Repeating Five Digits
PROCEDURE. Use: 3-1-7-5-9; 4-2-3-8-5; 9-8-1-7-6. Tell the child to
listen and to say after you just what you say. Then read the first
series of digits at a slightly faster rate than one per second, in a
distinct voice, and with perfectly uniform emphasis. _Avoid rhythm._
In previous tests with digits, it was permissible to re-read the first
series if the child refused to respond. In this year, and in the digits
tests of later years, this is not permissible. Warning is not given as
to the number of digits to be repeated. Before reading each series, get
the child's attention. Do not stare at the child during the response, as
this is disconcerting. Look aside or at the record sheet.
SCORING. Passed if the child repeats correctly, after a single reading,
_one series out of the three_ series given. The order must be correct.
REMARKS. Psychologically the repetition of digits differs from the
repetition of sentences mainly in the fact that digits have less meaning
(fewer associations) than the words of a sentence. It is because they
are not as well knit together in meaning that three digits tax the
memory as much as six syllables making up a sentence.
Testing auditory memory for digits is one of the oldest of intelligence
tests. It is easy to give and lends itself well to exact quantitative
standardization. Its value has been questioned, however, on two grounds:
(1) That it is not a test of pure memory, but depends largely on
attention; and (2) that the results are too much influenced by the
child's type of imagery. As to the first objection, it is true that more
than one mental function is brought into play by the test. The same may
be said of every other test in the Binet scale and for that matter of
any test that could be devised. It is impossible to isolate any function
for separate testing. In fact, the functions called memory, attention,
perception, judgment, etc., never operate in isolation. There are no
separate and special "faculties" corresponding to such terms, which are
merely convenient names for characterizing mental processes of various
types. In any test it is "general ability" which is operative, perhaps
now _chiefly_ in remembering, at another time _chiefly_ in sensory
discrimination, again in reasoning, etc.
The second objection, that the test is largely invalidated by the
existence of imagery types, is not borne out by the facts. Experiments
have shown that pure imagery types are exceedingly rare, and that
children, especially, are characterized by "mixed" imagery. There are
probably few subjects so lacking in auditory imagery as to be placed at
a serious disadvantage in this test.
Lengthening a series by the addition of a single digit adds greatly to
the difficulty. While four digits can usually be repeated by children of
4 years, five digits belong in year VII and six in year X.
It is always interesting to note the type of errors made. The most
common error is to omit one or more of the digits, usually in the first
part of the series. If the child's ability is decidedly below the test
he may give only the last two or three out of the five or six heard.
Substitutions are also quite frequent, and if so many substitutions are
made as to give a series quite unlike that which the child has heard, it
is an unfavorable sign, indicating weakness of the critical sense which
is so often found with low-level intelligence. In case of extreme
weakness of the power of auto-criticism, the child in response to the
series 9-8-1-7-6-, may say 1-2-3-4-5-6, or perhaps merely a couple of
digits like 8-6, and still express complete satisfaction with his absurd
response. After each series, therefore, the examiner should say, "_Was
it right?_" Very young subjects, however, have a tendency to answer
"yes" to any question of this type, and it is therefore best not to call
for criticism of a performance below the age of 6 or 7 years.
Digit series of a given length are not always of equal difficulty, and
for this reason it is never wise to use series improvised at the moment
of the experiment. We must avoid especially series of regularly
ascending or descending value, the repetition at regular intervals of a
particular digit, and all other peculiarities of arrangement which would
favor the grouping of the digits for easier retention.
It remains to mention two or three further cautions in regard to
procedure. It is best to begin with a series about one digit below the
child's expected ability. If the child has a probable intelligence of
about 6 or 7 years, we should begin with four digits; in case of
probable 10-year intelligence we begin with five digits, etc. On the
other hand, we should avoid beginning too far down, because then the
result is too much complicated by the effects of practice and fatigue.
It is not necessary, and often it is not expedient, to give the digits
tests of all the different years in succession; that is, without other
tests intervening. While this may be permissible with older children, in
young children the power of sustained attention is so weak that no
single kind of test should occupy more than two or three minutes.
Children below 6 or 7 years should ordinarily be given the tests in the
order in which they are listed in the record booklet.
In his 1911 revision of the scale Binet unfortunately shifted this test
from year VII to year VIII. Goddard follows his example, but Kuhlmann
retains it in year VII. The data from more than a dozen leading
investigations in America, England, and Germany agree in showing that
the test should remain in year VII.