Ploog, B. O., & Zeigler, H. P. (1997).
Key-peck probability and topography in a concurrent variable-interval variable-interval schedule with food and water reinforcers.
Journal of the Experimental Analysis of Behavior,
67, 109-129.
The relation between variables that modulate the probability and
the topography of key pecks was examined using a concurrent
variable-interval variable-interval schedule with food and water
reinforcers. Measures of response probability (response rates,
time allocation) and topography (peck duration, gape amplitude)
were obtained in 5 water- and food-deprived pigeons. Key color
signaled reinforcer type. During baseline, response rates and
time allocations were greater to the food key than to the water
key, and food-key pecks had larger gapes and shorter durations.
Relative probability measures (for the food key) were increased
by prewatering and decreased by prefeeding. Deprivation effects
upon topography measures were apparent only when food- and
water-key pecks were analyzed separately. Food-key gape
amplitudes increased with prewatering and decreased with
prefeeding. The clearest effect occurred with prewatering. There
were no consistent effects upon water-key gapes. The key
color—reinforcer relation was reversed for 3 pigeons to
determine how response topography was modulated during the
transition from food- to water-key pecks. Reacquisition was
faster for the probability than for the topography measures.
Analysis of gape-amplitude distributions during reversal
indicated that response-form modulation proceeded through the
generation of intermediate gape sizes.
Key words: concurrent VI VI, response rate, time allocation,
topography, reinforcer quality, deprivation, pigeon