Slower Choice Reaction Time Research Articles

Differences between males and females with spinal cord injury in the experience of subliminal and explicit sexual pictures.

Observational cross-sectional study. To determine the differences between persons with spinal cord injury (SCI) and control individuals in terms of conscious and unconscious sexual responses to subliminally presented visual sexual stimuli. Spinal cord injury rehabilitation center in northern Italy. A two-part behavioral experiment was conducted on 40 participants (27 individuals with SCI; 13 controls). In first part, all participants were subliminally exposed to a prime picture (neutral or sexual) and asked to rate the extent to which they were emotionally aroused, while watching a set of explicit target pictures (neutral or sexual). In the second part, choice reaction time task was employed, wherein participants were shown a subliminal prime picture (neutral or sexual) followed by an explicit target picture (neutral or sexual) superimposed by a black dot and were asked to locate the dot as fast as possible. In the first part, men with SCI reported higher levels of emotional arousal to explicit sexual target pictures compared to other groups. In the second part, slower choice reaction times were found in the SCI group, particularly with sexual prime picture. Moreover, females with SCI spent more time during implicit motor learning tasks with sexual target pictures than other groups. We found differences in the experience of subliminal and explicit sexual pictures not only between the two groups, but also between females and males with SCI. Attention should thus be paid when considering sexual experience at subliminal and conscious level in SCI population for future research and rehabilitative protocols.

Self-Reported History of Chemotherapy and Cognitive Decline in Adults Aged 60 and Older: The PATH Through Life Project

There is a lack of data from cohort studies assessing cognitive function prior to and after chemotherapy. We evaluated the effect of self-reported cancer chemotherapy on cognitive function in a cohort assessed at baseline, 4 and 8 years. Participants were from the population-based PATH Through Life Study. Of the 2,551 participants aged 60-64 at baseline without cognitive impairment, 1,949 completed wave 3 and had data on cancer and chemotherapy and cognitive function. Linear mixed models were used to analyze the data. At wave 3, participants reporting history of chemotherapy (n = 76) had lower scores on memory, processing speed, and executive function compared with those reporting cancer without chemotherapy (n = 289) and no cancer history (n = 1508). After adjustment for depression and disability, effects remained for processing speed and memory. Chemotherapy prior to the study commencement (n = 24), but not between waves 1 and 3 (n = 81), was associated with greater decline in delayed recall (β = -.21 [95% CI -0.38, -.03], p = .02) and digits backwards β = -.05 [95% CI -0.09, -.01], p = .02) over 8 years compared with those with no cancer history (n = 1562). Women reporting chemotherapy for breast cancer after wave 1 (n = 26) had slower choice reaction time (-0.81 (95% CI -1.28, -0.34), p = .001) but did not decline faster on this measure compared with those reporting no breast cancer history (n = 818). Results suggest chemotherapy prior to old age is associated with faster decline in memory in late life but that it does not affect decline in other domains of cognitive function.

Useful Visual Field in Patients with Schizophrenia: A Choice Reaction Time Study

This study examined the size of the useful visual field in patients (9 men, 6 women) with schizophrenia. A choice reaction task was conducted, and performances at 2.5, 5, 7, 10, and 25 degrees in both visual fields were measured. Three key findings were shown. First, patients had slower choice reaction times (choice RTs) than normal controls. Second, patients had slower choice RTs in the right visual field than in the left visual field. Third, patients and normal controls showed the same U-shaped choice RT pattern. The first and second findings were consistent with those of other studies. The third finding was a clear indication of the patients' performance in peripheral vision, and a comparison with normal controls suggested that there was no difference in the size of the useful visual field, at least within

Choice Reaction Time Difference Between Gender and Hand Using the Fractionated Reaction Time Technique

A gender difference in choice reaction time (RT) has been reported in the literature (e.g., Adam et al., 1999; Noble et al., 1964). Noble, Baker and Jones found that females had slower choice RT than their male counterparts many years ago. Later study by Adam et al. also reported a faster choice RT for male participants. Since Weiss (1965) introduced the measurement of RT components with electromyography (EMG), pre-motor time (PMT) and motor time (MT) have been used to identify the central (cognitive) and peripheral (neuromuscular) processing of the initiation of voluntary movement in human performance research. PURPOSE: To examine whether choice reaction time and its fractionated components differ between genders and dominant and non-dominant hands. METHODS: Twenty right-hand dominant college students (10 male, 26.0 ± 3.06 yrs; 10 female, 25.4 ± 2.27 yrs) were tested for their visual-manual choice reaction time for four consecutive days using both left and right hands. Based on the EMG activity of the pronator teres and biceps brachii, fractionated RTs of pronation and supination were measured for each hand. The learning effect was identified and a reliable measure was obtained. A 2 (gender) by 2 (hand) two-way mixed design analysis of variance (ANOVA) was used to analyze possible gender and hand difference as well as their interaction. RESULTS: Choice RT decreased across days (p < .05), however, no significant change was found between days 3 and day 4. No Gender x Hand interaction or hand difference was observed for choice RT. A significant gender difference was observed for total choice RT (F1,18 = 6.43, p < .05). The mean choice RT for the males was 278 ms, and for the females it was 308 ms. A further analysis of PMT and MT indicated that male participants had a faster PMT (218 ms) than female (246 ms) participants (F1,18 = 6.51, p < .05), but no MT difference was observed between the gender groups. CONCLUSIONS: There is no choice reaction time difference between dominant and non-dominant hands for the college students. Male participants demonstrated a faster choice RT than female participants, and the difference in total choice RT can be attributed to the PMT component, but not MT. The finding supports the proposed explanations that males might have employed a binary strategy while females used a serial strategy in choice reaction time tasks.

There are stable individual differences in performance variability, both from moment to moment and from day to day.

Individual differences in decision speed have been regarded as direct reflections of a "primitive" functional neurophysiological characteristic, which affects performance on all cognitive tasks and so may be regarded as the "biological basis of intelligence", or of age-related changes in mental abilities. More detailed analyses show that variability within an experimental session (WSV) is a stable individual difference characteristic and that mean choice reaction times (CRTs) are gross summary statistics that reflect variability, rather than maximum speed of performance. A total of 98 people aged from 60 to 80 years completed 36 weekly sessions on six different letter categorization tasks. After effects of practice and of circadian variability had been eliminated, individuals with lower scores on the Cattell Culture Fair intelligence test had slower CRTs and greater WSV on all tasks. A simulation study showed that the greater WSVs of low Cattell scorers led directly to the significantly greater variability of their mean CRTs from session to session. However because CRTs on tasks co-varied from session to session it was apparent that, besides being affected by WSV, individuals' between-session variabilities (BSVs) also vary because of state changes that affect their performance from day to day. It seems that both variability in performance from trial to trial during a session and variability in average performance from day to day are correlated, stable, individual difference characteristics that vary inversely with intelligence test performance. Methodological consequences of these results for interpretations of age-related cognitive changes, for variability between as well as within individuals, for individual differences in decision speed, and for circadian variability in performance are discussed.

Contrast discrimination and choice reaction times at near-threshold pedestals.

Choice reaction times (CRTs) to contrast differences were measured and compared with contrast increment thresholds obtained from concurrently measured psychometric functions at pedestal contrasts in the vicinity of detection threshold. Contrast discrimination functions had a classical dipper shape. The main finding was that CRTs were shorter at low pedestal contrasts but longer at higher pedestal contrasts compared to detection, reflecting the behaviour of increment thresholds. Even when equalized for response accuracy, CRTs varied with pedestal contrast in a similar manner to the contrast increment thresholds. The finding that CRTs and contrast increment thresholds depended on pedestal contrast in a similar manner suggests that both share a common origin. This common origin is proposed to lie in the variability of the sensory effect which determines the variability of the information accumulation process, which in turn affects the response criterion and contrast increment thresholds. At low pedestals, a decrease in variability lowers thresholds and results in a lower response criterion, thereby accelerating reaction times. At high pedestals, increasing signal-dependent noise inflates variability and thus raises thresholds and the response criterion, which results in slower CRTs.

Slower and more variable reaction times in schizophrenia: what do they signify?

Extensive research has demonstrated that schizophrenic subjects are slower than normal comparison subjects on a range of reaction-time tasks. Some investigators have also observed that schizophrenic patients exhibit larger intra-individual variability in reaction times when performing these tasks than do normal comparison subjects. This study, using a lexical decision choice reaction time (CRT) task, explored the relation of mean CRT and its intra-individual variability (CRT-SD) to psychiatric symptoms and to performance on executive-motor tasks in 26 medication-free schizophrenic out-patients and 17 normal comparison subjects. Schizophrenic subjects had both significantly slower and more variable CRTs which were unrelated to general intellectual abilities (IQ). Among schizophrenic subjects, both CRT and CRT-SD were significantly related to severity of psychotic symptoms, failure to maintain cognitive set, and poorer motor coordination and global functioning. After controlling for mean CRT, CRT-SD showed unique covariation with clinical symptoms (positive, disorganized and tension/hostility). Conversely, mean CRT showed unique covariation with the failure to maintain cognitive set and with stereotypic mannerisms, independent of CRT-SD. These results suggest that slower CRT and increased intra-individual variability in CRT, while not fully independent of one another, may reflect separate aspects of symptomatic and cognitive dysfunction in schizophrenia.

THE EFFECTS OF HUNTINGTON'S DISEASE ON MIDLINE CROSSING ABILITY 45

Our purpose was to determine whether individuals with Huntington's Disease(HD) display an inhibition to cross the midline (MCI) of their body when performing a choice reaction time (CRT) and movement time (MT) task with the lower extremity. Persons with HD (n=14) and at no risk for HD (n=14) were assessed on 6 days using a method based on the information processing paradigm. CRT and MT were measured prior to and upon completion of a contralateral, ipsilateral or midline movement. The rationale for this method was that contralateral movement represented a more complex task then an ipsilateral or midline movement. Slower CRTs and MTs for contralateral movements would be the result of MCI. A 2 × 6 × 3 ANOVA (group× testing day × direction) was conducted to analyze the CRT and MT data. For CRT, a significant (p<.05) group × testing day × direction interaction was found. Post hoc analysis determined that MCI was displayed only by persons with HD on all testing days. The post hoc analysis of the significant (p<.05) group × direction interaction for MT revealed that persons with HD moved more slowly when crossing their midline as well as exhibiting slower MTs in all directions than persons without risk. The assessment of MCI may provide insight into motor impairment associated with HD and may also be a method to monitor motor degeneration.