The Evolution
20
Note that if memory treated the "eggs" profile as more important
than the "Florida" profile, which is less recent, the above diffi-
culties would increase rather than decrease.
An analysis of a Type II Intersection
Now it is possible to demonstrate that plugging the same values
used above into the corresponding Type II intersection completely
alters the expectations of an optimized memory, and turns the task of
intersection into one easy for memory to carry out.
The corresponding Type II intersection involving the concepts
"hospital" and "blade" requires that the concept "hospital" occur with
a probability of .0001 (i.e. once in every 10,000 percepts as was the
case with "Florida"), and that "blade" in one form or another (e.g.
"pocketknife," "breadknife," or "scalpel," etc.) likewise occur with
a probability of .0001 (the same as "eggs"). It is also necessary to
assume that over the course of a lifetime the following profile is
established for "hospital":
"hospital" ---------------> "breadknife" (zero probability)
---------------> "scalpel" (.01)
And that the following profile emanates from the concept "blade":
"blade" ------------------> "breadknife" (.5)
------------------> "scalpel" (.04)
Note that these two profiles incorporate probabilities that are
identical with those used with "Florida" and "eggs." The important
difference introduced there is that the part-whole links of "blade