Cerebral laterality and verbal-performance discrepancies in intelligence

The cerebral laterality of children with various configurations of verbal-performance discrepancies was inferred with an objective measure of lateral preference. Specifically, Verbal and Performance IQ scores of the WISC-R were used to divide 90 learning-disabled children into three equal groups: (a) Verbal significantly higher than Performance, (b) Performance significantly higher than Verbal, and (c) Verbal not significantly different from Performance. Analysis of the scores on the Laterality Preference Schedule showed children in the Verbal > Performance group were significantly more bilateral in their preference patterns than either of the other groups. Data on familial laterality showed this Verbal > Performance group to also have parents who were significantly more mixed in their preference patterns than either the VSIQ < PSIQ or VSIQ = PSIQ groups. The results were interpreted as lending support to the notion of competition antagonism between cortical hemispheres and a possible genetic relationship.     

Values of British political extremists and potential extremists: A discriminant analysis

Studied the value systems of political extremists and potential extremists, comparing them with the value systems of centrist activists and supporters. Samples of political activists from the Labour, Conservative, Communist and National Front parties were obtained, as well as samples of non-active supporters. The non-active supporters were defined as Potential Extremists, if they supported a centrist party as first choice, but either Communist or National Front as second choice. All subjects completed the Rokeach Value Survey. Discriminant analysis showed that the four groups of activists could be clearly distinguished on the bask of their values. However the values of the Potential Extremists did not especially resemble the values of actual National Front or Communist activists. There were value differences between the Potential Extremists and the centrist supporters; nevertheless these two groups tended to be distinguished by very different values from those which distinguished between the activists. The appeal of value symbols for different types of political involvement was discussed.     

Handedness and stuttering: A dead horse?

A handedness questionnaire was administered to 446 stutterers and a control group. No significant male/female or stutterer/control effects were found, although both males and stutterers tended to be less right handed. The slight sex effect in handedness is consistent with previously reported studies and with cerebral structural and functional asymmetries.     

Measuring circadian cycles: A simple temperature recording preparation

While measurement of temperature as an index of circadian rhythmicity is not a difficult task with infrahuman subjects, long-term monitoring of deep body temperature with human subjects poses numerous measurement and safety problems. A preparation is described that is highly accurate, inexpensive, chronic, comfortable, and eliminates safety problems associated with more traditional methods of temperature measurement.     

Vowel recognition: Inferences from studies of forward and backward masking

The recognition of brief vowels was studied in forward and backward masking tasks. In a series of experiments in which both target and mask parameters were systematically varied, two populations of subjects were identified. The majority (Nonmaskers) evidenced little masking at any interstimulus interval, while relatively fewer subjects (Maskers) evidenced backward masking (but not forward masking) over a 100-200 ms interval. Increasing target set size systematically increased masking for the Maskers but not for the Nonmaskers. Adding white noise to the targets increased the extent of masking for both groups. These results suggest (1) that masking does not impose a substantive constraint on vowel perception in running speech, and (2) that multiple strategies may exist for vowel recognition.     

The effect of alcoholic intoxication upon calorically induced oculogyral illusion

Ten male and 10 female subjects, half of whom were classified as “heavy” and half as “light” drinkers, ingested a 4-1 combination of tonic water and 80-proof vodka in an amount calculated to produce a state of moderate intoxication (average estimated peak blood alcohol level=.075). This resulted in an increased sensitivity (latency, magnitude, and duration) to the calorically induced “oculogyral illusion” (OGI) relative to a placebo (tonic water) condition. “Heavy” and “light” drinkers did not differ significantly on any of the measures. It was speculated that the alcoholic enhancement of the OGI was due either to a decreased ability to suppress vestibular nystagmus when attempting to fixate a visual stimulus or to the expenditure of extra-normal effort in order to maintain fixation.     

Fast regression estimates of missing data

A recent comparison of methods for estimating missing data concluded that when there is sufficient redundancy to justify using a more elaborate method than the mean of each variable, the principal components and regression methods are equally good and superior to the other methods investigated. Principal components was preferred because of its tremendous computational savings over the regression method. This note proposes an alternate implementation of the regression method which should be slightly faster than the principal components method.     

Effects of postresponse visual stimuli on visual discrimination learning in the rhesus monkey

To learn more about the mechanism (or mechanisms) involved with postresponse stimulus processing during discrimination learning, a series of studies was conducted with monkeys to determine why the combined relevant and irrelevant stimuli impair learning more than irrelevant stimuli appearing alone. It was found that: (a) the greater size and complexity of the combination of stimuli were not responsible for the greater deficit, while the presence of the relevant stimuli (S^D and S^Δ) within the stimulus combination apparently was; (b) the more similar the postresponse irrelevant stimuli were to the relevant stimuli the greater the deficit that resulted; and (c) monkeys that had earlier learned to discriminate the relevant and irrelevant features of a combination showed no learning impairment when this same stimulus combination was later presented after the response during a new learning problem. These results were interpreted as evidence that: (1) processes associated with learning a discrimination problem do not end with the execution of a choice response; (2) postresponse stimuli produce greater impairment in discrimination learning when they are distorted versions of the relevant stimuli; and (3) the impairment resulting from postresponse irrelevant stimuli occurs primarily when this misinformation is processed and misperceived as being relevant to learning the discrimination problem.