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Factors influencing the latency of simple reaction time.

Woods DL, Wyma JM, Yund EW, Herron TJ, Reed B - Front Hum Neurosci (2015)

Bottom Line: Mean SRT latencies were short (231, 213 ms when corrected for hardware delays) and increased significantly with age (0.55 ms/year), but were unaffected by sex or education.SRT latencies increased with age while SDT latencies remained stable.Precise computer-based measurements of SRT latencies show that processing speed is as fast in contemporary populations as in the Victorian era, and that age-related increases in SRT latencies are due primarily to slowed motor output.

View Article: PubMed Central - PubMed

Affiliation: Human Cognitive Neurophysiology Laboratory, Veterans Affairs Northern California Health Care System, Martinez CA, USA ; The Department of Neurology, University of California Sacramento, Davis CA, USA ; Center for Neurosciences, University of California Davis, Davis CA, USA ; Center for Mind and Brain, University of California Davis, Davis CA, USA.

ABSTRACT
Simple reaction time (SRT), the minimal time needed to respond to a stimulus, is a basic measure of processing speed. SRTs were first measured by Francis Galton in the 19th century, who reported visual SRT latencies below 190 ms in young subjects. However, recent large-scale studies have reported substantially increased SRT latencies that differ markedly in different laboratories, in part due to timing delays introduced by the computer hardware and software used for SRT measurement. We developed a calibrated and temporally precise SRT test to analyze the factors that influence SRT latencies in a paradigm where visual stimuli were presented to the left or right hemifield at varying stimulus onset asynchronies (SOAs). Experiment 1 examined a community sample of 1469 subjects ranging in age from 18 to 65. Mean SRT latencies were short (231, 213 ms when corrected for hardware delays) and increased significantly with age (0.55 ms/year), but were unaffected by sex or education. As in previous studies, SRTs were prolonged at shorter SOAs and were slightly faster for stimuli presented in the visual field contralateral to the responding hand. Stimulus detection time (SDT) was estimated by subtracting movement initiation time, measured in a speeded finger tapping test, from SRTs. SDT latencies averaged 131 ms and were unaffected by age. Experiment 2 tested 189 subjects ranging in age from 18 to 82 years in a different laboratory using a larger range of SOAs. Both SRTs and SDTs were slightly prolonged (by 7 ms). SRT latencies increased with age while SDT latencies remained stable. Precise computer-based measurements of SRT latencies show that processing speed is as fast in contemporary populations as in the Victorian era, and that age-related increases in SRT latencies are due primarily to slowed motor output.

No MeSH data available.


Mean SRTs as a function of preceding SOA. From Experiment 1 and Experiment 2. Error bars show 95% confidence intervals. X, SOA step size (200 ms in Experiment 1 and 250 ms in Experiment 2).
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Figure 3: Mean SRTs as a function of preceding SOA. From Experiment 1 and Experiment 2. Error bars show 95% confidence intervals. X, SOA step size (200 ms in Experiment 1 and 250 ms in Experiment 2).

Mentions: Stimulus onset asynchronies had a highly significant effect on SRTs [F(4,5848) = 1419.79, p < 0.0001, ω2 = 0.49], as shown in Figure 3. SRTs were prolonged (by roughly 15%) at the shortest SOA. The SOA effect size was large, and power analysis indicated that a 99% probability of detecting a significant (p < 0.05) effect of SOA would require only 10 subjects. Age did not alter SOA effects, with the Age-Group × SOA interaction failing to reach significance [F(24,5848) = 2.09, p < 0.06]. RT variance also increased at the shortest SOA [F(4,5848) = 126.47, p < 0.0001, ω2 = 0.08], again without a significant Age-Group × SOA interaction.


Factors influencing the latency of simple reaction time.

Woods DL, Wyma JM, Yund EW, Herron TJ, Reed B - Front Hum Neurosci (2015)

Mean SRTs as a function of preceding SOA. From Experiment 1 and Experiment 2. Error bars show 95% confidence intervals. X, SOA step size (200 ms in Experiment 1 and 250 ms in Experiment 2).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4374455&req=5

Figure 3: Mean SRTs as a function of preceding SOA. From Experiment 1 and Experiment 2. Error bars show 95% confidence intervals. X, SOA step size (200 ms in Experiment 1 and 250 ms in Experiment 2).
Mentions: Stimulus onset asynchronies had a highly significant effect on SRTs [F(4,5848) = 1419.79, p < 0.0001, ω2 = 0.49], as shown in Figure 3. SRTs were prolonged (by roughly 15%) at the shortest SOA. The SOA effect size was large, and power analysis indicated that a 99% probability of detecting a significant (p < 0.05) effect of SOA would require only 10 subjects. Age did not alter SOA effects, with the Age-Group × SOA interaction failing to reach significance [F(24,5848) = 2.09, p < 0.06]. RT variance also increased at the shortest SOA [F(4,5848) = 126.47, p < 0.0001, ω2 = 0.08], again without a significant Age-Group × SOA interaction.

Bottom Line: Mean SRT latencies were short (231, 213 ms when corrected for hardware delays) and increased significantly with age (0.55 ms/year), but were unaffected by sex or education.SRT latencies increased with age while SDT latencies remained stable.Precise computer-based measurements of SRT latencies show that processing speed is as fast in contemporary populations as in the Victorian era, and that age-related increases in SRT latencies are due primarily to slowed motor output.

View Article: PubMed Central - PubMed

Affiliation: Human Cognitive Neurophysiology Laboratory, Veterans Affairs Northern California Health Care System, Martinez CA, USA ; The Department of Neurology, University of California Sacramento, Davis CA, USA ; Center for Neurosciences, University of California Davis, Davis CA, USA ; Center for Mind and Brain, University of California Davis, Davis CA, USA.

ABSTRACT
Simple reaction time (SRT), the minimal time needed to respond to a stimulus, is a basic measure of processing speed. SRTs were first measured by Francis Galton in the 19th century, who reported visual SRT latencies below 190 ms in young subjects. However, recent large-scale studies have reported substantially increased SRT latencies that differ markedly in different laboratories, in part due to timing delays introduced by the computer hardware and software used for SRT measurement. We developed a calibrated and temporally precise SRT test to analyze the factors that influence SRT latencies in a paradigm where visual stimuli were presented to the left or right hemifield at varying stimulus onset asynchronies (SOAs). Experiment 1 examined a community sample of 1469 subjects ranging in age from 18 to 65. Mean SRT latencies were short (231, 213 ms when corrected for hardware delays) and increased significantly with age (0.55 ms/year), but were unaffected by sex or education. As in previous studies, SRTs were prolonged at shorter SOAs and were slightly faster for stimuli presented in the visual field contralateral to the responding hand. Stimulus detection time (SDT) was estimated by subtracting movement initiation time, measured in a speeded finger tapping test, from SRTs. SDT latencies averaged 131 ms and were unaffected by age. Experiment 2 tested 189 subjects ranging in age from 18 to 82 years in a different laboratory using a larger range of SOAs. Both SRTs and SDTs were slightly prolonged (by 7 ms). SRT latencies increased with age while SDT latencies remained stable. Precise computer-based measurements of SRT latencies show that processing speed is as fast in contemporary populations as in the Victorian era, and that age-related increases in SRT latencies are due primarily to slowed motor output.

No MeSH data available.