcome (shock or reward) presented to an observer would enhance initial empathetic responses, but that conditions of incongruence (Asymmetry) between the model's displays and observer's outcomes would lead to counter-empathetic responses. These changes in the quality of observers' vicarious emotional responses should generalize to a test phase when no rewards or punishments are presented to observers. The results for all measures were consistent and indicate that asymmetric conditioning modified the initial empathetic responses of observers to either counter-empathetic responses or indifference. On the other hand, symmetric conditioning enhanced observers' initial empathetic responses. These effects were evident in the test phase when no reinforcements were administered to the subject. The results are consistent with the theoretical assumption that facial expressions of emotion can acquire meaning and hedonic valence because of their predictive significance and thus can function as conditioned stimuli capable of evoking empathetic and counter-empathetic emotional responses.     

Attribution and reconstructive memory

Two experiments were conducted to test the effects of making an attribution on later memory for the event that gave rise to the attribution. Subjects in Experiment 1 observed a scenario in which an actor's behavior was associated with high or low variance (distinctiveness) across situations, and high or low congruence (consensus) to the actions of others. Subjects either made attributions for the actor's behavior immediately following the scenario or not. One week later, subjects were asked to recall consensus and distinctiveness for the actor's original behavior. Subjects who made attributions were significantly better at estimating the high-high and low-low combinations of consensus and distinctiveness than were their no-attribution counterparts. It was suggested that making an attribution may allow for a reconstructed memory for the original event, but not enhance direct access to the original event information. A second experiment tested this concept further by having subjects view an edited version of the scenario in which either the distinctiveness or the consensus information was deleted and having subjects make attributions or not. One week later, subjects were asked to indicate their certainty that consensus and distinctiveness information was a part of the original scenario and to estimate the levels of consensus and distinctiveness. Subjects who made attributions were more confident and accurate in estimating the level of consensus or distinctiveness that was given in the original scenario than were no-attribution subjects. However, attribution subjects were also more confident that consensus information or distinctiveness information was contained in the scenario (when it was not) than were the noattributio subjects. Results of the two experiments suggest that eliciting attributions can distort subsequent memory for the event on which the attributions were based.     

The development of alertness

Two experiments explored variation in the alerting process across age and warning interval as well as the effects of alertness on subsequent processing. Experiment 1 obtained alertness functions for a group of 5-year-olds, 8-year-olds, and adults. Results revealed strong age differences in speed of alerting and in maintenance of alertness over a 1-sec interval. Five-year-olds alerted more slowly than older groups and sustained optimal alertness less well. Both groups of children showed more variability in alerting functions compared with adults. Experiment 2 examined the degree to which age differences in processing speed were attributable to differential speed and maintenance of alerting. Masking functions obtained across variations in the alerting interval revealed that when level of alertness was optimal in both 5-year-olds and adults, minimal age differences in processing speed were observed. During short, nonoptimal alerting intervals, speed of processing in adults was faster than in 5-year-old children. The pattern of results across studies suggested that alertness can fluctuate over time in young children, that level of alertness affects subsequent perceptual processing speed, and that developmental variation in speed and maintenance of alertness can partly explain observed age differences in processing speed. The potential role of alertness in more complex cognitive tasks is discussed.     

The development of spatial understanding in infancy

This paper examines the development of spatial understanding between 8 and 24 months. In particular, it examines whether young infants code changes in the position of an object or themselves in geographic or egocentric terms. The infants sat in a baby chair which was attached to a circular table in such a way that either the infant could be rotated around the edge of the table or the table-top itself could be rotated. Rotation of infant or table could be performed independently or simultaneously. Infants were shown an object which was then hidden under one of either two or three identical cups sitting on the table. Before the infant was allowed to search for the toy, either the table, the infant, or both were rotated, a procedure which resulted in an invisible displacement of the object in terms of geographical and/or egocentric spatial position. Rotations of 60, 90, 120, and 180° were used. Three groups of infants were tested, one cross-sectional (12–24 months), one longitudinal (12–24 months), and one consisting of a group of infants already known to be accelerated in object concept development (8–20 months). The cross-sectional results indicated that egocentric responding continues well into the second half of the second year of life. Even with fortnightly exposure to the tasks, egocentric responding was still evident in some longitudinal babies as late as 19 months. The results of the accelerated group suggest that acceleration through the sequence of object concept development facilitates development of spatial understanding in a wider sense, that is, in the sense of understanding the interrelation of positions in space. The implications of these results for competing theories of the source of object concept errors are discussed.     

Communicative gestures of the hand and arm when 4-year-old sons and their mothers interact

This study investigated a wide range of communicative hand/arm gestures of 4-year-old males when interacting with their mothers. The types of gesture categories observed were in keeping with the predicted encoding ability of this aged child. Pantomimic and deictic gestures were observed in significantly greater numbers than semantic modifying and relational gestures. Although it was found that the mothers' gestural usage reflected the type of gesture categories seen in the children's group, no correlation was found between gesture usage of individual mother-child pairs.     

Alternate antagonism with paradoxical translation behavior in two bilingual aphasic patients

Two patients presenting a pattern of recovery yet unreported in the literature were observed, one in Paris, the other in Montreal. Both patients alternately suffered severe word-finding difficulties in one language while remaining relatively fluent in the other. They retained good comprehension in both of their languages at all times. They were able to translate correctly and without hesitation from the language they could speak well at the time into the language unavailable for spontaneous use, but were unable to translate from their temporarily poor language (which they understood well) into the language which they could speak quite well at the time.