Baum, W. M. & Davison, M. (2004).
Choice in a variable environment: Visit patterns in the dynamics of choice.
Journal of Experimental Analysis of Behavior,
81, 85-127.
Molar and molecular views of behavior imply different approaches to data
analysis. The molecular view privileges moment-to-moment analyses, whereas the
molar view supports analysis of more and less extended activities. In
concurrent performance, the molar view supports study of both extended patterns
of choice and more local patterns of visiting the choice alternatives. Analysis
of the present data illustrated the usefulness of investigating order at various
levels of extendedness. Seven different reinforcer ratios were presented within
each session, without cues to identify them, and pigeons pecked at two response
keys that delivered food on variable-interval schedules. Choice changed rapidly
within components as reinforcers were delivered and, following each reinforcer,
shifted toward the alternative that produced it. If several reinforcers were
delivered consecutively by one alternative, choice favored that alternative, but
shifted more slowly with each new reinforcer. A discontinuation of such a
series of reinforcers by the delivery of a reinforcer by the other alternative
resulted in a large shift of choice toward that alternative. These effects were
illuminated by analysis of visits to the two alternatives. Changes in visit
length occurred primarily in the first postreinforcer visit to the repeatedly
reinforced alternative. All other visits tended to be brief and equal.
Performance showed multiple signs of moving in the direction of a fix-and-sample
pattern that characterized steady-state performance in earlier experiments with
many sessions of maintaining each schedule pair. The analyses of extended and
local patterns illustrate the flexibility of a molar view of behavior.
Key words: choice, dynamics, molar view, visit patterns, fix and
sample, key peck, pigeons