The Evolution
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The point is that a memorization task involving phrases such as
apple container and donkey kick might allow the subject to use any of
several images to store the same information, and these images might
be arrived at by Type I, Type II, or Type IV processing, and might be
retrieved by Type I, Type II, or Type IV retrieval. Thus by its very
nature the memorization task must gratuitously introduce added levels
of complexity that prevent the theorist from developing a clear pic-
ture of what is really going on in memory.
In contrast a carefully constructed intersection task involves
information retrieval only, with the memory under examination forced
to act along predetermined channels. In this way the job of the theorist
normally an impossible one, becomes just manageable.
Link Identification
It follows from all that has been said so far that one of the
major goals of psychology should be to identify by means of intersection
experiments (e.g. Freedman & Loftus, 1971) what in memory is linked to
what, and then to identify which of these links are whole-to-whole
links and which part-whole links. Thus if A and B yield by inter-
section Z, A and B must have some kind of link with Z. Identifying
which type they are requires the use of the following three principles
(note that these principles are merely convenient reformulations of
principles deduced earlier).