RITALIN VS. RESPONSE COST IN THE CONTROL OF HYPERACTIVE CHILDREN: A WITHIN-SUBJECT COMPARISON

A within-subject comparison was made of the effects of methylphenidate (Ritalin) and response cost in reducing the off-task behavior of two boys, 7 and 8 years of age, who had been diagnosed as having an attentional deficit disorder with hyperactivity. Several dosages of Ritalin (5 to 20 mg/day) were evaluated with the results indicating varying effects of the drug for both children. Response cost (with free-time as the reinforcer) was superior to Ritalin in raising levels of on-task behavior and in improving academic performance.     

Strategies in cross-modality matching

Subjects were tested on cross-and within-modality matching conditions with either a 5-sec or a 20-sec delay imposed between standard and comparison stimuli. Half the subjects were informed before the trial of what the comparison modality would be, while the others were not. There was a strong effect of instructions on the cross-modality conditions, but little on the within-modality conditions. The informed subjects showed better performance in the haptic-visual condition, while for the uninformed subjects, visual-haptic performance was better. The results suggest the importance of subjects’ processing strategies in cross-modality performance.     

Counting eliminates the repetition effect in judgments of temporal duration.

College student subjects estimated the duration of time intervals (8–54 sec) by counting or not (N=35 per group). Counting eliminated the repetition effect (a decline in the magnitude of estimations across trials), and resulted in a truncation of the psychophysical function. The former result was interpreted as contrary to Treisman's (1963) model. The latter result was attributed to the effortfulness of counting, which was established in a subsequent experiment.     

Indirect social influence: Change in judgmental process or anticipatory conformity?

In three experiments, subjects imposed sentence in a criminal case before and after reading the harsh sentence imposed by the trial judge. They then read and imposed sentence in another case. In one experimental condition the subjects anticipated learning the judge's sentence in Case 2; in the other condition they were told not to anticipate learning the judge's sentence. Control subjects made their judgments without ever seeing the judge's sentence. Direct influence was the change in sentences within cases; indirect influence was the difference between initial sentences in Cases 1 and 2. Though direct influence was minimal and not significant, indirect influence was substantial, and was greater in the anticipation than no-anticipation than control conditions, indicating that both modification of the judgmental process and anticipatory conformity were operating. Indirect influence may then reflect a change of either type, depending on a number of methodological and other factors.     

Storage mode of geometrical dimensions in a two-stimulus matching paradigm

In a two-stimulus matching paradigm requiring “same” and “different” responses to simple geometric dimensions, the successive stimulus presentation mode with several retention intervals was compared to a simultaneous stimulus presentation mode. For the simultaneous condition, the data suggested a wholistic template matching process, but in none of the successive conditions was template matching indicated. The retention interval of the successive condition allows the subject to analyze out the target dimension from the first two-dimensional stimulus. The ability to anticipate the value of the target dimension in the second stimulus could also influence the representation of the first stimulus. The findings shed some light upon the perceptual interactions between dimensions that constitute the stimulus. In particular, an outside-to-inside order of iconic scanning appeared to be supported by the data.     

Operant conditioning of epileptic neurons in monkeys and its theoretical application to EEG operant conditioning in humans

This paper reviews a series of previous reports which summarize the physiology of chronic experimental epileptic foci in monkeys. It is shown that such monkeys can be trained to bidirectionally control the firing rates of normal and epileptic neurons which comprise the epileptic focus. As a result of this acquired operant performance, the monkeys show both a decrease in clinical seizures as well as a decrease in single unit epileptic activity. The EEC correlate of this change in single unit epileptic actvity is generalized EEG desynchronization. The conclusion from these data would indicate epileptic neurons can be operantly controlled and this control is not correlated with any specific EEG pattern. This brings to question the specificity of the SMR in EEG biofeedback paradigms which treat human epilepsy. This author feels that the result from such biofeedback studies are the result of the patient learning to manipulate electrical events within the CNS pathways through which the seizure propagates and is not contingent upon specific EEG frequencies.