Vocal versus manual response as a determinant of age difference in simple reaction time.

The decrease in response speed usually found to occur with advancing age is felt by many investigators to be a phenomenon common to all speeded tasks, regardless of the exact nature of the sensory stimulus or motor response involved. In the present experiment, however, the type of response the subject made determined whether or not an age difference existed in simple reaction time to a visual stimulus. When subjects responded manually, by releasing a key, the usual age decrement in response latency was found. When the same subjects responded vocally, by saying a word, there was no significant age difference in reaction time. This result suggests that slowing of psychomotor latency with age is not a general phenomenon, but may be limited to certain neural systems.