Ludvig, E. A. & Staddon, J. E. R. (2005).
The effects of interval duration on temporal tracking and alternation learning.
Journal of the Experimental Analysis of Behavior, 83, 243-262.
On cyclic-interval reinforcement schedules, animals typically show a
postreinforcement pause that is a function of the immediately preceding time
interval (temporal tracking). Animals, however, do not track single-alternation
schedules—when two different intervals are presented in strict alternation on
successive trials. In this experiment, pigeons were first trained with a cyclic
schedule consisting of alternating blocks of 12 short intervals (5 s or 30 s)
and 12 long intervals (180 s), followed by three different single-alternation
interval schedules: (a) 30 s and 180 s, (b) 5 s and 180 s, and (c) 5 s and 30 s.
Pigeons tracked both schedules with alternating blocks of 12 intervals. With the
single-alternation schedules, when the short interval duration was 5 s,
regardless of the duration of the longer interval, pigeons learned the
alternation pattern, and their pause anticipated the upcoming interval. When the
shorter interval was 30 s, even when the ratio of short to long intervals was
kept at 6:1, pigeons did not initially show anticipatory pausing—a violation of
the principle of timescale invariance.
Key words: fixed interval, schedule history, temporal control, lever press,
rats