Tests of randomness for pseudorandom number generators

This study examined the “randomness” of the numbers generated by the VIC-20 computer. Using eight standard tests, it was determined that the numbers provided by the VIC-20 are adequately random for practical purposes. The tests are applicable to other computer systems and provide a general means for evaluating random-number generators.     

A low-stress restraint procedure for EEG acquisition in awake rats

A restraint procedure was developed to reduce movement-related artifacts during the acquisition of EEG data from unanesthetized, unparalyzed rats. It combines the low-stress properties of a cloth restraint bag with the improved immobility of a rigid restraint device. The spontaneous behavior of the rat facilitates both the induction of and the subsequent release from restraint.     

The specificity of the effects of stimulant medication on classroom learning-related measures of cognitive processing for Attention Deficit Disorder children

There appear to be beneficial effects of stimulant medication on daily classroom measures of cognitive functioning for Attention Deficit Disorder (ADD) children, but the specificity and origin of such effects is unclear. Consistent with previous results, 0.3 mg/kg methylphenidate improved ADD children's performance on a classroom reading comprehension measure. Using the Posner letting-matching task and four additional measures of phonological processing, we attempted to isolate the effects of methylphenidate to parameter estimates of (a) selective attention, (b) the basic cognitive process of retrieving name codes from permanent memory, and (c) a constant term that represented nonspecific aspects of information processing. Responses to the letter-matching stimuli were faster and more accurate with medication compared to placebo. The improvement in performance was isolated to the parameter estimate that reflected nonspecific aspects of information processing. A lack of medication effect on the other measures of phonological processing supported the Posner task findings in indicating that methylphenidate appears to exert beneficial effects on academic processing through general rather than specific aspects of information processing.     

Enhanced right hemisphere activation in the mathematically precocious: A preliminary EEG investigation

A preliminary electroencephalographic (EEG) investigation was conducted to determine if the pattern of hemispheric activation in mathematically precocious youth differs from that of average math ability subjects. Alpha activity at four brain sites (frontal, temporal, parietal, and occipital lobes) over the left and right cerebral hemispheres (LH/RH) was monitored while 12- to 14-year-old, right-handed males: (a) looked at a blank slide (baseline condition), (b) judged which of two chimeric faces was "happier," and (c) determined if a word was a noun or a verb. At baseline, the LH of the precocious group was found to be more active at all four brain sites relative to that of the average ability group. During chimeric face processing, the gifted subjects exhibited a significant reduction in alpha power over the RH, primarily at the temporal lobe, while no such alpha suppression was observed in the average ability subjects. For noun/verb determinations, no significant alpha power reductions were obtained for either group. These electrophysiological data generally corroborate the behavioral findings of O'Boyle and Benbow (1990a) and support their contention that enhanced RH involvement during cognitive processing may be a correlate of mathematical precocity. Moreover, the pattern of activation observed across tasks suggests that the ability to effectively coordinate LH and RH processing resources at an early age may be linked to intellectual giftedness.     

Analogical transfer and expertise in legal reasoning

Analogical transfer and its relation to expertise is examined in a legal context. Three experiments were conducted comparing the performance of novices (introductory tax students) and of experts (experienced tax practitioners from multinational public accounting firms) on tasks involving the application of tax laws. In Experiment 1 subjects completed a target problem after reading a decided case that was either analogous or not analogous to a target problem. A limited amount of transfer was observed, with no differential rate of transfer across experience levels. In Experiments 2 and 3 attempts were made to facilitate transfer of knowledge by inducing transfer-appropriate processing of the source analog and by providing multiple source analogs. The results of both experiments indicate an interaction between treatment and expertise. Unexpectedly, the facilitating treatments reduced the transfer of knowledge for experts while increasing the transfer for novices. Subsequent analysis of the responses of the expert subjects indicates that for the more experienced expert subjects a highly proceduralized rule interfered with the knowledge transfer when that rule was made salient by the facilitating treatments. The less experienced expert subjects behaved in a manner consistent with the hypotheses. This poor performance of the more experienced experts results from the inflexibility in expert problem solving due to the proceduralization of information processing. Frensch and Sternberg (1989) demonstrate that this type of inflexibility is one of the costs of expertise and results from the development of a large and highly complex knowledge base containing numerous well developed strategies.     

A behavioral perspective on college teaching

Much of the subject matter learned in college, particularly during the first two years, is taught in relatively large classes with text and lecture as the primary source of the information being learned. If students make effective and prolonged contact with these sources, they can acquire extensive verbal repertoires in many areas of knowledge. Unfortunately there are many other activities that compete for the typical student's study time. Several factors are often cited as variables that will support study behavior in competition with other activities, but the only powerful one available to the teacher is the exam grade, as it is related to the course grade. However, unless exams are clearly related to appropriate study behavior, require through and extensive coverage of the subject matter, occur frequently (preferably no less often than once a week), and are also clearly related to the course grade, even this factor will not generate prolonged and effective study behavior. Effective college teaching is essentially a form of aversive control, but if done properly the aversiveness is quite mild, and such aversive control can be responsible for the development of large and valuable intellectual repertoires.     

Lithium-mediated disruptions of latent inhibition: Overshadowing by the unconditioned stimulus in flavor conditioning

In a series of experiments, the ability of a single lithium preexposure to disrupt CS effectiveness was assessed using a latent inhibition procedure. Lithium preexposure administered proximal (90 min) to a saccharin familiarization trial reduced latent inhibition whereas a similar administration more distal (360 min) to flavor familiarization failed to do so. Additional experiments demonstrated that this socalled “US overshadowing” effect was not attributable to sensitization (Experiment 2), excitatory backward conditioning (Experiment 3), or state dependency (Experiment 4). The implications of US overshadowing for proximal US-preexposure effects are discussed.