Perceptual and Motor Skills, 1978,47, 863-867. @ Perceptual and Motor Skills 1978
REACTION TIME OF THE FINGERS WITH RESPONSES MEASURED O N A TYPEWRITER KEYBOARD1 V. HAYES AND GERALD HALPIN
Auburn University Summary.-Reaction times on each of the eight fingers were obtained for 24 skilled typists using an electric typewriter and a mechanical timer. Repeated-measures analysis of variance indicated significant differences among the mean reaction times of the eight fingers. Scheffe's multiple-comparison procedure indicated that the mean reaction time of each finger differed from that of every other finger and that the mean reaction time of the fingers on the left hand was significantly slower than the mean reaction time of fingers on the right hand. The average inter-class correlation coefficient among the fingers was .92 which indicated rank-order of reaction times to be similar across fingers.
A basic motor trait which has been measured in numerous skill studies and which has been viewed as a component of skill performance is reaction time. The ability to react quickly to a stimulus is in part due to the intrinsic speed with which a given muscle can contract. This appears to depend on the physiochemical properties of the muscles' contractile materials. The speed at which the nerve impulse can be propagated to the cenual nervous system from the sensory receptor and from the central nervous system to the muscle is also a factor affecting reaction time (Clarke, 1975). Since muscle type and quality and speed of nerve conduction differ among individuals and even within individuals, there is believed to be little generality among limbs with regard to reaction time (Henry & Rogers, 1960; Lotter, 1960; Clarke & Glines, 1960). Because rates at which typists can copy printed material vary from typist to typist and because that copying process requires response of the fingers to visual cues, there is a need for more information relative to the ability of typists to move the fingers in response to a visual cue. No data have been located which specifically relate to the reaction time, finger by finger, of typists with responses made and timed at the typewriter keyboard. Gatewood (1920) measured reaction time of the fingers singly and in pairs to one or two response keys, respectively, with a light as stimulus. Gatewood's interest was in the use of the fingers on the piano keyboard, but her seven subjects made their responses on a contrived response board and not on a piano keyboard. She noted differences among the reactions of the several fingers as well as a difference between the left and right hand-the right hand being the faster. 'Reprints may be requested from Virginia Hayes, Department of Vocational and Adult Education, School of Education, Auburn University, Auburn, Alabama 36830.
Hoke (1922) counted the number of strokes each of 96 subjects could make in 30 sec. on each of the home row keys on the typewriter. The reaction time factor was not used. It seems, however, that his measurements would depend on strength and endurance as much as or more than on speed since the median number of strokes ranged from 106 to 166 across the fingers-probably a very tiring task on manual typewriters manufactured prior to 1922. Also, group testing was used and variation among machines would have been expected. However, based on the total number of strokes made by each hand, Hoke concluded that the ratio of the ability of the right hand to that of the left is 100 to 88.87, or approximately as 1 0 is to 9 and that differences exist among the fingers. In a recent study by Hayes, Wilson, and Schafer (1977) which was designed to study the relationship between reaction time and typewriting rate of skilled typists, a significant correlation was found between typewriting rate and the difference between the reaction time of the hands, leading to a conclusion that the more similar are the hands in reaction time, the higher the typewriting rate. That study, however, did not include an analysis of the finger-by-finger reaction times of the subjects. A better understanding of the physiological characteristics of typists should have implications for instructional methodology in typewriting as well as contribute to what is known about reaction time of the individual fingers. This study, therefore, was designed to: ( 1 ) determine if reaction times differed among the fingers of skilled typists, ( 2 ) determine if the mean reaction times of the fingers on the right hand differed significantly from the mean reaction times of the fingers on the left hand, and ( 3 ) determine if there was consistency of reaction times across the fingers of individual typists. METHOD Subjects Subjects were 24 typists ranging in age from 19 to 39 yr. who had demonstrated in a testing situation the ability to copy paragraphed material with an average of 1.5 syllables per word at a minimum rate of 40 words a minute for 5 min. with 5 errors or less. Components of the testing apparatus were: IBM Selectric typewriter, Hunter Model 120A KlockKounter, Series D (interval timer) and Model 6302A Initiator. The timer, once reset to zero, was started by a contact closure and stopped by a different contact closure. Thus, the Model 6 3 0 2 4 Initiator started the timer and simultaneously illuminated the stimulus light. A stroke on the keyboard of the typewriter activated the typewriter's normal printing cycle, and a switch attached to the printing mechanism stopped the timer.
RT OF FINGERS IN TYPING
The apparatus was assembled in a testing station in the business education laboratory. Each subject was given a time between 1 p.m. and 3 p.m. to report to the lab for individual testing. Prior to the reaction time test the subject was given 5 min. to adjust his position at the typewriter and to become accustomed to the keyboard of the typewriter used in the test. In the test of reaction time which took approximately 10 min. the subject was told to assume home position at the typewriter and to stroke as rapidly as possible the key beneath the finger being tested each time the stimulus light which was placed in copy position to his right illuminated. Initiation of the light was irregularly spaced so that no anticipated rhythm could be established. Ten reaction times were recorded for each of the eight fingers used on the alphabetic keyboard, beginning with the left little finger and ending with the right little finger, i.e., L4,L3, L2,L1, R1, R2, R3, R4. T o determine whether the reaction times among fingers differed, a repeated-measures analysis of variance was computed. Mean reaction time for each finger served as the dependent measure. Scheffi's multiple-comparison procedure was utilized to compare the mean performance for each finger and to compare the mean reaction times of the fingers on the left hand with the mean reaction times of the fingers on the right hand. An average inter-class correlation coefficient was computed to determine if the rank order of reaction times was consistent across fingers for individual typists. All data analyses were conducted using Statistical Package for the Social Sciences by Nie, Hull, Jenkins, Steinbrenner, and Bent (1975 ) .
RESULTS A summary of the results of the analysis of variance of reaction time among the fingers of the subjects which appears in Table 1 indicated a significant difference in reaction times among the fingers (F7,181 = 2.87, 9 < .01). Thus, the fingers differed in reaction time when averaged across subjects. A rank ordering of mean finger reaction times across subjects showed that the TABLE 1
ANALYSIS OF VARIANCE: SUMMARY OF FINGER-BY-FINGER REACTION T~.~Es* OF SKILLED TYPISTS TO VISUALCUE MEASURED AT THE TYPEWRITER WITH HANDS IN HOMEPOSITION Source
23 .2559 7 .0154 Error 161 .I241 Total 191 .3955 'Time recorded to nearest .001 sec. Subjects Fingers
.0111 .0022 .0007
.0001 .007 .
fingers with slowest to fastest reaction times were L4, L3, L1, L2, R1, R2, R3, R4, respectively. The Scheffe test was applied to the means which appear in Table 2. In comparing the mean response of each finger with the mean response of every other finger, a significant difference in mean response time was found for all fingers. The average reaction time for each finger was significantly different from the average reaction time of every other finger. Also, mean reaction time of the fingers on the left hand (M ,= .3159) was significantly slower than the mean reaction time of the fingers on the right hand (M = .3005). MEANSA N D STANDARD DBVIAT~ONS OF REACTIONTIME BY FINGER FOR 24 SKILLHDTYPISTS
R4 "L4 = left little finger, R4
.294 little finger.
An average inter-class correlation coefficient of .92 was obtained. This correlation indicates that if a person had a comparatively fast or slow reaction time on one finger, there mas a strong tendency to have similar reactions on the other fingers as well.
DISCUSSION Gatewood (1920) found differences in reaction times among the fingers, and Hoke (1922) found differences in the number of strokes which could be made in 30 sec. on a manual typewriter by each finger; however, neither study reported statistical analyses of those differences. The differences among the finger-by-finger reaction times of the subjects in this study were significant ( p = .007)and support the conclusion that reaction times of the fingers of the skilled typists in this study varied significantly when tested in typewriting position at the typewriter keyboard. The high inter-class correlation, however, indicated that there was a tendency for the rank order of reaction times of individual skilled typists to be similar across the fingers. It is not known what effect typewriting practice may have on reaction time of the fingers. In an earlier study Hayes, et al. ( 1977) found higher typewriting rate to be significantly correlated with lower difference between reaction times of the hands. If consistency among the
RT OF FINGERS IN TYPING
fingers is associated with rapid typewriting rates, longitudinal studies should be conducted to determine if consistency is present from the beginning or if it develops during the acquisition of the typewriting skill. The skilled typists in this study had significantly faster reaction times for the right hand than for the left. The conclusions of Gatewood (1920) and Hoke (1922) were similar, although their conclusions were not supported statistically. The ranking of fingers according to speed of response by Gatewood (1920) and the subjects in this study was similar. From slowest to fastest and using the numbering system for the fingers previously described in this study, Gatewood's ranking was L4, L2, L3, L1, R2, R3, R1, R4; the ranking of the subjects' fingers in this study was L4, L3, L1, L2, R1, R2, R3, R4. Gatewood tested half of her subjects beginning with the left little finger, moving across the hands and ending with the right little finger; the other half were tested in the opposite direction beginning with the right little finger and ending with the left little finger. All of the subjects in this study were tested beginning with the left little finger, moving across the hands and ending with the right little finger. Even though the order of testing was different in the two studies, the rankings were significantly similar as indicated by a Spearman's rank order correlation coefficient of .86 ( p = .01). REFERENCES D. H. Exercise physiology. Englewood Cliffs, N . J.: Prentice-Hall, 1975. CLARKE, CLARKE, D. H., & GLINES,D. Relationships of reaction, movement and completion
times to motor strength, anthropmetric and maturity measures of 13-year-old boys. Rerearch Quarterly, 1962, 33, 194. GATEWOOD, E. L. Individual differences in finger reactions. Psychological Monographs, 1920, 28, No. 126 (Whole No. 4 ) . HAYES, V., WILSON, G. D., & SCHAFER.R. L. Ty writing rate as a function of reaction tme. Pmeptuul and Motor Skillr, 1977, 1179-1184. HENRY, F. M., & ROGERS,E. E. Increased response latenq for complicated movements and a memory drum theory of neuromotor reaction. Research Qucrrtwly, 1960, 31, 448-458.
Horn, R. E Improvement of speed and accuracy in typewriting Johns Hopkins Studies in Education, 1922, No. 7.
LOITER,W . S. Interrelationships amon reaction times and speeds of movement in
1960, 31, 147-155. different limbs. Rerearch NIE, N . H., HULL,C H., JENK!NS, J. G., STEINBRBNNBR,K.,& BENT,D.H. Statirtical pakage for the socral screncer. (2nd ed.) New York: McGraw-Hill, 1975.
Accepted September 19, 1978.