Report on Reaction.

Reaction tests with the group of University students were conducted in essentially the same way as were the reaction tests with the soldiers. Details in regard to the method and apparatus employed need not be repeated. They can be found on [pages 274 to 276].

Two new tests were added to the regular reaction determinations. One of these consisted in taking a record of the number of taps which could be executed in ten seconds. The reactor was seated before a table on which was fastened a telegraph key. He held the key between his thumb and first two fingers, and at a given signal began tapping as rapidly as possible until told to stop. Each time he tapped he closed an electric circuit. The current thus made was carried through a marker which indicated on a smoked paper each make and break at the key. A time line from a rod vibrating at the rate of once every twentieth of a second was traced on the smoked paper parallel with the marker record. By a comparison of the time line with the marker record, it was easy to determine the number of taps made in ten seconds. At first, the number of taps per second were counted, but the results showed such uniformity from second to second on a given day that only the net results for the whole ten seconds are given in the tables.

W. L. ANDERSON BELLIS

Photographs taken prior to the experiment.

The second test added to the reaction tests was undertaken to determine the steadiness of the subjects. Two brass rods 40 cm. long were held in a vertical position at a distance of 7 mm. from each other. The subject took in his right hand a brass rod 40 cm. long and 5 mm. in diameter and tried to pass the end of this rod up and down between the vertical rods without touching them. The subject’s relation to the vertical rods may be further defined by saying that he stood directly in front of them and reached out nearly at arm’s length. The vertical rods were at about the height of his chest. In order to get a record of the accuracy with which the subject moved the hand-rod up and down without touching the vertical rods, the vertical rods and the hand-rod were connected with the two poles of an electric circuit. Whenever they touched they closed the circuit, and a marker placed in the same circuit recorded the fact on a smoked paper record. The time was recorded in parallel with this record, so that any long continued contact could be measured. For the most part, contacts were only of very brief duration. In reporting the results of this test, every contact made while passing the rod once downward and once upward is counted as at least one. Continued contacts are recorded as two, three or more, according to the period of duration. Where there are such added counts because of continued contacts, a second quantity is given in the tables after the first. This second quantity, which is enclosed in parenthesis, indicates merely the number of contacts without reference to whether they are long or short.

No special comments are necessary to explain the tables. Tables 1-5 report in sigmas, or thousandths of a second, the average time of ten reactions on the date, and for the subject, indicated. In the third column, is the mean variation for the series of ten reactions.

Table 6 shows the general averages by the month for a given individual, and in the sixth column the general average of all the determinations for each reactor. The fourth column in each of the earlier tables shows how much the results of a given day vary from the final general average. All the tables give, at the bottom, group averages whenever the full series is present.

Table 7 gives the number of taps executed in ten seconds at each successive test. The dates are not given in detail, but are the same as those of the reaction tests.

Table 8 gives the monthly averages of taps.

Table 9 presents the results of the steadiness tests.

The three sets of results, namely, those from reaction, tapping, and steadiness, differ from each other. On the whole, the reactions grow longer; the tapping varies, but shows neither decided improvement nor deterioration; while steadiness improves very decidedly.

The comment made on the results obtained with the soldiers applies here so far as the reaction tests are concerned. These tests were not repeated with sufficient frequency to reduce the reaction to automatic performance.

The tapping is such a simple performance that improvement is not to be expected. The absence of any general improvement or deterioration argues for an absence of any general nervous change in the reactors.

The improvement in steadiness is in part at least, probably in very large measure, due to the fact that the subjects became more familiar with the test and approached it with less of the embarrassment which attends a new and unfamiliar test.

The lengthening of the reaction times indicates a less intense concentration of the subject upon the work in hand. The slightest relaxation of attention puts the subject behind in responding to the signal. It was clear to superficial observation, especially in certain individual cases, that the subject was giving less attention in the later experiments. This lack of concentration is not obviously related to the changes in diet. Indeed, the fact that no corresponding falling off appears in the tapping would seem to argue that the lack of attention in the reaction tests was not due to deep-seated nervous conditions, so much as to growing impatience on the part of the reactors with the ordeal of being tested. The tapping experiment is less likely to be affected by lack of interest on the part of the subject, because here the subject is called upon to be constantly active, and there is no such opportunity for attention to lapse as is furnished by the intervals which intervene between successive reactions. The tapping is accordingly perhaps the best series on which to base final judgment as to the nervous condition of the men. Here, there appear the variations which show in any ordinary series, but there is no steady improvement through growing familiarity with the test, nor any laxness of attention to produce relatively unfavorable results.

Mr. Steele and Dr. McAllister are largely responsible for the actual collection of the data on which this report is based.

(Signed) C. H. Judd.

TABLE 1.—February, 1904.

Name.		Date	Avg.	M.V.	Var. from G.A.	Date	Avg.	M.V.	Var. from G.A.
I.	Anderson, G. W.	19	153.5	13.8	31.4	26	192.2	19.4	7.3
II.	Anderson, W. L.	18	261.0	82.5	32.5	27	293.6	71.0	65.1
III.	Bellis	16	189.3	40.0	8.2	26	182.3	18.5	0.5
IV.	Donahue	17	173.6	43.0	28.4	24	182.7	14.5	19.3
V.	Jacobus	17	197.3	14.7	27.6	24	178.2	18.3	46.7
VI.	Schenker	17	162.3	29.7	67.6	24	209.8	46.6	20.1
VII.	Stapleton	19	185.1	31.6	23.9
Group averages			188.8
VIII.	Callahan[*]	18	156.2	10.4	37.0	25	210.8	27.2	17.6

[*] Kept separate because series of tests is not complete.

TABLE 2.—March, 1904.

Name.		Date	Avg.	M.V.	Var. from G.A.	Date	Avg.	M.V.	Var. from G.A.	Date	Avg.	M.V.	Var. from G.A.	Date	Avg.	M.V.	Var. from G.A.
I.	Anderson G. W.					11	181.6	38.3	3.3	18	181.3	25.1	3.6	26	170.5	26.1	14.4
II.	Anderson, W. L.	8	235.4	50.4	69.0	10	207.3	32.2	21.2	17	189.3	41.3	39.2
III.	Bellis	8	174.0	44.4	7.8	15	180.8	21.8	1.0	22	193.5	16.5	11.7	29	181.0	8.5	0.8
IV.	Donahue	2	201.6	24.8	0.4	9	214.7	29.3	12.7	23	224.9	53.7	22.9
V.	Jacobus	2	207.5	14.4	17.4	9	189.9	11.9	35.0	16	239.6	41.0	14.7	23	196.7	27.2	28.2
VI.	Schenker	2	283.5	98.0	53.6	9	296.9	74.9	67.0	16	281.9	80.8	52.9
VII.	Stapleton	4	211.1	41.7	2.1	11	205.4	14.6	3.6
Group averages							210.9
VIII.	Callahan	3	202.0	23.9	8.8	10	197.0	29.0	3.8	17	200.9	23.0	7.7	24	179.9	20.6	13.3

TABLE 3.—April, 1904.

Name.		Date	Avg.	M.V.	Var. from G.A.	Date	Avg.	M.V.	Var. from G.A.
I.	Anderson, G. W.	22	202.8	10.6	17.9	29	182.9	6.7	2.0
II.	Anderson, W. L.					29	195.0	20.3	33.5
III.	Bellis	19	193.0	27.2	11.2	26	182.5	18.2	0.7
IV.	Donahue	20	198.4	7.0	3.6	27	191.6	37.6	10.4
V.	Jacobus	20	253.1	70.7	28.2	27	221.3	14.7	3.6
VI.	Schenker	21	229.4	33.0	0.5	28	250.1	78.3	20.2
VII.	Stapleton					29	217.1	30.5	8.1
Group averages							205.8
VIII.	Callahan	21	205.5	12.5	12.3

TABLE 4.—May, 1904.

Name.		Date	Avg.	M.V.	Var. from G.A.	Date	Avg.	M.V.	Var. from G.A.	Date	Avg.	M.V.	Var. from G.A.	Date	Avg.	M.V.	Var. from G.A.
I.	Anderson, G. W.					13	181.2	16.5	3.7	20	199.6	8.2	14.7	27	190.7	12.1	5.8
II.	Anderson, W. L.					10	202.1	12.1	26.4					24	246.4	34.9	17.9
III.	Bellis					10	185.5	19.4	3.7	18	185.8	3.4	4.0	24	171.3	10.3	10.5
IV.	Donahue									18	217.2	18.0	15.2	25	207.1	19.5	5.1
V.	Jacobus	4	240.6	42.4	15.7	11	234.2	40.0	9.3	18	235.5	39.6	10.6	25	245.4	29.7	20.5
VI.	Schenker	5	214.3	24.0	15.6					19	234.3	40.5	4.4	26	196.9	16.9	33.0
VII.	Stapleton					11	224.4	15.9	15.4	18	201.1	11.7	7.9	25	217.8	16.5	8.8
Group averages															210.8

TABLE 5.—June, 1904.

Name.		Date	Avg.	M.V.	Var. from G.A.
I.	Anderson, G. W.	3	197.4	16.8	12.5
II.	Anderson, W. L.	7	226.8	20.3	1.7
III.	Bellis	7	162.0	8.4	19.8
IV.	Donahue	1	208.4	31.7	6.4
V.	Jacobus	1	284.6	45.6	59.7
VI.	Schenker	3	228.6	43.3	1.3
VII.	Stapleton	7	210.4	34.2	1.4
Group averages			216.9

TABLE 6.

Name.		February.	March.	April.	May.	June.	General Avg. of all Tests.
Name.		Avg. of all Tests for the Month.					General Avg. of all Tests.
I.	Anderson, G. W.	177.9	177.8	192.9	190.5	197.4	184.9
II.	Anderson, W. L.	277.3	210.7	195.0	224.3	226.8	228.5
III.	Bellis	185.8	182.3	187.8	178.5	162.0	181.8
IV.	Donahue	178.1	213.4	195.0	212.2	208.4	202.0
V.	Jacobus	187.8	208.4	237.2	238.9	284.6	224.9
VI.	Schenker	186.1	200.7	239.8	215.2	228.6	229.9
VII.	Stapleton	185.0	208.3	217.1	214.4	210.4	209.0
Monthly averages		196.8	200.2	209.3	210.6	216.9
VIII.	Callahan	183.5	194.9	205.5			193.2

TABLE 7.

Name.		February.		March.				April.		May.				June.
Name.		No. of taps in 10 sec.
I.	Anderson, G. W.	88	78		64	76	72	78	72		78	71	72	76	75.0
II.	Anderson, W. L.	81	86	76	84	77			83		78		85	78	80.9
III.	Bellis	84	90	78	78	80	76	78	69		80	78	67	72	78.0
IV.	Donahue	80	89	81	83	85		86	85			90	86	88	85.3
V.	Jacobus	70	82	75	77	72	76	77	78	75	90	75	80	74	77.3
VI.	Schenker	62	65	70	64	64		66	63	67		66	70	65	65.6
VII.	Stapleton	87		68	71				77		81	79	77	74	77.1
Group averages		78.8			74.4				75.3				76.7	75.4
VIII.	Callahan	82	75	89	83	78	88	86							83

TABLE 8.

Name.		February.	March.	April.	May.	June.
Name.		Avg. of all Determinations for the Month.
I.	Anderson, G. W.	83	71	75	74	76
II.	Anderson, W. L.	84	79	83	81	78
III.	Bellis	87	78	69	74	72
IV.	Donahue	85	83	85	90	88
V.	Jacobus	76	74	78	80	74
VI.	Schenker	64	66	65	69	74
VII.	Stapleton	87	70	79	78	74
Monthly averages		81	74	76	81	75
VIII.	Callahan	79	85	86

TABLE 9.

Name.		February.		March.				April.		May.				June.
Name.		Date.		Date.		Date.		Date.		Date.		Date.		Date.
I.	Anderson, G. W.	19	34 (28)	11	27 (23)	26	20 (17)	29	20 (15)	20	15 (13)			3	5
II.	Anderson, W. L.	27	48 (37)	10	72 (59)	17	49 (41)			10	26 (19)			7	12 (9)
III.	Bellis	16	57 (43)	8	43 (37)	29	30 (24)	26	40 (24)	18	23 (18)			7	16 (12)
IV.	Donahue	17	45 (40)	2	27 (21)	23	35 (30)	27	24 (22)	25	18 (16)			1	9
V.	Jacobus	17	37 (30)	9	76 (63)	16	35 (31)	20	24 (20)	11	27 (18)	25	20 (15)	1	18 (14)
VI.	Schenker	17	75 (66)	9	67 (58)			21	63 (54)	19	45 (39)			3	30 (24)
VII.	Stapleton	19	44 (33)	11	32 (26)			29	30 (22)	16	11 (10)			7	0
VIII.	Callahan	18	29 (26)	17	24 (20)