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

or movement.

Certain rules were observed in the composition of the series. Since

the test was for permanence, to avoid confusion no number was used in

more than one couplet. No two numbers of a given series were chosen

from the same decade or contained identical final figures. No word was

used in more than one couplet. Their vowels, and initial and final

consonants were so varied within a single series as to eliminate

phonetic aids, viz., alliteration, rhyme, and assonance. The kind of

assonance avoided was identity of final sounded consonants in

successive words, e.g., lane, vine.

The series were composed in the following manner: After the

twenty-eight numbers for four series had been chosen, the words which

entered a given series were selected one from each of a number of

lists of words. These lists were words of like-sounded vowels. After

one word had been chosen from each list, another was taken from the

first list, etc. As a consequence of observing the rules by which

alliteration, rhyme, and assonance were eliminated, the words of a

series usually represented unlike categories of thought, but where two

words naturally tended to suggest each other one of them was rejected

and the next eligible word in the same column was chosen. The

following is a typical series from the A set.

A^{1}. Numbers and Nouns.

19 42 87 74 11 63 38

desk girl pond muff lane hoop vine

The apparatus used in the A set and also in all the later sets may

be described as follows: Across the length of a table ran a large,

black cardboard screen in the center of which was an oblong aperture

14 cm. high and 12 cm. wide. The center of the aperture was on a level

with the eyes of the subject, who sat at the table. The aperture was

opened and closed by a pneumatic shutter fastened to the back of the

screen. This shutter consisted of two doors of black cardboard sliding

to either side. By means of a large bulb the length of exposure could

be regulated by the operator, who stood behind the table.

The series—consisting of cards 4×2½ cm., each containing a printed

couplet—was carried on a car which moved on a track behind and

slightly below the aperture. The car was a horizontal board 150 cm.

long and 15 cm. wide, fixed on two four-wheeled trucks. It was divided

by vertical partitions of black cardboard into ten compartments, each

slightly wider than the aperture to correspond with the visual angle.

A curtain fastened to the back of the car afforded a black background

to the compartments. The couplets were supported by being inserted

into a groove running the length of the car, 3 cm. from the front. A

shutter 2 cm. high also running the length of the car in front of the

groove, fastened by hinges whose free arms were extensible, concealed

either the upper or the lower halves of the cards at the will of the

operator; i.e., either the foreign symbols or the words,

respectively. A screen 15 cm. high and the same length as the car,

sliding in vertical grooves just behind the cards and in front of the

vertical partitions, shut off the objects when desired, leaving only

the cards in view. Thus the apparatus could be used for all four types

of series.

The method of presentation and the time conditions of the A set were

as follows:—A metronome beating seconds was used. It was kept in a

sound-proof box and its loudness was therefore under control. It was

just clearly audible to both operator and subject. In learning, each

couplet was exposed 3 secs., during about 2 secs. of which the shutter

was fully open and motionless. During this time the subject read the

couplet inaudibly as often as he wished, but usually in time with the

metronome. His object was to associate the terms of the couplet. There

was an interval of 2 secs. after the exposure of each couplet, and

this was required to be filled with repetition of only the

immediately preceding couplet. After the series had been presented

once there was an interval of 2 secs. additional, then a second

presentation of it commenced and after that a third. At the completion

of the third presentation there was an interval of 6 secs. additional

instead of the 2, at the expiration of which the test commenced.

A^{13-16} had five presentations instead of three. The test

consisted in showing the subject either the numbers or the words in

altered order and requiring him to write as many of the absent terms

as he could. In the object and movement series the objects were also

shown and the movements repeated by the subject if words were the

given terms. The time conditions in the test were,

Exposure of a term 3 secs.

Post-term interval in A^{1-12} 4 secs.

Post-term interval in A^{13-16} 6 secs.

This allowed the subject 7 secs. for recalling and writing each term

in A^{1-12} and 9 sec. in A^{13-16}. If a word was recalled after that

time it was inserted, but no further insertions were made after the

test of a series had been completed. An interval of 3 min. elapsed

between the end of the test of one series and the beginning of the

next series, during which the subject recorded the English word of any

couplet in which an indirect association had occurred, and also his

success in obtaining visual images if the series was a noun or a verb

series.

As already indicated, four series—a noun, an object, a verb, and a

movement series—given within a half hour, constituted a day’s work

throughout the year. Thus variations due to changes in the

physiological condition of the subject had to affect all four types of

series.

Two days later these series were tested for permanence, and in the

same way as the tests for immediate recall, with this exception:

Post-term interval in A^{13-16} 8 secs.

Thus 11 secs. were allowed for the deferred recall of each term in

A^{13-16}.

In the movement series of this set, to avoid hesitation and confusion,

the operator demonstrated to the subject immediately before the series

began, once for each word, how the movements were to be made.

The A set was given to three subjects. The results of each subject

are arranged separately in the following table. In the tests the words

were required in A^{1-4}, in A^{5-16} the numbers. The figures show

the number of terms correctly recalled out of seven couplets in

A^{1-12} and out of five couplets in A^{13-16}, exclusive of

indirect association couplets. The figures in brackets indicate the

number of correctly recalled couplets per series in which indirect

associations occurred. The total number correctly recalled in any

series is their sum. The figures in the per cent. row give the

percentage of correctly recalled couplets left after discarding both

from the number recalled and from the total number of couplets given

those in which indirect associations occurred. This simply diminished

the subject’s number of chances. A discussion of the propriety of this

elimination will be found later. In A^{1-12} the absent terms had to

be recalled exactly in order, to be correct, but in A^{13-16}, on

account of the greater difficulty of the three-place numbers, any were

considered correct when two of the three figures were recalled, or

when all three figures were correct but two were reversed in position,

e.g., 532 instead of 523. N means noun series, O object, V

verb, and M movement series. Series A^{1}, A^{5}, A^{9},

A^{13} are to be found in the first and third columns, A^{2},

A^{6}, A^{10}, A^{14} in the second and fourth, A^{3},

A^{7}, A^{11}, A^{15}, in the fifth and seventh, and A^{4},

A^{8}, A^{12}, A^{16} in the sixth and eighth columns.

TABLE I.

SHOWING IMMEDIATE RECALL AND RECALL AFTER TWO DAYS.

M.

Series. Im. Rec. Two Days. Im. Rec. Two Days.

N. O. N. O. V. M. V. M.

A^{1-4} 6 7 3 1 6 7 2 1

A^{5-8} 5(1) 6 3(1) 6 6(1) 7 5(1) 6

A^{9-12} 7 7 4 6 7 6(1) 7 6(1)

A^{13-16} 4 5 2 2 5 3 2 2

Total. 22(1) 25 12(1) 15 24(1) 23(1) 16(1) 15(1)

Per cent. 88 96 48 58 96 92 64 66

S.

Series. Im. Rec. Two Days. Im. Rec. Two Days.

N. O. N. O. V. M. V. M.

A^{1-4} 6(1) 6 0 0 7 7 0 0

A^{5-8} 6 7 1 3 6 7 0 3

A^{9-12} 7 6 2 2 5 7 0 0

A^{13-16} 5 5 0 0 5 5 3 0

Total. 24(1) 24 3 5 23 26 3 3

Per cent. 96 92 12 19 88 100 12 12

Hu.

Series. Im. Rec. Two Days. Im. Rec. Two Days.

N. O. N. O. V. M. V. M.

A^{1-4} 6 7 0 1 5 6(1) 0 2

A^{5-8} 5(2) 7 1(2) 1 7 7 1 0

A^{9-12} 6(1) 7 2 2 6 7 0 5

A^{13-16} 4(1) 4(1) 0 2 5 5 0 1

Total. 21(4) 25(1) 3(2) 6 23 25(1) 1 8

Per cent. 95 100 14 24 88 100 4 32

These results will be included in the discussion of the results of the

B set.

THE B SET.

A new material was needed for foreign symbols. After considerable

experimentation nonsense words were found to be the best adapted for

our purpose. The reasons for this are their regularly varying length

and their comparative freedom from indirect associations. An objection

to using nonsense syllables in any work dealing with the permanence of

memory is their sameness. On this account they are not remembered

long. To secure a longer retention of the material, nonsense words

were devised in substantially the same manner as that in which Müller

and Schumann made nonsense syllables, except that these varied

regularly in length from four to six letters. Thus the number of

letters, not the number of syllables was the criterion of variation,

though of course irregular variation in the number of syllables was a

necessary consequence.

When the nonsense words were used it was found that far fewer indirect

associations occurred than with nonsense syllables. By indirect

association I mean the association of a foreign symbol and its word by

means of a third term suggested to the subject by either of the others

and connected at least in his experience with both. Usually this

third term is a word phonetically similar to the foreign symbol and

ideationally suggestive of the word to be associated. It is a very

common form of mnemonic in language material. The following are

examples:

cax, stone (Caxton);

teg, bib (get bib);

laj, girl (large girl);

xug, pond (noise heard from a pond);

gan, mud (gander mud).

For both of these reasons nonsense words were the material used as

foreign symbols in the B set.

The nonsense words were composed in the following manner. From a box

containing four of each of the vowels and two of each of the

consonants the letters were chosen by chance for a four-letter, a

five-letter, and a six-letter word in turn. The letters were then

returned to the box, mixed, and three more words were composed. At the

completion of a set of twelve any which were not readily pronounceable

or were words or noticeably suggested words were rejected and others

composed in their places.

The series of the B set were four couplets long. Each series

contained one