WITHIN-SESSION DISCRIMINATION BETWEEN TIMES OF REINFORCERS IN THE MINUTES RANGE BY PIGEONS

This experiment tested whether pigeons could discriminate between a la rge reinforcer delivered at 6 min (early) vs. 16 min (late) within a 2 0 min session. A within subject design was used in which an early rein forcer was delivered in one context, and a late reinforcer in another. Rate of responding on the first link of a chain schedule was higher i n the early reinforcer condition. Furthermore, in probe sessions durin g which no large reinforcer was delivered, the discrimination was main tained. Implications for foraging are discussed.