Harold Pashler has an interesting article in the Jan-Feb American
Scientist: "Doing Two Things at the Same Time." He discusses studies of
where the brain single-threads. There are two places in particular:
attention and response selection, and these are independent, since you can
be attending to a stimulus and selecting a response to another stimulus
Desimone's evidence on attention is interesting in this context. He showed
that there are two forms, one involving scanning for a known pattern and
the other detecting novelty. Novelty detection may not be single-threaded,
since it seems to involve arrays of neurons that remember recent patterns.
Scanning for a known pattern seems to involve the superposition of two
arrays, one with the scene and the other with the points of interest. This
does sound like Freeman's process in the olfactory system, which -->has<--
to be single-threaded.
The response-selection process is associated with memory retrieval
according to Pashler. This also makes sense if memory retrieval is similar
to Freeman's process--only one memory can be retrieved at a time.
A third type of process that may have the same characteristics is
planning. Is there evidence for single-threading here?
Internet: erwin at trwacs.fp.trw.com
Looking for interesting work...