Sixteen Experimental Investigations from the Harvard Psychological Laboratory - Hugo Münsterberg (best life changing books txt) 📗
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subject also showed no preference for objects. With the subjects S
and B the preference for actual movements is not marked, and has
importance only in the light of later experiments to be reported.
The great difference in the retentive power of different subjects is,
as we should expect, very evident. Roughly, they may be divided into
two groups. M and Mo recall much more than the other four. The
small percentage of recall in the case of these four suggested the
next change in the conditions of experimentation, namely, to shorten
with them the intervals between the tests for permanence. This was
accordingly done in the C set. But before giving an account of the
next set we may supplement these results by results obtained from
other subjects.
It was impossible to repeat this set with the same subjects, and
inconvenient, on account of the scarcity of suitable words, to devise
another set just like it. Accordingly, the B set was repeated with
six new subjects. We may interpolate the results here, and then resume
our experiments with the other subjects. The conditions remained the
same as for the other subjects in all respects except the following.
The tests after nine and sixteen days were omitted, and the remaining
test for deferred recall was given after one day instead of after two.
In learning the series, each series was shown four times instead of
three. The results are summarized in the following table. The figures
in the left half show the number of words out of sixteen which were
correctly recalled. The figures in parentheses separate, as before,
the correctly recalled indirect-association couplets. In the right
half of the table the same results, omitting indirect-association
couplets, are given in per cents, to facilitate comparison with the
summary from Tables I. and II.
TABLE III.
SHOWING RECALL AFTER ONE DAY.
N. O. V. M. N. O. V. M.
Bur. 6 10(1) 7(1) 5(4) 38 67 44 31
W. 5(3) 12(1) 6 9 31 75 38 56
Du. 1 11(1) 8 9 6 69 50 56
H. 9(1) 14 8 12 56 88 50 75
Da. 1(3) 7(4) 3(1) 9(3) 7 44 20 56
R. 7(2) 3(3) 5 5(1) 44 19 31 31
Total, 29(9) 57(10) 37(2) 49(8) Av., 30 60 39 51
Av. gain in object couplets, 30 per cent.
” ” ” movement couplets, 12 per cent.
The table shows that five subjects recall objects better than images
of objects, while one subject recalls images of objects better.
Similarly, three subjects recall actual movements of the body better
than images of the same, while with three neither type has any
advantage.
THE C SET.
In the C set certain conditions were different from the conditions
of the A and B sets. These changes will be described under three
heads: changes in the material; changes in the time conditions; and
changes in the method of presentation.
For lack of monosyllabic English words the verbs and movements were
dissyllabic words. The nouns and objects were monosyllabic, as before.
All were still concrete, and the movements, whether made or imaged,
were still simple. But the movements employed objects, instead of
being merely movements of the body.
For two of the subjects, M and Mo, the time intervals between the
tests remained as in the A and the B sets, namely, two days, nine
days, and sixteen days. With the four other subjects, S, Hu, B, and
Ho, the number of tests was reduced to three and the intervals were
as follows:
The I. test, which as before was a part of the learning process, was
not counted. The II. test followed from 4½ to 6½ hours, or an average
of 5-3/8 hours, after the I. test. The III. test was approximately 16
hours after the II. test for all four subjects.
The series were learned between 10 a.m. and 1:30 p.m., the II. test
was the same day between 4:30 and 5:10 p.m., and the III. test was the
following morning between 8:30 and 9:10 a.m. Each subject of course
came at the same hour each week.
Each series was shown three times, as in the B set.
A change had to be made in the length of exposure of each couplet in
the movement series. For, as a rule, movements employing objects
required a longer time to execute than mere movements of the body.
Five seconds was found to be a suitable length of exposure. To keep
the three other types of series comparable with the movement series,
if possible, their exposure was also increased from 3 to 5 secs. The
interval of 2 secs, at the end of a presentation was omitted, and the
interval between learning and testing reduced from 4 secs, in the B
set to 2 secs.
In the movement series of the A and B sets, movements of parts of
the body were chosen. But the number of such movements which a person
can conveniently make while reading words shown through an aperture is
limited, and as stated above no single word was ever used in two
couplets. These were now exhausted. In the C set, therefore,
movements employing objects were substituted. The objects lay on the
table in a row in front of the subject, occupying a space about 50 cm.
from left to right, and were covered by a black cambric cloth. They
were thus all exposed at the same moment by the subject who, at a
signal, laid back the cloth immediately before the series began, and
in the same manner covered them at the end of the third presentation.
Thus the objects were or might be all in view at once, and as a result
the subject usually formed a single mental image of the four objects.
With this kind of material it was no longer necessary for the operator
to show the subject in advance of the series what the movements were
in order to avoid hesitation and confusion, for the objects were of
such a nature as obviously to suggest in connection with the words the
proper movements.
TABLE IV.
SHOWING RECALL AFTER TWO, NINE AND SIXTEEN DAYS FOR TWO SUBJECTS, AND
AFTER FIVE HOURS AND TWENTY-ONE HOURS FOR FOUR OTHER SUBJECTS.
Days. Two. Nine. Sixteen Two. Nine. Sixteen
N. O. N. O. N. O. V. M. V. M. V. M.
Series M.
C^{1-4} 4 4 4 4 3 2 3 2 2 2 1 1
C^{5-8} 2 2 2 2 2 1 1 1 1 2 1 0
C^{9-12} 3 2 3 1 3 0 2 4 3 2 2 1
C^{13-16} 4 3(1) 4 2(1) 4 2(1) 3 4 2 3 2 3
Total 13 1(1) 13 9(1) 12 5(1) 9 11 8 9 6 5
Per cent. 81 73 81 60 75 33 56 69 50 56 38 31
Mo
C^{1-4} 2 4 1 1 1 1 1 4 1 2 1 2
C^{5-8} 3 2 4 1 3 1 4 3(1) 4 3(1) 2 2(1)
C^{9-12} 0 1 0 1 0 1 0 3 0 1 0 2
C^{13-16} 0 0(1) 0 0(1) 0 0(1) 1(1) 4 1(1) 2 0(1) 0
Total 5 7(1) 5 3(1) 4 3(1) 6(1) 14(1) 6(1) 8(1) 3(1) 6(1)
Per cent. 31 46 31 20 25 20 40 93 40 53 20 40
Hours. Five. Twenty-one. Five. Twenty-one
N. O. N. O. V. M. V. M.
Series S.
C^{1-4} 1 3 1 1 0 1 0 1
C^{5-8} 0(1) 3 0 2 0 1 0 1
C^{9-12} 0(1) 3 0(1) 4 3 4 3 4
C^{13-16} 1 3 1 3 2 3(1) 3 3(1)
Total 2(2) 12 2(1) 10 5 9(1) 6 9(1)
Per cent. 14 75 14 63 33 60 40 60
Hn.
C^{1-4} 1 4 1 4 0 4 1 4
C^{5-8} 0(2) 1 0(2) 1 0(1) 2 1(1) 2(2)
C^{9-12} 3 4 3 4 2 4 2 4
C^{13-16} 1 3 3 3 0 3(1) 0 2(1)
Total 5(2) 12 7(2) 12 2(1) 13(3) 4(1) 12(3)
Per cent. 36 75 50 75 14 100 29 92
B.
C^{1-4} 3 4 3 4 3 4 3 4
C^{5-8} 3 2 3 3 2 2 2 4
C^{9-12} 2 4 2 3 2 1 2 2
C^{13-16} 3 4 3 4 2 4 2 4
Total 11 14 11 14 9 11 9 14
Per cent. 69 88 69 88 56 69 56 88
Ho.
C^{1-4} 3(1) 2(2) 3(1) 2(2) 0 3(1) 0 1(1)
C^{5-8} 3(1) 4 3(1) 4 3 3(1) 3 3(1)
C^{9-12} 1(2) 4 1(2) 4 2(1) 3(1) 2(1) 3(1)
C^{13-16} 0 2 0 2 2 4 2 4
Total 7(4) 12(2) 7(4) 12(2) 7(1) 13(3) 7(1) 11(3)
Per cent. 58 92 58 92 50 100 50 85
The object series were also changed to conform to the movement series.
Formerly the objects had been shown successively through the aperture
and synchronously with their corresponding words; now they were on the
table in front of the subject and all uncovered and covered at once as
in the movement series. The subjects therefore had a single mental
image of these four objects also.
In both the object and the movement series the objects as before were
small and fairly uniform in size and so selected as not to betray to
the subject their presence beneath the cloth in the I. test. In the
II., III. and IV. tests there were no objects on the table.
The previous table shows the results of the C set. The figures give
the number of couplets correct out of four; the figures in brackets
give the number of indirect associations; the total number recalled in
any series is their sum.
In the following summary the recall of M and Mo after two days and
of S, Hu, B and Ho after twenty-one hours are combined.
SUMMARY FROM TABLE IV.
N. O. V. M.
M. 81 per cent. 73 per cent. 56 per cent. 69 per cent.
Mo. 31 ” 46 ” 40 ” 93 “
S. 14 ” 63 ” 40 ” 60 “
Hu. 50 ” 75 ” 29 ” 92 “
B. 69 ” 88 ” 56 ” 88 “
Ho. 58 ” 92 ” 50 ” 85 “
–––— –––— –––— –––—
Av. 51 per cent. 73 per cent. 45 per cent. 81 per cent.
Av. gain in object couplets, 22 per cent.
” ” ” movement couplets, 36 per cent.
Before asking whether the results of the C set confirm the
conclusions already reached, we must compare the conditions of the
three sets to see whether the changes in the conditions in the C set
have rendered it incomparable with the other two. The first change was
the substitution of dissyllabic words in the verb and the movement
series in the place of monosyllabic words. Since the change was made
in both the verb and the movement series their comparability with each
other is not interfered with, and this is the point at issue.
Preliminary tests, however, made it highly probable that simple
concrete dissyllabic words are not more difficult than monosyllabic in
5 secs. exposure. This change is therefore disregarded.
The first important change introduced in the C set was the reduction
of the intervals between the tests for four subjects. The second was
the lengthening of the exposure from 3 to 5 secs. These changes also
do not lessen the comparability of the noun, object, verb and movement
series with one another,
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