Search PubMed⌕ Search

Biomedical subjects

R A Block

Publications and source records attributed to R A Block.

13 recordsLinked to original sources
PubMed2000

Culture and beliefs about time: comparisons among black Americans, black Africans, and white Americans.

The authors investigated the extent to which racial factors, cultural factors, or both influence a person's beliefs about physical time, personal time, and experienced and remembered duration. A total of 750 Black American, Black African, and White American students responded to a questionnaire on these beliefs about time. Factor analysis was used to compare belief structures. Pairwise comparisons, performed separately for each statement, tested the direction and strength of the reported beliefs. The groups showed many similarities, but they also showed some differences. All 3 groups differed in beliefs about physical and personal time, but they did not differ in beliefs about duration experiences. This evidence does not support simplistic views of racial or cultural influences. Culture may differentially influence beliefs about physical time and personal time. Beliefs about duration experiences may represent an ethnic factor that transcends cultures.

Adolescent↗
PubMed2000

Sex differences in duration judgments: a meta-analytic review.

We quantitatively reviewed human sex differences in the magnitude and variability of duration judgments. Data from 4,794 females and 4,688 males yielded 87 effect size estimates of magnitude and 28 of variability. The overall sex difference in duration judgment magnitude was small but statistically significant. It was moderated by whether study participants knew in advance (prospective paradigm) or only later (retrospective paradigm) that they would be required to judge duration. Although prospective judgments showed no overall sex effect, some levels of moderator variables showed a small but statistically significant effect. Retrospective judgments showed a larger subjective-to-objective duration ratio for females than for males, and several variables moderated this effect. Females' judgments also showed more intersubject variability than did males' judgments. Relative to males, females sustain attention to time more in the prospective paradigm and have better episodic memory in the retrospective paradigm.

Adolescent↗
PubMed1998

Human aging and duration judgments: a meta-analytic review.

Differences in duration judgments made by younger and older adults were reviewed. Previous research is unclear about whether such differences exist and, if so, how they may be explained. The meta-analyses revealed substantial age-related differences. Older adults gave larger verbal estimates and made shorter productions of duration than did younger adults. There were no age-related differences in reproduction of duration or in psychophysical slope relating judged and target duration. Older adults' duration estimates were more variable than were those of younger ones. Findings are discussed in terms of pacemaker rate and attentional resources. An explanation regarding divided attention between nontemporal and temporal information processing best explains the findings.

Adolescent↗
PubMed1989

Unilateral nostril breathing influences lateralized cognitive performance.

Relative nostril efficiency (nasal cycle) is related to hemispheric EEG differences and performance on cognitive tasks. We investigated how unilateral forced nostril breathing influences spatial and verbal performance. Right-handed males and females performed both tasks under either left-nostril, right-nostril, or free-breathing conditions. Unilateral breathing affects performance differently in males and females. It influences male performance ipsilaterally on both tasks: Their spatial performance is better during right-nostril breathing, and their verbal performance is better during left-nostril breathing. Unilateral breathing influences female performance contralaterally, but only on the spatial task: Their spatial performance is better during left-nostril breathing. These differences within and between sexes may exist because unilateral nostril breathing differentially activates the two hemispheres and thereby facilitates performance, or because attempts of the brain to control the nasal cycle unilaterally interfere with performance.

Adult↗
PubMed1982

Temporal judgments and contextual change.

Three experiments investigated effects of environmental context on temporal memory judgments. An equal number of items occurred within each of two equal durations (D1 and D2). Subjects subsequently were asked to judge the length of a given duration in comparison with the other, then to discriminate the correct list and serial position for each recognized item on a test. If environmental context was unchanged, D1 was remembered as being longer than D2; if the context was disrupted during the interval separating D1 and D2, this effect was reduced; and if the context prevailing during D2 also was changed, the effect was eliminated. List discrimination was improved only if the context was changed. Serial-position judgment was not affected by either manipulation. Changes in process context--the internal context produced by the performance of specific cognitive processes--lengthened remembered duration, but the effect did not simply add on to the effects of environmental context. Results are discussed in terms of a contextual-change hypothesis.

Attention↗
PubMed1979

Aspiration of infected sarco-iliac joints.

Seven of eight patients with suspected sarco-iliac joint infection had the diagnosis confirmed by closed aspiration of the joint. A reproducible method of obtaining specimens for culture was developed. Failures of aspiration may occur in patients in whom anatomical variations cause segmentation of the joint, therefore preventing the septic process from involving the most posterior and caudal part.

Arthritis, Infectious↗