Some Influences Which Affect the Rapidity of Voluntary Movements Author(s): F. B. Dresslar Reviewed work(s): Source: The American Journal of Psychology, Vol. 4, No. 4 (Aug., 1892), pp. 514-527 Published by: University of Illinois Press Stable URL: http://www.jstor.org/stable/1410800 . Accessed: 05/09/2012 04:39 Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at . http://www.jstor.org/page/info/about/policies/terms.jsp
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SOME: INFLUENCES WH1CH AFFE:CT TIIS RAPIDITY OF VOLIJNTARY DIOVEMEXTS.1 BYF. B. DRESSLAR, Fellow in Psychology in Clark Univer3ity.
The purpose of this researchWA8(1) to find a convenient and accuratemethod of recordingand timing rapid voluntary movements, and (2) to determine some of the conditions which infuence the rate of such movements. The experiments were limited to a study of the rate at which one can tap on a Morse key. Three hundred taps were made as rapidly as possible at each test, and the condition of the subject noted. During the course of the es:periments over 400 tests were made, involving more than 120,000 taps. SApparatus. The apparatus used consisted of a kymograph with the revolving drum set perpendicularly, and covered with smoked paper. On a standardwas fastened an electromagnet which was put in a circuit alternately made and broken by a clock. A ttached to the armatureof this magnet was a projectingmetal point which registered the seconds on the revolvingdrum. Onthe same standardwas fasteneda common clock movement, the escapementof which was alternately raised by an electro-magnetat one end, and by a resisting $pringat the other, accordingas the electric circuit was made or brokenby a ZIorsekey. Thus with each tap on the key the escapementwheel was permittedto move one notch. To prevent jars this key was placed on an adjacenttable, but near enough for the operator to managethe kymograph. Upon this key the taps recordedwere made. In order to register the taps on the slowly moving drumXa silk cord was passed once around a small pulley substituted for the second hand of the clock. One end of this cord was made fast to a wire bearing a fix:edwriting point, the other to a counterweight. The wire was held in a perpendicular position by passing it through two brass strips es:tending out from the 1 The work was doIle under the direction of Dr. Warren P. Lombard, Assistant Professor of Physiology, to whom I am iIldebted for many suggestions in determining methods for work, and for help in devising apparatus.
l
_
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|
I
515
VOLUNT A RY MOVEMENTS.
board on which the clock was fastened. The writing point was Ssed on the wire between these strips and the amplitude of its movementmade correspondexactly to 300 taps on the key, by adjusting a wooden clasp on the upper strip. When the drum was moving, the line traced by the writing point formed an angle with the abscissa which varied according to the rapidity of the taps on the key. To determinethe time requiredto make 300 taps, perpendiculars were drawn to the seconds line fromthe points where the writing point begall to rise and where it reached the upper limit of its motion. The seconds comprehendedbetween these perpendicularsgave the time. The following is an es:arapleof a normal record. @
_ _ _
__ a
I g
; |
|
|
| s
I l
i I
_X_ _-__ _i_
I I
| S li IZ
I | iw ig
a
E I
9 | |
| i |
fi
|
t
g.
|
I !
l
ax s|
C
9 1
l l 1
l
E
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_5
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__
FIG. 1.
k. From 8 a. m. to 6 p. m. sis tests of 300 Method of TVow taps each were made; one every two hours. The usual working hollrs of the day were thus covered hy the experiments, and sufflcienttime intervened between the records for the subject to recover from any possible fatigue. Three handred taps were chosen because it was thought that after practice this number would not be fatiguingl and at the lIt was noticed after the tests had all been made that many of the curves showed a decreasing rate towards the end of the 300 taps and thus gave evidence of incipient fatigue, though all sensations of fatigue had ceased with the first few days of the work. By actual count out of one hundred curves taken at random from the last month of work seventy showed the effiect of this unconscious fatigue. This strengthens the belief that the method used may prove useful as a mild but sensitive clinical test.
516
DRESSLAR:
sasmetime sufficiently greastto show asny fluctuation in the normal raste. The course of the experiments furnished no evidence thastthis numberwas not well chosen. 5:he fore-asrmrested on a firm support asnd the tappiIlg movements were ass fasrass possible confined to the wrist. Throughoutthese experiments the subject gave his whole asttention to the work, and masdethe 300 taspswith the greastest possible raspidity. The conditionof the operastorwasscasrefully recordedbeneastheaschrecord, asndespecial asttentiongiven to asnycircumstasncewhich it was thought might iniluence the rapidity of the tasps. lSormat rate of votuntary {aps. TasbleI, column 1, shows that the asveragerasteasttainedfor 300 taps for the time there recordedwas 8.5 taps per second. Column 2 should not be included in the average, because duringthis period many conditions were introducedthat more or less affectedthe normal rate. The most rapid rate attained for 300 taps for any single record was 10 taps per second. Even this last rate could be excelled for a short time. From 30 tests made at the beginningand near the end of the work, the rate for the left hand was found to be 5.3 taps per second.
517
VOLIJIirTitRYMOVSMEN>. 12ABLE
I.
1.
2. No. of seconds required to make 800 taps.
DATS.
8
A
Feb. 3 37 " 4 37
10
M
12 M
2
P
4
P
6P
DATE.
8
M
10 M 12 M
38
36
36
34.5 36
mar, 1044.29 87
38
33.5
3D.5
32.5 36
" ll 7
" 1243
6;
36
39
34
34.S
38
42
32.S 36
41
36
4l).23 36
" 1442
" 9 37
" 15
39
39
36.5 37
4P
38
" 6 40 36.S 34.S 36.26 34.S 34.S " 8 39.6 34 33.26 36 33.S 34.S 32.5 34
2P
0
40
43.25
42
39
46
34
43
38.S
34
33
" 1645
38
38.S 41
" 11 38
36.S 36.5 34.S 36
37
" 1742
39.5
40
41.76 30
s; 12
37.5 37
36
" 1843.S 40
4
0
37
38
40
36
38
40
36
42
" 10 39.76 37
4096
" 13 37
34.76 36
38
38.5 37.S 39.5 34.S 37
" 16 38.76 31.26 31.5 30
16 33.S " 17 36.5 33 ;;
18 36 " 19 39
4;
33
30.S 32
33.S 33.5 31.26 38.26
" 1939
37.S 36.S
" 2140.25 40
39
" 22
41
37.S 40
0
36.26 38
32.76 32
34
" 2345
38
39
37.26 37
39
36.26 36.S 37.S 33
33
" 24
43.76 41
40.S 38
8
34.S 33.S 37.26 32
36
" 295
47.5 37.25 41.26 36.S 37
" 20 37 36 " 22 40.7636
32
36
36.S 34.S 33
38.S 33 -
" 2640.5 40.5
40
" 2842.5 38.6 42.S
40
38.S 39
43
41
41.5
-
Aver. 37.8 36.4 34.6 36.o 33.S 36.1 General average 3a.3.
The rapidity with which the taps were made, at first suggested that the movements were not voluntary in the stricter sense, but more in the nature of tremor. To test this, the contacts of the Morse key producedby normal taps, were recorded on a revolving drum by a Deprbz signal, and each movement timed by a tuning fork of 100 V. D. These were comparedwith records taken in the same way for tremor of the wrist, and also of the fore-arm. A11attempts to produce tremor of the wrist resulted in lateral movements instead of the up and down movements used in makingthe regulartaps.
A' B
= a!
w
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!! ff!_
-
a _
_
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_
D1lESELAE:
518
This fact, together with the greater rapidity of the tained in both cases, seems to leave no doubt thattremor atmade were separatevoluntary the taps the contrast (A, B) between movements. Figure (2) shows the usual taps and tremor the fore-arm,and (A, B ) the usual taps and tremorof wrist. It will be seenbetween of the from tervals the subject could this figure that during short in the rate of the oscillations make 10.5 taps per second, while 12.2 per second, and for of the fore-arm during tremor was lateral tremor of the wrist second. 12.9 per A _ __
__
B'
7_
_i
!
_l FIG. 2.
Aand' = Voluntarytaps. BandB' = Tremor;B of forvarm,andB' of wrist.
519
VOLIJNTA1tYlWOVElKENS-. -
-Voluntaryhlovements. Time in hundredths of a second.
Tremor. Tlme in hundredthsof a second. -
L3u
Time.
No.
A
2 3 4 G 6
L'
9.8
B
9.2
..
9
.;
2
7.76 8.8
9.e
S
7.8
8.1
..
6
8.4
..
7
7.6
..
8
8.76
8.2
..
..
*
6
*
8
9.5 10
9.5 10
9.6
6.8
B'
8.9
6
8.S
4
3 4
8
..
10.S
3
No.
10*6
9.4
1
Time.
..
1@
T
A
Line.
'
3
8.3
4
7.8
5
7.5
6
8
7
6.7
8
8
9
8
Average. 10
Average.
7.9
DailE rhythm. After sis weeks of work it was seen t;hat the dally records indicated a daily rhythm and, when no varying influences were introduced, the records for lhe correspondinghours of each day were quite similar. The averages of the time required to make 300 hps at the different hours on t}le days given in Table I, columa 1, wereas follows: 2
DRESST.AR
520
TimeO£daY.
8 A.]l. 10A.M. 12M. 2P.M. 4P.}f.
Timein SeCOndE.37.8
36.6
38.6
36.5
33.5
6P.MI:. 35.1
The following characteristic curve is obtained from these averages. This curve would be much less significant did it not colTespond very closelJrin shape to the normal daily curve. B
.
|
35
8 A.X.
10 A.Y.
12 M.
2
r.X.
i
P.X.
6 P.X.
NOI!E.-Distance along the abscissae represents time of day; along the ordinates the number o! seconds required to make 300 taps.
The shape of this curve was une2rpected,for it wrasnaturally*ought that the greatest rapidity would be attained sometime during the forenoon. It will be shown later that the rate at wvhichit was possible to tap was increasedby mental excitement or activity, This fact is in harmonywith the dai]y rhythm. The activity of the central nervous system probably increased during the hours of work from 8 to 12, lessened during the noon hour of relawation,increased again until 4 o'clock in the afternoon,and then, the chief work of the day being over, again decreased. The close correspondence of this curve to the daily programmeof work for two years previous is suggestive in the direction of habit; these wrerespent in public school work with a daily programme beginning at 8 a. m. and closing at 4 p. m., with an hour and a half intermission at noon. It is probablealso, that correspondingchanges in the tonus of the muscles of the body, accompaniedtl}e changes of central activity, and this increased muscular tensiotl mechani-
521
VOLUNTARY MOVEMENTE.
cally favored the rapidit of the movements. The decreased rate at 2 p. m. cannot be accounted for by the walk to and from meals, as special experiments showed that the raX was not affected by such short walks. The rise at 6 p. m. may partly be due to fatigue, but it i# thought to be chiefly due to an uIl¢onsciousrelasation, as the chief work of the day ended at 4 p. m. By a careful study of the barometric charts extending over the wvholeseries of experiments, it was found that no efect of atmosphericpressure could be dete¢ted. Effect of Slascutar ESwercise.After almost two months of work it was noticed that irregularities were introducedinto the daily curve whena vigorous walk had been taken. To test this, walks were purposbly taken between different periods of work for a series of days; the follog {;ableshows the average results; these averages would be less gignificant,did not the sndirsdEl cases show every Ume a decreasedrate iter the walk: Before WalkEg. Time of Day.
8 a. m.
Time ia se¢. for 300
er
W*lking.
time ot Dag. Mm int >t°t
Difference.
41.75
10 a. m.
43.7B
2 sec.
10 a. m.
39
12 m.
43.5
4.5 "
12m.
36.6
ap. m.
44.S
8.5 "
2p.m.
39
4p.m.
44
6
;'
4p.m.
39
6p.m.
46
7
"
This falling ofl sa rate aStera walk is probablydue to (a) general fatigue and (b) mental relas:ation induced by the walk, because a walk toward the close of the day when the normal rate was the highest, produced more markedeflect than a similar walk in the morning. E.>ectof VtgorousMental Ewerctse. It wa8 noticed by a comparisonof records and the daily journal, that str¢ng mental concentration,especially if accompaniedwith the e2rcitement of interest, was favorableto rapidit.vof movement. To test this Eurther,records were taken immediatelybefore and after sorting into heaps as rapidly as possible 80 cards of 10 differentkinds. Several packs were rapidly distributed with a few seconds rest between, until st requiredthe utmost conwntratson to fi2:and keep 1he positson of the different kinds
522
DRESSLAR:
in mind. The esercise is somewhatexciting and to make the best time it requlres the most undivided attention. The following table gives the time in seconds required for making 300 taps before and after such experiments: Before Sorting Cards. Date
Time of Day.
*
Apr.
Time in sec. for300 taps.
5
3.00 p. m.
44
8
10.45 a. m.
8 "
After Sorting Cards. Time of Day.
Time in sec, tor 300 taps.
4.00 p. m.
41
-3
34.75
11.05 a. m.
38
+3*
5.05 p. m.
39.5
5.45 p. m.
39
9
8.10 a. m.
39
8.30 a. m.
36.5
-20
"
9
11.10 a. m.
39.25
12.00 m.
36.5
-2&
"
11
lO.lOa. m.
46
10.43
i;
11
3.40 p. m.
41
4.05
>" 12
4.00p.
39
4.4Sp.m.
"
13
10.35 a. m.
"
14
1.15 p.
;;
15
9.45
"
16
10.05 a. n.
i;
18
m.
a. m. p.
m.
i
40.7o
5*
41
0
36
-3
38.5
11.20 a. m.
38.5
m.
44.6
2.00 p. m.
39.5
-5
a. m.
41.7a
11.05
a. m,
41.6
-i
37.6
11.46
a. m.
34
-36
10.25a.m.
42.25
11.30 a. m.
36.6
0
523
VOLUNTARY MOVEhIENTH:
The sinlilarity of the curaresfor these figures is very striking, and they also show the markeddifferencein rate. .
,
.
..
.
.
,
I
l
Zi I
8
9
10
11
12
1
I.
I
2
F
8
li
4
,
6
|
i'
8
I
o
|
10
11
I i
,
12
1
11
2
1
1',
8
I
4
1l,
6
I
6
II.
Before Sorting Cards. After Sorting Cards. NOTE. Points a, b, c, d, etc. curve I, represent te3ts before sorting cards, and a', b', cts dt, etc., curve II corresponding tests after sorting cards. tRhe dotted line, A ', conllects the poiut3 representing the aserages before and after sorting the cards.
After studying the variations caused by such severe mental work, and taking into the account that vigorous physical e2rercise had produced the opposite effect, it seemed probable that the increase in rate was due to increased central activity and the unconscious tension of the muscles attending this central ez;citation. This view was somewhat strengthened, when a study of the whole series of ez;perimentsrevealed the fact that an increased rate had accompaniedmental ez;citement. For es:ample,the rate was increased after reading an interesting unes:pected letter, after the announcement of a distinguished visitor to inspect the work, and just before reading a paper before the psychological seminary. TVhile these observations are too few to base upon them definite statements, they are of value, because such conditions cannot be manufacturedat will. From the results of these observations the suggestion came that such infuences might throw light on the difierence be-
524
DRESSLAR:
tween sensory and motor reaction-time. The following table shows a series of reactions before and after sorting cards as previously explained, given in thousandths of a second and obtainedwith a Hipp chronoscope: Sensory.
Before
Carde.
Motor. After Cards.
128 131 215 131 130 197 165 147 181 14l 126 1t5. 129 116 133 13f; 154 138 134 214 139 ]21
161
123 134 146 151 148 114 129 140 161 143 107 123 137 lla 131 110
117 126 164 191 132 136 140 129 200 166 13.n 121
130 171 160 15t7
a 215 180 -
Ar.sar.19.1
117 103 116 111
151
181
Aver. 152.1
Before Cards
Aver. 139.3 -
116
After Cards.
au 131 121 116 117
119
115
123
117 107
104
118 115 126 142 158 122 130
140 136 232 149 108 117 115 130 131 156 121 12*3 107 126
110
109 103 100
118 108 109
115 121 104 114 129 107 111
146 98 119 116 ]26 113 113
Aver. 128.3
Aver. 118.6
Ar. rar. 15.5
Ar.rar.8.06
Ar.rar.16>.6
These differences in reaction-tirnes which are relative and not absolute must depend chiefly and primarily on changed central conditions; for even if, as has been suggested, the muscles are in a greater state of tension after such mental esercises, it is a result of an unconscious partial innervation of the muscles of the body accompanyiug illereased central activity. If it be true thati general muscular tension is produced by mental concentration, it leads to the very important suggestion, viz.: that the chief cause of the feeling of bodily
525
VOLUNTARY MOVEMENTS.
weariness resulting from mental concentration,may be due to muscularfatigue. Ewperimentson Othess. Bsperiments were made at my request by two other men. They followedthe sameprogramme that I had used. Records were taken for seventeen days by B., and for sis days by L. In neither case was there developed any marked daily rhythm. B.'s averages for the different hours, show the greatest rapidity at 8 a. m. and the least at 6 p. m., while the rate at the other four hours was approsimately the same. The mean variation is so large, however, that these averages are comparatively meaningless. The daily rhythm in my own case did not make its characteristic appearanceuntil aSteralmost a month7s practice. The only definite results from the work of B. and L. are their rates and the effect of e2ercise which will be spoken of further on B.'s rate for the whole series of tests made was 6.4 taps per second; for L. the rate was 6.8 taps per second. During the course of the experimentstests were madeupon a Ilumberof visitors. The accompanying table shows their rates?and is of interest in that great individual differences are shown. RATE OF VISITORS. TimP in sec. for 300 taps. Indind ual. Time of Day.
Date.
Time in sec. for 800 taps. , Date.
Right Hand.
I*ft Hand,
Individual. Time of Day. Right Hand.
1892 Feb. 5
A.
11.]0 a. m.
45
68
L.
2.30 p. m. 47
;'
4;
B.
11.30a. m.
46
49
" 12 M.
5.30p. m. 57
" ;'
C.
11.00 a. m.
42.5
61.5
" 12 No
5.30 p. m.
"
D.
6.00 p. m.
46
60
Apr. 4
" "
E.
9.00a. m.
44
67
*' 10
Po 12.00m.
" 9
F.
10.30 a. m.
45
60
'i 10
Q
l.OOp. m. 67
9
G.
4.00p. m.
46
54
" 10
R
1.00 p. mt 61.5
;' 9
EI. 4.10 p m.
49
4;
" 9
I.
4.1o p. m.
51.5
" 1o
" 22 J.
4.30 p. m.
52
4.00 p. m.
48
Mar.4
K.
189;! hIar.8
O.
1B S. T
Left Hand.
47.2a
10.00 a. m. 53 50
2.00 p. m. 66 2.00 p. m. 57
62
s
.
2
_
cw
O
_
_
DRESSLAR:
526
E,pct of Practice. The average rates of B. and L. were reached on the third day, and no perceptible increase came in the remainderof two weeka' work. The increased normal rate seemed to be chiefly due to the fact that fatigue ceased, which was showIl iIl the greater regularity of the curves. All visitors who took a recordfor the first time complained of fatigue, and the chaxlge in the directioIl of their curve toward the close of a recordplainly showed their diminishing rate. In my own case the average ability had been attai while testing and perfectingthe apparatusprevious to recording any work. II1order to test the effect of e2rerciseof the right hand UpOIlthe left, the rate of the left was found at the beginning of the experiment, and again, aiter more than two months of work. The result shows no gain in the left. If the rate of the left had been infuenced any it occurred before any records vere taken. P7.ect of Rest. The effect of a day of rest, when the subject was in good health, was very slight as shown by compar ing the records of two Saturdays sd two followingMondays: Saturdays. 0t
X
F
00
m2 e,!
w_2
X o
. >
Mondays. X cS
X vf
X co
43 41 36 40 36 40 39 37.536.5 40 36 38
0t
W
P;
00
8t s
l*!
M
X
o
X 4 Q
X
X
vf
e
42 43 38.t;43 40 43.25 40.5 40 39 40 36 42
From the above table it is seen that the control was slightly weakened for Mondays rather than strengthened; a marked differenceis shown between two Saturdays and the following Mondays, during a period of overwork, resulting in a week7S illness: Saturdays. SW
