Hand-movement profiles in a tactual—tactual matching task: Effects of spatial factors and laterality

We examined the effect of spatial factors and hemispheric lateralization upon hand-scanning strategies in 14 right-handed men tested in a tactual—tactual matching task. The experiment involved comparisons (judgments of same or different) between two objects sequentially touched by the fingertips of the left or right hand. Stimuli were made of smoothly joined cubes whose junctions were not haptically discernible. Exploratory strategies were inferred from the durations and locations of hand contacts with any of the cubes composing the stimuli. Accuracy was greater when the same stimulus was touched twice by the same hand than when different hands were used to feel it. With regard to strategies, both hands touched the upper parts of the object longer than the lower parts. Subjects also inspected more portions of the objects ipsilateral to the hand used. Overall differences in time spent touching cubes were greater for the right hand than for the left hand, showing that touch times were less evenly distributed on object parts for the former than for the latter. In this study, the process of information gathering by touch appears to be determined by the intertwining integration of contextual factors (e.g., stimulus position in space), biomechanical constraints on hand movements, and such cognitive factors as hemispheric differences on the ability to encode spatial pattern information.     

On the facilitatory effects of cognate words in bilingual speech production

There is a growing body of evidence showing that a word's cognate status is an important dimension affecting the naming performance of bilingual speakers. In a recent article, Kohnert extended this observation to the naming performance of an aphasic bilingual (DJ). DJ named pictures with cognate names more accurately than pictures with non-cognate names. Furthermore, having named the pictures in Spanish helped the subsequent retrieval (with a delay of one week between the two tests) of the same pictures' names in English, but only for pictures with cognate names. That is, there was a language transfer but only for those translation words that were phonologically similar. In this article we first evaluate the conclusions drawn from these results by Kohnert, and second we discuss the theoretical implications of the facilitatory effects of cognate words for models of speech production in bilingual speakers.     

Outcome additivity and outcome maximality influence cue competition in human causal learning

Recent research suggests that outcome additivity pretraining modulates blocking in human causal learning. However, the existing evidence confounds outcome additivity and outcome maximality. Here the authors present evidence for the influence of presenting information about outcome maximality (Experiment 1) and outcome additivity (Experiment 2) on subsequent forward blocking. The results of Experiment 3 confirm that, with outcome maximality controlled, outcome additivity affects backward blocking but not release from overshadowing. Finally, the results of Experiment 4 demonstrate that information about outcome additivity has a similar effect on forward blocking if presented after the blocking training instead of before. The results are compatible with the idea that blocking results from inferential processes at the time of testing and not from a failure to acquire associative strength during training.     

Categorizing facial identities, emotions, and genders: attention to high- and low-spatial frequencies by children and adults

Three age groups of participants (5-6 years, 7-8 years, adults) matched faces on the basis of facial identity. The procedure involved either low- or high-pass filtered faces or hybrid faces composed from two faces associated with different spatial bandwidths. The comparison stimuli were unfiltered faces. In the three age groups, the data indicated a significant bias for processing of low-pass information in priority. In a second task, participants were asked to identify the emotion (smiling or grimacing) or gender (male or female) of hybrid high-pass/low-pass faces. Opposite results emerged in the two tasks irrespective of the age group; the gender discrimination task indicated a bias for low-pass information, and the emotion task indicated a bias for high-pass information. These differences suggest independent processing routes for functionally different types of information such as emotion, gender, and identity. These routes are already established by 5 years of age.     

Activation of adenosine receptors in the posterior cingulate cortex impairs memory retrieval in the rat

Adenosine A1 and A2A receptor agonists and antagonists have been reported to alter learning and memory. The aim of our study was to investigate the involvement of adenosinergic system in memory retrieval into posterior cingulate cortex (PCC) of Wistar rats. To clarify this question, we tested specifics agonist and antagonists of adenosine A1 and A2A receptors in rats submitted to a one-trial inhibitory avoidance task. The stimulation of adenosine A1 and A2A receptors by CPA and CGS21680, respectively, impaired memory retrieval for inhibitory avoidance task, into PCC. These findings provide behavioral evidence for the role of adenosinergic system in the memory retrieval into PCC.     

Assessment Centre Observation Procedures: An Experimental Comparison of Traditional,Checklist and Coding Methods

Concern about the construct validity of assessment centre judgements has led to calls for research into observers’ cognitive processes. In an experiment comparing the Traditional observation procedure against use of a Behavioural Checklist and of Behavioural Coding, six outcome variables were examined. The methods were found to yield similar outcomes in terms of accuracy of judgement, accuracy of written evidence, correlation between dimension ratings, and attitude toward the method employed. However, significant between-method differences were observed in variability between observers and in their willingness to recommend a procedure. It is argued that Behavioural Coding has special merit in assessment centres; the method reduces the cognitive demands placed on assessors, and valuably structures their information-processing. Traditional objections to simultaneous observation and classification are shown to be inappropriate.     

MODIFICATION OF ACTIVITY LEVEL THROUGH BIOFEEDBACK AND OPERANT CONDITIONING1

The biomotometer, an electronic device that simultaneously measures activity and provides auditory feedback to the subject, was used in combination with material reinforcers in two experiments attempting to modify activity level in children. In the first study the activity level of an 11-year-old highly active boy was decreased below mean baseline during conditioning in a classroom setting. His level of activity returned to baseline when feedback was withdrawn. In the second study, activity level of a 10-year-old hypoactive boy was increased over mean baseline level during conditioning in a free-play setting, and returned to slightly below baseline during five extinction trials. Results of these studies indicate that the biomotometer is a useful instrument for modification of activity level.     

Activity level: A comparison between actometer scores and observer ratings

Activity level of 13 boys (aged 9–13) from a day hospital program was measured using actometers in classroom, gym, woodshop, and group therapy settings. Ratings of Ss' activity were obtained from mothers using the Werry scale, and from six clinical staff familiar with the Ss using the Davids scale. It was predicted that activity ratings would have situationally specific relationships with actometermeasured activity level according to the rater's opportunities for observation. Comparisons between measures indicated that all clinical staff ratings correlated significantly with actometer activity in the classroom (r=.49 to r=.73), while mothers' ratings correlated significantly with actometer activity in gym (r=.67), and woodshop (r=.77), and with overall activity (r=.65), a combined measure derived from actometer scores in the four conditions tested. Five of six clinical staff raters showed significant interrater reliability (r=.58 to r=.83). Results are discussed in terms of their implications for solution of current problems in assessment of activity level and hyperactivity.