Biomedical subjects

M T Banich

Publications and source records attributed to M T Banich.

11 recordsLinked to original sources

PubMed1992

Interhemispheric interaction affected by computational complexity.

The present study investigated whether dividing information between the hemispheres becomes more advantageous to task performance as computational complexity increases. We hypothesized that interhemispheric processing would benefit performance especially for computationally complex tasks, whereas it would hinder performance for relatively simple ones. A letter-matching task was given to 23 subjects at three levels of computational complexity. Complexity was varied either by increasing the number of inputs to be processed or by the nature of the decision to be made. The results indicated that each of these manipulations of complexity influenced performance by making it more advantageous to have both hemispheres involved in processing rather than just one. Furthermore, the effects of each manipulation were separable.

Adolescent↗

PubMed1992

Variations in lateralized processing among right-handers: effects on patterns of cognitive performance.

Two experiments investigated whether individual differences among right-handers in patterns of lateralized processing were related to level of performance on a variety of cognitive tasks presented under non-tachistoscopic conditions. Subjects were divided into two groups of individuals, those who characteristically have greater than average right-hemisphere involvement in functioning and those who characteristically have greater than average left-hemisphere involvement. In the first experiment we examined whether characteristic individual differences in hemispheric involvement could predict performance on a facial memory task. The group with relatively greater right-hemisphere involvement had better recognition memory than the group with relatively greater left-hemisphere involvement. In the second experiment, we examined whether individual differences in hemispheric involvement could predict performance on a larger set of cognitive tasks. The groups were administered two tasks selected to evaluate left-hemisphere function and two selected to evaluate right-hemisphere function. The results indicated that the groups differed in their profile of cognitive performance. Individuals with greater than average right-hemisphere involvement in processing tended to perform better on tasks indexing right-hemisphere function than on tasks indexing left-hemisphere function, whereas the opposite was true of individuals with greater than average left-hemisphere involvement. Collectively, the results of these two experiments indicate that individual differences in lateralized performance have important implications for individual differences in patterns of cognitive ability.

Adult↗

PubMed1992

The sum of the parts does not equal the whole: evidence from bihemispheric processing.

The 5 experiments in this article examine whether bihemispheric processing can be predicted from the processing observed when information is directed initially to just 1 hemisphere. Ss decided if laterally presented words rhymed with a previously presented central target. Trials varied in the degree to which the information displayed was redundant. On some trials, the same word appeared twice; in others, different words appeared, but they both led to the same decision; and finally, on some trials, different words appeared, each of which also led to a different decision. The patterns found for unilateral and bilateral trials were distinct. Furthermore, the pattern observed on bilateral trials could not be predicted from that found on unilateral trials, suggesting that interhemispheric interaction cannot be surmised from observing a hemisphere processing information in relative isolation.

Adult↗

PubMed1991

Inter-versus intrahemispheric concordance of judgments in a nonexplicit memory task.

Performance for explicit probed recollection of an item's presentation is usually superior when initial presentation and probe are directed to the same hemisphere than when they are directed to opposite hemispheres. The present study explored whether a same-hemisphere advantage could also be observed for a nonexplicit memory task by examining concordance for initial and subsequent ratings of line length. Results indicated that mean ratings of line length differed less between initial and subsequent presentation when the lines were viewed in the same rather than opposite visual fields. This finding held even though mean ratings for initial presentation of items in the right and left visual fields did not differ. These findings suggest that the same-hemisphere advantage is a relatively basic characteristic of memorial processing in the hemispheres.

Adult↗

PubMed1991

Effects of acute aspartame and acute alcohol ingestion upon the cognitive performance of pilots.

Anecdotal evidence has associated the artificial sweetener aspartame with a number of symptoms of central nervous system (CNS) dysfunction. There are, however, little scientific data concerning the effect of aspartame upon complex mental operations such as those necessary for flying an aircraft. Thirteen pilots were tested in a double-blind study using the SPARTANS cognitive test battery of aviation-relevant information-processing tasks. These tasks relate to perceptual-motor abilities, spatial abilities, working memory, attentional performance, risk taking, processing flexibility, planning and sequencing ability. Subjects were tested over five sessions consisting of pretest and posttest controls and three randomly ordered treatment sessions. The treatment conditions involved an aspartame dose of 50 mg/kg body weight, a placebo condition, and an ethyl alcohol (0.1% BAL) condition as the positive control. No detectable performance decrements were associated with the aspartame condition, although decrements in psychomotor and spatial abilities were detected in the ethanol condition. Results were found to be consistent with prior flight-simulator studies of alcohol, but do not appear to support the concerns expressed in anecdotal testimony regarding the deleterious effects of aspartame upon cognitive performance.

Aerospace Medicine↗

PubMed1991

Testing the tests--an empirical evaluation of screening tests for the detection of cognitive impairment in aviators.

The FAA has expressed concern that flight safety could be compromised by undetected cognitive impairment in pilots due to conditions such as substance abuse, mental illness, and neuropsychological problems. Interest has been shown in the possibility of adding a brief "mini-mental exam," or a simple automated test-battery to the standard flight medical to screen for such conditions. The research reported here involved the empirical evaluation of two "mini-mental exams," two paper-and-pencil test batteries, and a prototype version of an automated screening battery. Sensitivity, specificity, and positive predictive value were calculated for each sub-task in a discriminant study of 54 pilots and 62 individuals from a heterogeneous clinical population. Results suggest that the "mini-mental exams" are poor candidates for a screening test. The automated battery showed the best discrimination performance, in part because of the incorporation of dual-task tests of divided attention performance. These tests appear to be particularly sensitive to otherwise difficult-to-detect cognitive impairments of a mild or subtle nature. The use of an automated battery of tests as a screening instrument does appear to be feasible in principle, but the practical success of a screening program is heavily dependent upon the actual prevalence of cognitive impairment in the medical applicant population.

Adult↗

PubMed1990

The effects of developmental factors on IQ in hemiplegic children.

The effects of early unilateral brain lesions on subsequent intellectual functioning were explored in hemiplegic children with congenital or acquired lesions. For congenital hemiplegics who sustained damage pre- or perinatally, lower intellectual functioning (IQ) was most highly associated with longer elapsed time since lesion. Moreover, including lesion size as an additional predictor of IQ did not account for significantly more variance than elapsed time since lesion alone. In contrast, for acquired hemiplegics who sustained damage after birth, lower intellectual functioning was highly associated with larger lesion size. In this group neither elapsed time since lesion nor age at testing accounted for significantly more IQ variance than lesion size alone. Possible effects of maturational factors and functional plasticity are considered in interpreting this pattern of results.

Adolescent↗

PubMed1990

Interhemispheric interaction: how do the hemispheres divide and conquer a task?

The present studies investigated how dividing processing between the hemispheres affects task performance. In particular, they examined whether dividing processing between the hemispheres leads to a performance advantage only when task demands exceed a certain threshold. In Experiment 1 processing demands were manipulated by varying the difficulty of the decision process. In the more difficult task, subjects decided as quickly as possible whether two of three letters had the same name (e.g. A a), whereas in the less difficult task they simply decided whether two of the three were physically identical (e.g. A A). As expected, dividing processing between the hemispheres aided performance for the more difficult name-identity task whereas it actually hindered performance for easier physical-identity task. In Experiment 2, subjects made a physical-identity decision about a different stimulus, digits. The pattern of results found in Experiment 1 for the physical-identity task was replicated; interhemispheric processing hindered task performance. These results indicate that the physical characteristics of a stimulus have minimal influence on the extent to which interhemispheric processing aids task performance. In Experiment 3, subjects were required to make more difficult decisions about digits. In one task, they decided whether the sum of two of the three digits was greater than or equal to 10, and in the other they decided if the value of a particular digit was less than either of the other two. Dividing processing between the hemispheres led to faster performance for both tasks, similar to the results for the name-identity condition. In sum, these experiments suggest that when task requirements are demanding, performance is enhanced by distributing processing across the hemispheres.

Adult↗

PubMed1990

Interhemispheric processing in left- and right-handers.

Inter- and intrahemispheric processing for left- and right-handers were compared in two experiments. In one, subjects performed a digit-matching task and in the other they decided if two letters were part of a previously presented word. On some trials the matching items were presented initially only to one hemisphere (within-hemisphere trials), and hence the match decision could be reached by a hemisphere in isolation. On other trials, one item of the match pair was presented to each hemisphere (across-hemisphere trials), requiring interhemispheric interaction for the match decision. Patterns of performance on within-as compared to across-hemisphere trials were identical for the two handedness groups in both experiments. Furthermore, individual characteristics of subjects such as their hand posture, sex and family history of left-handedness did not affect the pattern of performance. These results suggest that interhemispheric processing may not differ between right- and left-handers.

Brain↗

PubMed1989

Aesthetic preference and picture asymmetries.

Previous research has shown that when right-handed subjects prefer one orientation of a picture over its mirror image, the more interesting or important content is on the right. Location of content, however, is only one of a number of possible asymmetric aspects of picture composition. To determine whether the relationship between aesthetic preference and cerebral asymmetry is affected by the interaction of different aspects of asymmetric information in a slide, the present study examined both asymmetry of content and asymmetry of motion. The results indicated that asymmetry of both content and motion combined to influence orientation preferences of right-but not left-handers. Thus, at least two asymmetric components of picture composition interact with brain organization to influence aesthetic judgements.

Esthetics↗

PubMed1989

Neuropsychological screening of aviators: a review.

The Federal Aviation Administration (FAA) is currently investigating the possibility of including a mini-mental status exam as part of the Aviation Medical Exam. We review evidence that if such a policy is to be implemented, present mental status tests are likely to be inadequate for the job for two reasons. First, they are likely to tap a level of cognitive ability below that required for proficient piloting and second, they may not tap some cognitive skills that are relevant to aviation. We suggest that a new mini-mental status test comprised of already existing neuropsychological tests could be devised that would overcome these difficulties.

Aviation↗