Sixteen Experimental Investigations from the Harvard Psychological Laboratory by Hugo Münsterberg (100 books to read .txt) 📕

6. 12.0 9.0 6.5 6.0 3.5 2.0 1.5 1.0

6.5 4.0 3.5 4.0 3.5 4.0 .5 0. 0.

No influence arising from practice is discoverable from this table,

and we may safely conclude that this hypothetical factor may be

disregarded, although among the experimenters on auditory time

Mehner[13] thought results gotten without a maximum of practice are

worthless, while Meumann[14] thinks that unpracticed and hence

unsophisticated subjects are most apt to give unbiased results, as

with more experience they tend to fall into ruts and exaggerate their

mistakes. The only stipulation we feel it necessary to make in this

connection is that the subject be given enough preliminary tests to

make him thoroughly familiar with the conditions of the experiment.

[13] op. cit., S. 558, S. 595.

[14] op. cit. (II.), S. 284.

2. The second group of experiments introduced the factor of a

difference between the stimulation marking the end of an interval and

that marking the beginning, in the form of a change in locality

stimulated, from one finger to the other, either on the same hand or

on the other hand. Two classes of series were given, in one of which

the change was introduced in the standard interval, and in the other

class in the compared interval.

In the first of these experiments, which are typical of the whole

group, both of the subject’s hands were employed, and a tapping

instrument was arranged above the middle finger of each, as above the

one hand in the preceding experiment, the distance between middle

fingers being fifteen inches. The taps were given either two on the

right hand and the third on the left, or one on the right and the

second and third on the left, the two orders being designated as RRL

and RLL respectively. The subject was always informed of the order

in which the stimulations were to be given, so that any element of

surprise which might arise from it was eliminated. Occasionally,

however, through a lapse of memory, the subject expected the wrong

order, in which case the disturbance caused by surprise was usually so

great as to prevent any estimation.

The two types of series were taken under as similar conditions as

possible, four (or in some cases five) tests being taken from each

series alternately. Other conditions were the same as in the preceding

work. The results for the six subjects employed are given in Table IV.

TABLE IV.

ST= 5.0 SECS. TWO HANDS. 15 INCHES.

Subject. Average RT. No. of Series.

RRL. RLL.* (Table II.)

Hs. 4.92 6.55 (5.26) 50

Sh. 5.29 5.28 (5.34) 50

Mr. 5.02 6.23 (5.25) 60

Mn. 5.71 6.71 (6.19) 24

A. 5.34 5.89 (5.75) 28

Sn. 5.62 6.43 (5.47) 60

*Transcriber’s Note: Original “RRL”

From Table IV. it is apparent at a glance that the new condition

involved introduces a marked change in the time judgment. Comparison

with Table II. shows that in the cases of all except Sh and Sn the

variation RRL shortens the standard subjectively, and that RLL

lengthens it; that is, a local change tends to lengthen the interval

in which it occurs. In the case of Sh neither introduces any change

of consequence, while in the case of Sn both values are higher than

we might expect, although the difference between them is in conformity

with the rest of the results shown in the table.

Another set of experiments was made on subject Mr, using taps on the

middle finger of the left hand and a spot on the forearm fifteen

inches from it; giving in one case two taps on the finger and the

third on the arm, and in the other one tap on the finger and the

second and third on the arm; designating the orders as FFA and FAA

respectively. Sixty series were taken, and the values found for the

average ET were 4.52 secs, for FFA and 6.24 secs, for FAA, ST

being 5.0 secs. This shows 0.5 sec. more difference than the

experiment with two hands.

Next, experiments were made on two subjects, with conditions the same

as in the work corresponding to Table IV., except that the distance

between the fingers stimulated was only five inches. The results of

this work are given in Table V.

TABLE V.

ST= 5.0 SECS. TWO HANDS. 5 INCHES.

Subject RRL. RLL. No. of Series.

Sh. 5.32 5.32 60

Hs. 4.40 6.80 60

It will be noticed that Hs shows a slightly wider divergence than

before, while Sh pursues the even tenor of his way as usual.

Series were next obtained by employing the first and second fingers on

one hand in exactly the same way as the middle fingers of the two

hands were previously employed, the orders of stimulation being 1, 1,

2, and 1, 2, 2. The results of sixty series on Subject Hs give the

values of average ET as 4.8 secs. for 1, 1, 2, and 6.23 sees, for 1,

2, 2, ST being 5.0 secs., showing less divergence than in the

preceding work.

These experiments were all made during the first year’s work. They

show that in most cases a change in the locality stimulated influences

the estimation of the time interval, but since the details of that

influence do not appear so definitely as might be desired, the ground

was gone over again in a little different way at the beginning of the

present year.

A somewhat more serviceable instrument for time measurements was

employed, consisting of a disc provided with four rows of sockets in

which pegs were inserted at appropriate angular intervals, so that

their contact with fixed levers during the revolution of the disc

closed an electric circuit at predetermined time intervals. The disc

was rotated at a uniform speed by an electric motor.

Experiments were made by stimulation of the following localities: (1)

First and third fingers of right hand; (2) first and second fingers of

right hand; (3) first fingers of both hands, close together, but just

escaping contact; (4) first fingers of both hands, fifteen inches

apart; (5) first fingers of both hands, thirty inches apart; (6) two

positions on middle finger of right hand, on same transverse line.

A standard of two seconds was adopted as being easier for the subject

and more expeditious, and since qualitative and not quantitative

results were desired, only one CT was used in each case, thus

permitting the investigation to cover in a number of weeks ground

which would otherwise have required a much longer period. The subjects

were, however, only informed that the objective variations were very

small, and not that they were in most cases zero. Tests of the two

types complementary to each other (e.g., RRL and RRL) were in

each case taken alternately in groups of five, as in previous work.

TABLE VI.

ST= 2.0 SECS.

Subject W.

(1) CT=2.0 (3) CT=2.2 (5) CT=2.0

113 133 RRL RLL RRL RLL

S 3 3 9 20 5 21

E 18 19 25 16 18 14

L 24 28 16 14 17 15

Subject P.

(1) CT=2.0 (3)CT={1.6 (5) CT={1.6

{2.4 {2.4

113 133 RRL(1.6) RLL(2.4) RRL(1.6) RLL(2.4)

S 2 16 12 16 15 10

E 38 32 32 21 26 19

L 10 2 6 15 14 21

Subject B.

(1) CT=2.0 (2) CT=2.0 (6) CT=2.0

113 133 112 122 aab abb

S 4 21 5 20 7 6

E 23 19 22 24 40 38

L 23 10 23 6 3 6

Subject Hy.

(1) CT=2.0 (2) CT=2.4 (1a) CT=2.0

113 133 112 122 113 133

S 12 46 17 40 17 31

E 9 2 14 8 9 7

L 29 2 19 2 14 2

In the series designated as (1a) the conditions were the same

as in (1), except that the subject abstracted as much as

possible from the tactual nature of the stimulations and the

position of the fingers. This was undertaken upon the

suggestion of the subject that it would be possible to perform

the abstraction, and was not repeated on any other subject.

The results are given in Table VI., where the numerals in the

headings indicate the localities and changes of stimulation, in

accordance with the preceding scheme, and ‘S’, ‘E’ and ‘L’

designate the number of judgments of shorter, equal and longer

respectively.

It will be observed that in several cases a CT was introduced in one

class which was different from the CT used in the other classes with

the same subject. This was not entirely arbitrary. It was found with

subject W, for example, that the use of CT = 2.0 in (3) produced

judgments of shorter almost entirely in both types. Therefore a CT

was found, by trial, which produced a diversity of judgments. The

comparison of the different classes is not so obvious under these

conditions as it otherwise would be, but is still possible.

The comparison gives results which at first appear quite irregular.

These are shown in Table VII. below, where the headings (1)—(3),

etc., indicate the classes compared, and in the lines beneath them

‘+’ indicates that the interval under consideration is estimated as

relatively greater (more overestimated or less underestimated) in the

second of the two classes than in the first,—indicating the opposite

effect. Results for the first interval are given in the line denoted

‘first,’ and for the second interval in the line denoted ‘second.’

Thus, the plus sign under (1)—(3) in the first line for subject P

indicates that the variation RLL caused the first interval to be

overestimated to a greater extent than did the variation 133.

TABLE VII.

SUBJECT P. SUBJECT W. SUBJECT B. SUBJECT Hy.

(1)—(3) (3)—(4) (1)—(3) (3)—(5) (2)—(1) (6)—(2) (2)—(1)

First. + - + - - + -

Sec. + + - + + + +

The comparisons of (6) and (2), and (1) and (3) confirm the

provisional deduction from Table IV., that the introduction of a

local change in an interval lengthens it subjectively, but the

comparisons of (3) and (5), (3) and (4), and (2) and (1) show

apparently that while the amount of the local change influences the

lengthening of the interval, it does not vary directly with this

latter in all cases, but inversely in the first interval and directly

in the second. This is in itself sufficient to demonstrate that the

chief factors of the influence of locality-change upon the time

interval are connected with the spatial localization of the areas

stimulated, but a further consideration strengthens the conclusion and

disposes of the apparent anomaly. It will be noticed that in general

the decrease in the comparative length of the first interval produced

by increasing the spatial change is less than the increase in the

comparative length of the second interval produced by a corresponding

change. In other words, the disparity between the results for the two

types of test is greater, the greater the spatial distance introduced.

The results seem to point to the existence of two distinct factors in

the so-called ‘constant error’ in these cases: first, what we may call

the bare constant error, or simply the constant error, which appears

when the conditions of stimulation are objectively the same as regards

both intervals, and which we must suppose to be present in all other

cases; and second, the particular lengthening effect which a change