The Evolution

The Evolution

26

Invalidation and Residual Activation

Actually there is another reason to expect that memory stores its
information in part-whole and whole-to-whole links. Consider again
the concepts "hospital” and "blade." It is a fact that the
whole-to-whole links emanating from "hospital" provide information that
retains its usefulness for some time—that is, once one has perceived
"hospital," those concepts associated with it ("doctor," "nurse," "scal-
pel," "beds,” etc.) have a higher probability for some time afterward,
probably for many minutes. But the same cannot be said for the informa-
tion offered by the part-whole links of "blade." Thus if "blade” is per-
ceived and successfully disambiguated as, say, "scalpel," that success-
ful disambiguation would invalidate "kitchen Knife," "pocketknife,"
"butter knife," etc. as concepts to be regarded as more likely than
usual. In contrast, none of the whole-to-whole links emanating from
"hospital" would in any way be invalidated by the occurrence of, say,
"doctor"; in fact, the concepts "nurse," "scalpel," and "beds" would,
if anything, be more likely by virtue of the occurrence of "doctor"
supporting memory's original expectations.

Put another way, if one saw a hospital and expected to see doctors,
nurses, scalpels, and beds, etc., one would regard this class of expecta-
tions as even more valid if one of them were to occur.

In contrast, if one saw a blade and expected it to be either a
scalpel, kitchen knife, or pocketknife, etc., one would regard this
class of expectations as invalidated if one of them were confirmed as the
blade seen. If a blade were ultimately correctly disambiguated as a

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