Various - Harvard Psychological Studies, Volume 1

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The verbs were similar to the verbs of the couplet series. There was a
tendency in the verb series among most of the subjects to make a more
or less connected story of the verbs and thus some subjects could
retain all ten words for two days. This was an element not present in
the couplet verb series, according to the subjects, nor in any other
series, and the subjects were, therefore, directed to eliminate it by
imaging each action in a different place and connected with different
persons. The effort was nearly successful, some of the subjects
connecting two or three verbs, and others none. The movements employed
ten objects which were uncovered and covered by the subject as in the
_C_ set. The exposure for the verbs and movements was 5 secs. for each
word, or 50 secs. for the series. The tests were the same as in the
series of ten nouns and ten objects, but in a number of cases (to be
specified in the table) it seemed best to shorten the interval for
deferred recall to one day.

The series were always given in pairs--a noun and an object series, or
a verb and a movement series forming a pair. Only one pair was given
per day and no other series of any kind were given on that day.
Usually several days intervened between the II. test of one pair and
the learning of the next, but in a little less than half of the cases
a new pair was learned on the same day shortly after the II. test of
the preceding pair.

The noun-object pairs and the verb-movement pairs were not given in
any definite order with reference to each other.

The figures in the following table indicate the number of words out of
ten which the subject correctly recalled and placed in their proper
columns. Immediate recall is also given.

TABLE VII.

Series. Im. Rec. Two Days. Im. Rec. Two Days.
N. O. N. O. V. M. V. M.

_M._
D^{1-4} 8 9 7 7 7 10 4 5
D^{5-8} 9 7 6 6 8 8 6 6
D^{9-12} 7 7 5 6 8 10 7 7
Av. 24 23 18 19 23 28 17 17

_Mo_.
D^{1-4} 6 6 2 1 8 10 0¹ 7¹
D^{5-8} 6 5 0¹ 3¹ 8 9 2 4
D^{9-12} 5 7 1¹ 6¹ 10 10 2 7
Av. 17 18 3 10 26 29 4 18

_S_.
D^{1-4} 8 9 2 3 9 10 6¹ 9¹
D^{5-8} 8 10 2 4 9 10 4¹ 9¹
D^{9-12} 8 10 2 5 8 10 3¹ 7¹
Av. 24 29 6 12 26 30 13 25

_Hu._
D^{1-4} 6 8 3 7 9 10 4 9
D^{5-8} 7 9 0 2 9 10 2 7
D^{9-12} 7 9 4 6 8 10 1 8
Av. 20 26 7 15 26 30 7 24

_Ho._
D^{1-4} 9 9 3 3 10 9 5 7
D^{5-8} 9 8 1 6 9 9 6¹ 8¹
D^{9-12} 8 8 5 5 10 10 6¹ 7¹
Av. 26 25 9 14 29 28 17 22

¹ One day.

The results of the _D_ set strongly confirm the results of the _A_,
_B_, and _C_ sets. Table VII. shows that after from one to two days'
interval four subjects recall objects better than nouns and movements
better than verbs. One subject, _M._, shows no preference.

CONCLUSIONS.

We are now in a position to answer specifically the problem of this
investigation. The results show: (1) that those five subjects who
recall objects better than nouns (involving images) _when each occurs
alone_, also recall objects better than nouns when each is recalled by
means of an unfamiliar verbal symbol with which it has been coupled;
(2) that the same is true of verbs and movements; (3) that these facts
also receive confirmation on the negative side, viz.: the one subject
who does not recall objects and movements better than nouns and verbs
(involving images) _when they are used alone_, also does not recall
them better _when they are recalled by means of foreign symbols_ with
which they have been coupled.

MINOR QUESTIONS.

The problem proposed at the outset of the investigation having been
answered, two minor questions remain: (1) as to images, (2) indirect
associations.

1. All the subjects were good visualizers. The images became clear
usually during the first of the three presentations, _i.e._, in 1-3
secs., and persisted until the next couplet appeared. In the second
and third presentations the same images recurred, rarely a new one
appeared.

An interesting side light is thrown on M.'s memory by his work in
another experiment in which he was a subject. This experiment required
that the subject look at an object for 10 secs. and then after the
disappearance of its after-image manipulate the memory image. M.
showed unusually persistent after-images. The memory images which
followed were unusually clear in details and also persistent. They
were moreover retained for weeks, as was shown by his surprising
ability to recall the details of an image long past, and separated
from the present one by many subsequent images. His memory was
capacious rather than selective. His eyesight was tested and found to
be normal for the range of the apparatus. Possibly his age (55 yrs.)
is significant, although one of the two subjects who showed the
greatest preference for objects and movements, Mo., was only six yrs.
younger. The ages of the other subjects were S. 36 yrs., Hu. 23 yrs.,
B. 25 yrs., Ho. 27 yrs.

That some if not all of the subjects did not have objective images in
many of the noun and verb couplets if they were left to their own
initiative to obtain them is evident from the image records in the _A_
set, in which the presence of the objective images was optional but
the record obligatory. The same subject might have in one noun or verb
series no visual images and in another he might have one for every
couplet of the series. After the completion of the _A_ set, the effect
of the presence of the objective images in series of 10 nouns alone,
or 10 objects alone after two days' interval, was tested. This was
merely a repetition of similar work by Kirkpatrick after three days'
interval, and yielded similar results. As a matter of fact some of the
subjects were unable wholly to exclude the objective images, but were
compelled to admit and then suppress them as far as possible, so that
it is really a question of degree of prominence and duration of the
images.

The presence of the objective images having been shown to be an aid in
the case of series of nouns, the subjects were henceforth requested to
obtain them in the noun and verb series of the _B_ and _C_ sets, and
the image records show that they were entirely successful in doing so.

2. The total number of couplets in any one or in several sets may be
divided into two classes: (1) Those in which indirect associations did
not occur in the learning, and (2) those in which they did occur. For
reasons already named we may call the first pure material and the
second mixed. We can then ascertain in each the proportion of
correctly recalled couplets after one, two, nine and sixteen days'
interval, and thus see the importance of indirect associations as a
factor in recall. This is what has been done in the following table.

The figures give the number of couplets correctly or incorrectly
recalled out of 64. In the case of the interval of one day the figures
are a tabulation of the III. test (twenty-one hours) of the _C_ set,
which contained 16 series of 4 couplets each. The figures for the
intervals of two, nine and sixteen days are a tabulation of the _B_
set, which also contained 16 series of 4 couplets each. _C_ denotes
correct, _I_ incorrect.

TABLE VIII.

SHOWING GREATER PERMANENCE OF COUPLETS IN WHICH INDIRECT ASSOCIATIONS
OCCURRED.

Pure Material. Mixed Material.
Days. One. Two. Nine. Sixteen. One. Two. Nine. Sixteen.
C I C I C I C I C I C I C I C I
_M._ 40 22 23 39 22 40 2 0 2 0 3 0
_Mo._ 36 22 31 27 29 29 6 0 6 0 5 1
_S._ 27 34 6 55 2 59 1 60 2 1 3 0 3 0 3 0
_Hu._ 35 22 16 45 5 56 4 57 6 1 3 0 3 0 3 0
_B._ 48 16 17 43 9 51 7 53 0 0 4 0 1 3 1 3
_Ho._ 37 15 17 30 13 36 3 46 10 2 9 6 8 7 7 8

Total: 147 87 132 217 83 268 66 285 18 4 27 6 23 10 21 12
P'c't.: 63 37 38 62 24 76 19 81 82 18 82 18 70 30 64 36

We see from the table that the likelihood of recalling couplets in
which indirect associations did not occur in learning is 63 per cent.
after one day, and that there is a diminution of 44 per cent. in the
next fifteen days. The fall is greatest during the second day. On the
other hand, the likelihood of recalling couplets in which indirect
associations did occur is 82 per cent. after one day, and there is a
diminution of only 18 per cent. during the next fifteen days. The
fading is also much more gradual.

It is evident, then, that in all investigations dealing with language
material the factor of indirect associations--a largely accidental
factor affecting varying amounts of the total material (in these six
subjects from 3 per cent. to 23 per cent.) is by far the most
influential of all the factors, and any investigations which have
heretofore failed to isolate it are not conclusive as to other
factors.

The practical value of the foregoing investigation will be found in
its bearing upon the acquisition of language. While it is by no means
confined to the acquisition of the vocabulary of a _foreign_ language,
but is also applicable to the acquisition of the vocabulary of the
native language, it is the former bearing which is perhaps more
obvious. If it is important that one become able as speedily as
possible to grasp the meaning of foreign words, the results of the
foregoing investigation indicate the method one should adopt.

* * * * *

MUTUAL INHIBITION OF MEMORY IMAGES.

BY FREDERICK MEAKIN.

The results here presented are the record of a preliminary inquiry
rather than a definitive statement of principles.

The effort to construct a satisfactory theory of inhibition has given
rise, in recent years, to a good deal of discussion. Ever since it was
discovered that the reflexes of the spinal cord are normally modified
or restrained by the activity of the brain and Setschenow (1863)
attempted to prove the existence of localized inhibition centers, the
need of such a theory has been felt. The discussion, however, has been
mainly physiological, and we cannot undertake to follow it here. The
psychologist may not be indifferent, of course, to any comprehensive
theory of nervous action. He works, indeed, under a general
presumption which takes for granted a constant and definite relation
between psychical and cerebral processes. But pending the settlement
of the physiological question he may still continue with the study of
facts to which general expression may be given under some theory of
psychical inhibition not inconsistent with the findings of the
physiologist.

A question of definition, however, confronts us here. Can we, it may
be asked, speak of psychical inhibition at all? Does one conscious
state exercise pressure on another, either to induce it, or to expel
it from the field? 'Force' and 'pressure,' however pertinent to
physical inquiries, are surely out of place in an investigation of the
relations between the phenomena of mind. Plainly a distinction has to
be made if we are to carry over the concept of inhibition from the
domain of nervous activity to the conscious domain. Inhibition cannot,
it should seem, have the same sense in both. We find, accordingly,
that Baldwin, who defines nervous inhibition as 'interference with the
normal result of a nervous excitement by an opposing force,' says of
mental inhibition that it 'exists in so far as the occurrence of a
mental process prevents the simultaneous occurrence of other mental
processes which might otherwise take place.'[1]

[1] Baldwin, J.M.: 'Dictionary of Philosophy and Psychology,'
New York and London, 1901, Vol. I., article on 'Inhibition.'

Even here, it may be said, there is in the term 'prevents' an
implication of the direct exercise of force. But if we abstract from
any such implication, and conceive of such force as the term
inhibition seems to connote, as restricted to the associated neural or
physiological processes, no unwarranted assumptions need be imported
by the term into the facts, and the definition may, perhaps, suffice.

Some careful work has been done in the general field of psychical
inhibition. In fact, the question of inhibition could hardly be
avoided in any inquiry concerning attention or volition. A. Binet[2]
reports certain experiments in regard to the rivalry of conscious
states. But the states considered were more properly those of
attention and volition than of mere ideation. And the same author
reports later[3] examples of antagonism between images and sensations,
showing how the latter may be affected, and in some respects
inhibited, by the former. But this is inhibition of sensations rather
than of ideas. Again, Binet, in collaboration with Victor Henri,[4]
reports certain inhibitory effects produced in the phenomena of
speech. But here again the material studied was volitional. More
recently, G. Heymans[5] has made elaborate investigation of a certain
phase of 'psychische Hemmung,' and showed how the threshold of
perception may be raised, for the various special senses, by the
interaction of rival sensations, justly contending that this shifting
of the threshold measures the degree in which the original sensation
is inhibited by its rival. But the field of inquiry was in that case
strictly sensational. We find also a discussion by Robert Saxinger,[6]
'Ueber den Einfluss der Gefuehle auf die Vorstellungsbewegung.' But the
treatment there, aside from the fact that it deals with the emotions,
is theoretical rather than experimental.

[2] Binet, A.: _Revue Philosophique_, 1890, XXIX., p. 138.

[3] Binet, A.: _Revue Philosophique_, 1890, XXX., p. 136.

[4] Binet, A., et Henri, V.: _Revue Philosophique_, 1894,
XXXVII., p. 608.

[5] Heymans, G.: _Zeitschrift f. Psych. u. Physiol. d.
Sinnesorgane_, 1899, Bd. XXI., S. 321; _Ibid._, 1901, Bd.
XXVI., S. 305.

[6] Saxinger, R.: _Zeitschrift f. Psych. u. Physiol. d.
Sinnesorgane_, 1901, Bd. XXVI., S. 18.

In short, it appears that though much has been said and done upon the
general subject of psychical inhibition, experimental inquiry into the
inhibitory effect of one idea upon another--abstraction made, as far
as possible, of all volitional influence--virtually introduces us to a
new phase of the subject.

The term 'idea,' it should be noted, is here used in its broadest
sense, and includes the memory image. In fact, the memory image and
its behavior in relation to another memory image formed the material
of the first part of the research, which alone is reported here.
Apparatus and method were both very simple.

The ideas to be compared were suggested by geometrical figures cut out
of pasteboard and hung, 25 cm. apart, upon a small black stand placed
on a table in front of the observer, who sat at a distance of four
feet from the stand. The diagrams and descriptions which follow will
show the character of these figures.

Before the figures were placed in position, the subject was asked to
close his eyes. The figures being placed, a few seconds' warning was
given, and at the word 'look' the subject opened his eyes and looked
at the objects, closing his eyes again at the word 'close.' The time
of exposure was five seconds. This time was divided as equally as
possible between the two figures, which were simultaneously exposed,
the observer glancing freely from one to the other as in the common
observation on which our ideas of objects are founded. At the end of
the exposure the subject sat with closed eyes and reported the several
appearances and disappearances of the ideas or mental images of the
objects just presented. The conditions required of him were that he
should await passively the entry of the rival claimants on his
attention, favoring neither and inhibiting neither; that is to say, he
was to remit all volitional activity, save so far as was necessary to
restrict his attention to the general field upon which the ideated
objects might appear, and to note what occurred on the field. The
period of introspection, which followed immediately the disappearance
of such retinal images as remained, after the closing of the eyes to
the external objects, lasted sixty seconds. The reports, like the
signals, were given in a just audible tone. They were in such terms as
'right--left,' 'small--large,' 'circle--star,' terms the simplest that
could be found, or such as seemed, in any given case, most naturally
or automatically associated with the object, and therefore least
likely to disturb the course of the observation. And each report was
noted down by the experimenter at the instant it was given, with the
time of each phase, in seconds, as indicated by a stop-watch under the
experimenter's eye.

It will be remarked that the attitude required of the observer was one
which is not commonly taken. And it may be objected that the results
of an attitude so unusual towards objects so ghostly and attenuated
must be too delicate, or too complex, or influenced by too many alien
suggestions, to be plumply set down in arabic numerals. The subjects,
in fact, did at first find the attitude not easy to assume. A visual
object may hold the attention by controlling the reflexes of the eye.
But an ideational object has ordinarily no sure command of the
conscious field save under the influence of a volitional idea or some
strongly toned affectional state. But with a little practice the
difficulty seemed to disappear. The subject became surer of his
material, and the mental object gradually acquired the same sort of
individuality as the visual object, though the impression it made
might be less intense.

After a few preliminary experiments, figures were devised for the
purpose of testing the effect of mere difference in the complexity of
outline. That is to say, the members of every pair of objects were of
the same uniform color-tone (Bradley's neutral gray No. 2), presented
the same extent of surface (approximately 42 sq. cm.), were exposed
simultaneously for the same length of time (5 seconds), and were in
contour usually of like general character save that the bounding line
in the one was more interrupted and complex than in the other.

In another series the variant was the extent of surface exposed, the
color-tone (neutral gray), outline, and other conditions being the
same for both members of each pair. The smaller figures were of the
same area as those of the preceding series; in the larger figures this
area was doubled. Only one member of each pair is represented in the
diagrams of this and the next series.

In a third series brightness was the variant, one member of each pair
being white and the other gray (Bradley's cool gray No. 2). All other
conditions were for both figures the same.

In still another series strips of granite-gray cardboard half a
centimeter wide were cut out and pasted on black cards, some in
straight and some in broken lines, but all of the same total length
(10 cm.). These were exposed under the same general conditions as
those which have already been described, and were intended to show the
relative effects of the two sorts of lines.

TABLE I.

1 2 3 4 5 Totals. Averages.
L R L R L R L R L R L R L R
I. 45 45 25 29 27 27 31 24 36 20 164 145 32.8 29
II. 20 25 28 28 28 19 31 31 28 14 135 117 27 23.5
III. 11 12 17 28 0 7 0 15 27 23 55 85 11 17
IV. 7 6 47 22 17 21 17 45 31 30 119 124 23.8 24.8
V. 27 33 46 36 40 31 44 31 26 35 183 165 36.6 33.2
VI. 11 14 32 29 34 21 14 35 0 46 91 145 18.2 29
VII. 36 33 30 30 50 50 22 22 52 52 190 187 38 37.4
VIII. 41 44 33 33 45 45 34 44 37 28 190 194 38 38.8
IX. 45 45 39 46 42 47 47 47 44 44 217 229 43.4 45.8
X. 40 39 24 25 19 21 21 23 18 25 122 133 24.4 26.6
XI. 51 53 52 50 42 42 42 42 42 42 229 229 45.8 45.8

334 349 373 356 344 331 303 359 341 359 1695 1754 30.8 31.9

The Arabic numerals at the head of the columns refer, in every
table, to the corresponding numerals designating the objects
in the diagram accompanying the table.

_L_: left-hand object.
_R_: right-hand object.

The Roman numerals (_I_ to _XI_) indicate the different
subjects. The same subjects appear in all the experiments, and
under the same designation. Two of the subjects, _IV_ and
_VIII_, are women.

The numbers under _L_ and _R_ denote the number of seconds
during which the left-hand image and the right-hand image,
respectively, were present in the period of introspection (60
seconds).

General average: _L_, 30.8 sec.; _R_, 31.9 sec.

[Illustration: FIG. 1.]

_Series No. 1._--For the purpose of obtaining something that might
serve as a standard of comparison, a series of observations was made
in which the members of every pair were exact duplicates of each
other, and were presented under exactly the same conditions, spatial
position of course excepted. The records of these observations are for
convenience placed first as Table I.

In treating the facts recorded in the accompanying tables as phenomena
of inhibition no assumption is implied, it may be well to repeat, that
the ideational images are forces struggling with each other for
mastery. Nor is it implied, on the other hand, that they are wholly
unconditioned facts, unrelated to any phenomena in which we are
accustomed to see the expression of energy. Inhibition is meaningless
save as an implication of power lodged somewhere. The implication is
that these changes are conditioned and systematic, and that among the
conditions of our ideas, if not among the ideas themselves, power is
exerted and an inferior yields to a superior force. Such force, in
accordance with our general presupposition, must be neural or
cerebral. Even mental inhibition, therefore, must ultimately refer to
the physical conditions of the psychical fact. But the reference, to
have any scientific value, must be made as definite as the case will
allow. We must at least show what are the conditions under which a
state of consciousness which might otherwise occur does not occur.
When such conditions are pointed out, and then only, we have a case of
what has been called psychical inhibition; and we are justified in
calling it inhibition because these are precisely the conditions under
which physiological inhibition may properly be inferred. And, we may
add, in order that the conditions may be intelligibly stated and
compared they must be referable to some objective, cognizable fact.
Here the accessible facts, the experiential data, to which the
psychical changes observed and the cerebral changes assumed may both
be referred, are visual objects, namely, the figures already
described.

What may occur when these objects are precisely alike, and are seen
under conditions in all respects alike except as to spatial position,
is indicated in Table I. The general average shows that the image
referred to the left-hand object was seen some 30 seconds per minute;
that referred to the right-hand image, some 31 seconds. Sometimes
neither image was present, sometimes both were reported present
together, and the time when both were reported present is included in
the account. In this series it appears, on the whole, that each image
has about the same chance in the ideational rivalry, with a slight
preponderance in favor of the right. Individual variations, which may
be seen at a glance by inspection of the averages, show an occasional
preponderance in favor of the left. But the tendency is, in most
cases, towards what we may call right-handed ideation.

_Series No. II._--In the second series (Table II.) we find that, other
things being equal, _an increase in the relative complexity of the
outline favors the return of the image to consciousness_. Including
the time when both images were reported present at once, the simpler
appears but 27 seconds per minute as against 34 seconds for the more
complex. No attempt was made to arrange the figures on any regularly
increasing scale of complexity so as to reach quantitative results.
The experiment was tentative merely.