Comparison Of Lines
PROCEDURE. Present the appropriate accompanying card with the lines in
horizontal position. Point to the lines and say: "_See these lines. Look
closely and tell me which one is longer. Put your finger on the longest
one._" We use the superlative as well as the comparative form of _long_
because it is often more familiar to young subjects. If the child does
not respond, say: "_Show me which line is the biggest._" Then withdraw
the card, turn it about a few times, and present it again with the
position of the two lines reversed, saying: "_Now show me the longest._"
Turn the card again and make a third presentation.
SCORING. All three comparisons must be made correctly; or if only two
responses out of three are correct, all three pairs are again shown,
just as before, and if there is no error this time, the test is passed.
The standard, therefore, is _three correct responses out of three, or
five out of six_.
Sometimes the child points, but at no particular part of the card. In
such cases it may be difficult to decide whether he has failed to
comprehend and to make the discrimination or has only been careless in
pointing. It is then necessary to repeat the experiment until the
evidence is clear.
REMARKS. As noted by Binet, success in this test depends on the
comprehension of the verbal directions rather than on actual
discrimination of length. The child who would unerringly choose the
larger of two pieces of candy might fail on the comparison of lines.
However, since the child must correctly compare the lines three times in
succession, or at least in five out of six trials, _willingness to
attend_ also plays a part. The attention of the low-grade imbecile, or
even of the normal child of 3 years, is not very obedient to the
suggestions of the experimenter. It may be gained momentarily, but it is
not easily held to the same task for more than a few seconds. Hence some
children who perfectly comprehend this task fail to make a succession of
correct comparisons because they are unable or unwilling to bring to
bear even the small amount of attention which is necessary. This does
not in the least condone the failure, for it is exactly in such
voluntary control of mental processes that we find one of the most
characteristic differences between bright and dull, or mature and
There has been little disagreement as to the proper location of this