Sixteen Experimental Investigations from the Harvard Psychological Laboratory - Hugo Münsterberg (best life changing books txt) 📗
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locality produces upon the interval in which it occurs. These two
factors may work in conjunction or in opposition, according to
conditions. The bare constant error does not remain exactly the same
at all times for any individual and is probably less regular in
tactual time than in auditory or in optical time, according to the
irregularity actually found and for reasons which will be assigned
later.
3. The third group of experiments introduced the factor of variation
in intensity of stimulation. By the introduction of a loop in the
circuit, containing a rheostat, two strengths of current and
consequently of stimulus intensity were obtained, either of which
could be employed as desired. One intensity, designated as W, was
just strong enough to be perceived distinctly. The other intensity,
designated as S, was somewhat stronger than the intensity used in
the preceding work.
In the first instance, sixty series were taken from Subject B, with
the conditions the same as in the experiments of Group 1, except that
two types of series were taken; the first two stimulations being
strong and the third one weak in the first type (SSW), and the order
being reversed in the second type (WSS). The results gave values of
ET of 5.27 secs. for SSW and 5.9 secs. for WSS.
In order to get comprehensive qualitative results as rapidly as
possible, a three-second standard was adopted in the succeeding work
and only one compared interval, also three seconds, was given,
although the subject was ignorant of that fact—the method being thus
similar to that adopted later for the final experiments of Group 2,
described above. Six types of tests were given, the order of
stimulation in the different types being SSS, WWW, SSW, WWS, SWW and
WSS, the subject always knowing which order to expect. For each of
the six types one hundred tests were made on one subject and one
hundred and five on another, in sets of five tests of each type, the
sets being taken in varied order, so that possible contrast effect
should be avoided. The results were practically the same, however, in
whatever order the sets were taken, no contrast effect being
discernible.
The total number of judgments of CT, longer, equal, and shorter, is
given in Table VIII. The experiments on each subject consumed a number
of experiment hours, scattered through several weeks, but the relative
proportions of judgments on different days was in both cases similar
to the total proportions.
TABLE VIII.
ST=CT= 3.0 SECS.
Subject R, 100. Subject P, 105.
L E S d L E S d
SSS 32 56 12 + 20 SSS 16 67 22 - 9
WWW 11 53 36 - 25 WWW 19 72 14 + 5
SSW 6 27 67 - 61 SSW 17 56 32 - 15
WWS 57 36 7 + 50 WWS 37 61 7 + 30
WSS 10 45 45 - 35 WSS 9 69 27 - 18
SWW 3 31 66 - 63 SWW 3 64 33 - 25
By the above table the absolute intensity of the stimulus is clearly
shown to be an important factor in determining the constant error of
judgment, since in both cases the change from SSS to WWW changed
the sign of the constant error, although in opposite directions. But
the effect of the relative intensity is more obscure. To discover more
readily whether the introduction of a stronger or weaker stimulation
promises a definite effect upon the estimation of the interval which
precedes or follows it, the results are so arranged in Table IX. that
reading downward in any pair shows the effect of a decrease in the
intensity of (1) the first, (2) the second, (3) the third, and (4) all
three stimulations.
TABLE IX.
Subject R. Subject P.
(1) SSS + 20 - 6
WSS - 35 - 55 - 18 - 12
SWW - 63 - 25
WWW - 25 - 38 + 5 + 30
(2) SSW - 61 - 15
SWW - 63 - 2 - 25 + 10
WSS - 35 - 18
WWS + 50 + 85 + 30 - 48
(3) SSS + 20 - 6
SSW - 61 - 81 - 15 - 7
WWS + 50 + 30
WWW - 25 - 75 + 5 - 25
(4) SSS + 20 - 6
WWW - 15 - 35 + 5 + 11
There seems at first sight to be no uniformity about these results.
Decreasing the first stimulation in the first case increases, in the
second case diminishes, the comparative length of the first interval.
We get a similar result in the decreasing of the second stimulation.
In the case of the third stimulation only does the decrease produce a
uniform result. If, however, we neglect the first pair of (3), we
observe that in the other cases the effect of a difference between
the two stimulations is to lengthen the interval which they limit. The
fact that both subjects make the same exception is, however, striking
and suggestive of doubt. These results were obtained in the first
year’s work, and to test their validity the experiment was repeated at
the beginning of the present year on three subjects, fifty series
being taken from each, with the results given in Table X.
TABLE X.
ST = 3.0 secs. = CT.
Subject Mm. Subject A. Subject D.
S E L d S E L d S E L d
SSS 24 13 13 - 11 7 30 13 + 6 10 31 9 - 1
WSS 33 9 8 - 25 20 24 6 - 14 17 27 6 - 11
SSW 19 15 16 - 3 23 16 11 - 12 10 31 9* - 1
WWW 19 12 19 0 13 26 11 - 2 1 40 9 + 8
SWW 18 30 2 - 16 23 21 6* - 17 7 38 5 - 2
WWS 13 16 21 + 8 12 30 8 - 4 15 25 10 - 5
*Transcriber’s Note: Original “16” changed to “6”, “19” to “9”.
Analysis of this table shows that in every case a difference between
the intensities of the first and second taps lengthens the first
interval in comparative estimation. In the case of subject Mm a
difference in the intensities of the second and third taps lengthens
the second interval subjectively. But in the cases of the other two
subjects the difference shortens the interval in varying degrees.
The intensity difference established for the purposes of these
experiments was not great, being less than that established for the
work on the first two subjects, and therefore the fact that these
results are less decided than those of the first work was not
unexpected. The results are, however, very clear, and show that the
lengthening effect of a difference in intensity of the stimulations
limiting an interval has its general application only to the first
interval, being sometimes reversed in the second. From the combined
results we find, further, that a uniform change in the intensity of
three stimulations is capable of reversing the direction of the
constant error, an intensity change in a given direction changing the
error from positive to negative for some subjects, and from negative
to positive for others.
III. INTERPRETATION OF RESULTS.
We may say provisionally that the change from a tactual stimulation
of one kind to a tactual stimulation of another kind tends to lengthen
subjectively the interval which the two limit. If we apply the same
generalization to the other sensorial realms, we discover that it
agrees with the general results obtained by Meumann[15] in
investigating the effects of intensity changes upon auditory time, and
also with the results obtained by Schumann[16] in investigations with
stimulations addressed alternately to one ear and to the other.
Meumann reports also that the change from stimulation of one sense to
stimulation of another subjectively lengthens the corresponding
interval.
[15] op. cit. (II.), S. 289-297.
[16] op. cit., S. 67.
What, then, are the factors, introduced by the change, which produce
this lengthening effect? The results of introspection on the part of
some of the subjects of our experiments furnish the clue which may
enable us to construct a working hypothesis.
Many of the subjects visualize a time line in the form of a curve. In
each case of this kind the introduction of a change, either in
intensity or location, if large enough to produce an effect on the
time estimation, produced a distortion on the part of the curve
corresponding to the interval affected. All of the subjects employed
in the experiments of Group 2 were distinctly conscious of the change
in attention from one point to another, as the two were stimulated
successively, and three of them, Hy, Hs and P, thought of
something passing from one point to the other, the representation
being described as partly muscular and partly visual. Subjects Mr
and B visualized the two hands, and consciously transferred the
attention from one part of the visual image to the other. Subject Mr
had a constant tendency to make eye movements in the direction of the
change. Subject P detected these eye movements a few times, but
subject B was never conscious of anything of the kind.
All of the subjects except R were conscious of more or less of a
strain, which varied during the intervals, and was by some felt to
be largely a tension of the chest and other muscles, while others felt
it rather indefinitely as a ‘strain of attention.’ The characteristics
of this tension feeling were almost always different in the second
interval from those in the first, the tension being usually felt to be
more constant in the second interval. In experiments of the third
group a higher degree of tension was felt in awaiting a light tap than
in awaiting a heavy one.
Evidently, in all these cases, the effect of a difference between
two stimulations was to introduce certain changes in sensation
during the interval which they limited, owing to the fact that the
subject expected the difference to occur. Thus in the third group of
experiments there were, very likely, in all cases changes from
sensations of high tension to sensations of lower, or vice versa. It
is probable that, in the experiments of the second group, there were
also changes in muscular sensations, partly those of eye muscles,
partly of chest and arm muscles, introduced by the change of attention
from one point to another. At any rate, it is certain that there were
certain sensation changes produced during the intervals by changes of
locality.
If, then, we assume that the introduction of additional sensation
change into an interval lengthens it, we are led to the conclusion
that psychological time (as distinguished from metaphysical,
mathematical, or transcendental time) is perceived simply as the
quantum of change in the sensation content. That this is a true
conclusion is seemingly supported by the fact that when we wish to
make our estimate correspond as closely as possible with external
measurements, we exclude from the content, to the best of our ability,
the general complex of external sensations, which vary with extreme
irregularity; and confine the attention to the more uniformly varying
bodily sensations. We perhaps go even further, and inhibit certain
bodily sensations, corresponding to activity of the more peripherally
located muscles, that the attention may be confined to certain others.
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