Simple motor and phonemic processing reaction times of elderly subjects.

Simple motor reaction time (RT) was measured for arm movement in response to a known monosyllable presented by earphone. The required direction of movement (L or R) was known to S. Choice RT was also measured: only one word of a pair of taped monosyllabic words, differing only in the prevocalic consonant (e.g., tea-key) was presented by earphone. Simultaneously, a picture of each word appeared on response plates, one to the L and one to the R of the center rest position. S had to touch the response plate with the picture of the word heard. Subtracting simple from choice RT, in msec, yielded an estimate of auditory-phonemic processing (decoding) time. Data were collected from generally normal, healthy, elderly Ss [Grp I (10 M, 10 F) of 72 yrs mean age, and Grp II (7 M, 9 F) of 84 yrs mean age] and a control group (9 M, 9 F) of 21 yrs mean age. An ANOVA with repeated measures showed that significant differences existed among the 3 groups. A similar ANOVA procedure on phonemic processing time revealed that significant differences existed between the younger and the older Ss, but not between Grps I vs II. Collectively, these findings were taken to suggest that advanced age does not affect all behavioral operations in a generalized fashion. It was suggested that auditory-phonemic processing is more resistant to the aging process than manual responses.