SIDE EFFECTS OF THERAPEUTIC PUNISHMENT ON ACADEMIC PERFORMANCE AND EYE CONTACT

The effects of therapeutic punishment delivered following inappropriate behavior on the academic responding and eye-to-face contact of 2 persons with developmental handicaps was examined using a counterbalanced alternating treatment design. Each subject was sequentially taught by two therapists each day. While one of the therapists taught the subject, the second therapist stood in close proximity directly behind the subject. During baseline, neither therapist delivered punishment following inappropriate behavior. During the treatment condition, one of the therapists delivered all punishment regardless of whether she was teaching or standing behind the subject. The therapist who delivered all punishment for 1 subject did not deliver any punishment for the other subject. During the last condition, the therapist delivering all punishment was reversed for 1 of the subjects. The results indicated that the task being taught was mastered by each subject only when the therapist delivering punishment was teaching. Data collected also indicated that each subject made more eye-to-face contact when the therapist delivering all punishment was teaching. Although neither therapist had to deliver punishers often, punishment had to be administered less often when the therapist teaching the subject was also the therapist delivering punishment.     

Selective reaching: distracter effects on movement kinematics as a function of target-distracter separation

The authors investigated distracter effects on the kinematics of reaching movements to determine when during reaching responses (reaction time, time to peak velocity, time after peak velocity, or peak velocity) distracter interference occurred and how target-distracter separation affected the locus of interference. Participants moved a pen on a digitizing tablet toward a target appearing with or without a distracter. With a small target-distracter separation, distracter interference occurred during time after peak velocity (similar amounts of interference from near and far distracters). With a large target-distracter separation, distracter interference occurred during time to peak velocity (more interference from near compared to far distracters). The results demonstrated that target-distracter separation is an important determinant of the locus of distracter interference.     

Forward association, backward association, and the false-memory illusion

In the Deese-Roediger-McDermott false-memory illusion, forward associative strength (FAS) is unrelated to the strength of the illusion; this is puzzling, because high-FAS lists ought to share more semantic features with critical unpresented words than should low-FAS lists. The authors show that this null result is probably a truncated range artifact. When FAS and its complement, backward associative strength (BAS), were independently manipulated in factorial designs, they both affected illusion strength. Moreover, their effects did not interact and were of comparable magnitude. Conjoint-recognition analyses were used to pinpoint the influence of BAS and FAS on retrieval processes that support or suppress false-memory responses. Although the variables affected both types of processes, their effects on suppressive processes were larger and more consistent. This research also provided the first clear evidence that subjects often use suppressive processes inappropriately to reject studied items that preserve the gist of experience.     

Evaluation of two methods of prompting drivers to use specific exits on conflicts between vehicles at the critical exit

The Florida Department of Transportation used a series of changeable-message signs that functioned as freeway guide signs to divert traffic to Universal Theme Park via one of two eastbound exits based on traffic congestion at the first of the two exits. An examination of crashes along the entire route indicated a statistically significant increase in crashes at the first eastbound exit following the actuation of the system. Furthermore, all of the crashes occurred in close proximity to the exit gore (the crosshatched area at exits that drivers are not supposed to enter or traverse) at the first exit. In Experiment 1, behavioral data were collected using an alternating treatments design. These data revealed that reassigning the exit signs was effective in producing a change in the percentage of drivers using each of the two exits. These data also showed that the reassignment of the theme park exit was associated with an increase in the percentage of motor vehicle conflicts that consisted of vehicles cutting across the exit gore. An analysis revealed that the method used for switching the designated or active theme park exit on the series of changeable-message signs led to the presentation of conflicting messages to some motorists, thus resulting in erratic driving behavior (cutting across the exit gore). In Experiment 2, the treatment evaluated the use of a phased method of switching the designated theme park exit to eliminate the delivery of conflicting messages. The new method for switching the designated theme park exit was not associated with an increase in motorists cutting across the exit gore.     

Whisker-based discrimination of object orientation determined with a rapid training paradigm

Rats use their large facial whiskers to discriminate the spatial features of objects. Despite numerous electrophysiological recording studies in the central trigeminal whisker representations that document neurons tuned to the direction of whisker deflection, there is no behavioral evidence to date that rats can use their whiskers to discriminate between object orientations. In the present study, we characterized whisker-dependent orientation discrimination using a one-trial learning procedure. Sprague-Dawley rats were trained and tested in a three-arm 'Y-maze' that was outfitted with 180 independently moveable bars that protruded into the arms of the maze to contact the whiskers. On the first day, the maze was configured to have two arms with only horizontal bars and a third arm with only vertical bars and rats were allowed to freely explore all arms. On the second day, rats were isolated in one arm that contained only vertical bars as a conditioned stimulus (CS) and administered three mild foot shocks. On the third day, the maze was configured identically to the first day and rats were once again allowed to freely explore the maze. We measured the percentage of time spent in each arm of the maze and found that most rats spent significantly less time in the arm containing the CS after training compared to before training. Subsequent control experiments determined that the conditioned avoidance was attributable to orientation cues, was caused by the association of the conditioned and unconditioned stimulus and was whisker-dependent. Avoidance behavior was significantly reduced when the difference between the conditioned and non-conditioned orientation difference was reduced to 45 degrees. Thus, rats can discriminate object orientation with their whiskers and an estimate of their discrimination thresholds can be rapidly acquired through the application of a one-trial learning paradigm.     

Pathological laughter as a symptom of midbrain infarction

Pathological laughter is an uncommon symptom usually caused by bilateral, diffuse cerebral lesions. It has rarely been reported in association with isolated cerebral lesions. Midbrain involvement causing pathological laughter is extremely unusual. We describe three patients who developed pathological laughter after midbrain and pontine-midbrain infarction. In two patients a small infarction in the left paramedian midbrain was detected, whereas the third one sustained a massive bilateral pontine infarction extending to the midbrain. Laughter heralded stroke by one day in one patient and occurred as a delayed phenomenon three months after stroke in another. Pathological laughter ceased within a few days in two patients and was still present at a two year follow-up in the patient with delayed-onset laughter. Pathological laughter can herald midbrain infarction or follow stroke either shortly after onset of symptoms or as a delayed phenomenon. Furthermore, small unilateral midbrain infarctions can cause this rare complication.     

Distractor interference in selective reaching: dissociating distance and grouping effects

In the present experiment, the authors sought to differentiate between a distance and a grouping explanation for the symmetric versus asymmetric patterns of distractor interference in selective reaching. Participants (N = 16) pointed to a green target that appeared either with or without a red distractor. Target-distractor separation was manipulated within an array of 5 closely grouped stimulus boxes, and distractor interference (difference in performance between trials with and trials without a distractor) was measured in reaction time, movement time, percentage errors, and movement endpoints. Small distances (5 mm) between target and distractor yielded a symmetric pattern of interference, whereas large distances (20 mm) yielded an asymmetric pattern, with more interference from near than from far distractors. Those findings support the distance account of distractor interference and refute the grouping account.     

A characterization theorem for random utility variables

In this note we investigate the condition that the distribution of the maximum of a set of random variables does not depend on which variable attains the maximum. This problem arises in random utility theory. When the random variables are independent, the property implies that all the marginal distributions must be Double Exponential (with distribution function exp(?e^?x) in standard form). When dependence is allowed the property characrerizes a much broader class consisting of arbitrary functions of arbitrary homogeneous functions of the variables e^?xi, a result stated without proof in D. J. Strauss (Journal of Mathematical Psychology, 1979, 20, 35–52). These are the distributions such that the maximum has the same distribution (apart from a location shift) as the marginals, provided the marginals are the same.     

The modification of intelligence through early experience

Infants judged to be at risk for subnormal intellectual growth were randomly assigned to an Experimental (N = 27) or a Control (N = 25) group. Infants in both groups received medical care and dietary supplements; their families received social work services on a request basis. Experimental children participated in an educational daycare program beginning before the third month of life. The daycare program was composed, in part, of curriculum activities designed to stimulate intellectual growth. Between 6 and 36 months of age, Experimental children maintained normal intellectual growth; Control children declined in IQ beginning between 12 and 18 months of age and remained significantly lower than Experimental children at 24 and 36 months. The mother-child IQ correlation for Control dyads was 43; for Experimental dyads the correlation was ?.05. These two types of evidence are interpreted as support for the importance of early environments in the development of intelligence.