Correlates of within-person (across-occasion) variability in reaction time.
A total of 420 adults between 18 and 91 years of age carried palm pilot (Palm M100; PalmOne, Milpitas, CA) devices and performed several reaction time trials when prompted at random times during the day. On the average, within-person variability in median reaction time from one occasion to the next was nearly the same magnitude as the between-persons variability in across-occasion mean reaction time. Analyses controlling the variation in one variable when examining relations involving the other variable suggested that an individual's mean reaction time is a more powerful predictor of relations with age and with the level of various cognitive abilities than his or her across-occasion SD.
Salthouse
Timothy A
TA
Department of Psychology, University of Virginia, Charlottesville, VA 22904, USA. salthouse@virginia.edu
Berish
Diane E
DE
D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D034201:Computers, Handheld; D005260:Female; D006801:Humans; D008297:Male; D008606:Mental Processes / Q000502:physiology; D008875:Middle Aged; D009483:Neuropsychological Tests; D015588:Observer Variation; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology*; D012044:Regression Analysis; D013997:Time Factors