The Evolution

The Evolution
35

The Effect of Order on Type II Intersection

A production experiment was conducted by Freedman and Loftus
(1971) in which subjects were presented noun categories (e.g. animal,
fruit, president, etc.) followed .5 to 5 sec later (or preceded .5 to
15 sec earlier) by restricting letter, and were asked to carry out an
intersection. For example, animal followed by Z (or Z followed by animal) was
supposed to provoke a response such as Zebra. It was clearly demonstrated
that a quicker response was possible when the noun category was presented
first and the letter second (reaction times were measured from the
presentation of the second item).

Freedman and Loftus interpret this result by arguing that if the
noun animal occurs first, a certain portion of the intersection process
may be carried out even before Z occurs, whereas if the letter occurs
first, there is no corresponding activity that may be profitably under-
taken by memory, and therefore memory must bide its time while waiting
for the noun animal to occur. This portion of wasted time is, according
to Freedman and Loftus, the reason for the difference in reaction times.

The theory of part-whole and whole-to-whole linking can account for
the above asymmetrical reaction times in two ways. First, it is possible
to argue that whole-to-whole links (such as the one that runs between the
concept "animal" and the word Zebra) take longer ot activate than part-whole
links, perhaps because unlike part-whole links they may undergo residual
activation. It follows that in intersecting a noun category with a letter,
memory saves more time if the noun is presented ahead of time than if
the letter is, because activating the whole-to-whole links of the noun
is a more time-consuming procedure than activating the part-whole links of

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