Autoshaped Responding: A Baseline for Studying Stimulus Preference

Abstract

In an autoshaping procedure with pigeons, trials consisted of the illumination of two keys, each with a different color, and then a response-independent feeder operation. Over successive conditions, all key-color pairs were arranged from the set of amber, red, green, and blue lamps. During sessions with a given pair, the left-right configuration of the colors varied irregularly, and the two colors alternated in illuminating the feeder. With one red and one green key, for example, red appeared sometimes on the left and sometimes on the right, and the feeder was alternately lit red or green on successive trials. Both total pecks and proportion of trials with at least one peck on a key of a given color were generally greater for red and amber than for green and blue, and relations among preferences were generally transitive across different color pairs. Repeating the procedure with decreased red and amber intensities and increased green and blue intensities reduced red and amber pecking relative to green and blue pecking, implying that differences in responding were determined more strongly by intensive than by chromatic properties of the stimuli.

Color Preference in Pigeons: Stimulus Intensity and Reinforcement Contingency Effects in the Avoidance of Blue Stimuli

“…The results of Experiments 1, 2, and 2a suggested that color preference as described by Catania et al (1983) may have been controlled by the intensity of the stimuli rather than by the chromatic properties. We obtained samples of three of the original color stimuli used by Catania et al and measured their respective intensities, which were 44,000 lx for red, 6,875 lx for green, and 5,500 lx for blue.…”

“…In Experiments 1 and 2, each peck was followed by reinforcement, whereas in Catania et al (1983) grain was delivered in a strictly response-independent arrangement that was, in effect, an autoshaping procedure similar to that of Brown and Jenkins (1968). The importance of this difference between Experiments 1 and 2 and those of Catania et al was assessed in Experiment 3, in which we used a response-independent reinforcement procedure.…”

“…Six naive pigeons with the same characteristics as in Experiments 1, 2, and 2a were used. The apparatus and procedure were identical to Experiment 2 (in which all stimuli were presented at 350 lx), except that reinforcement was programmed in a response-independent procedure identical to that used by Catania et al (1983), in which the sequence of trial events was an ITI of 24 s, 3 s of lit keys, and finally a 3-s presentation of the feeder.…”

“…An automated experimental chamber (Grason-Stadler model no. E6446 CA-1, 32 cm wide, 34 cm high, and 35 cm deep) was modified so that two 2.5-cm response keys were separated by 6.5 cm and were 23 cm above the grid, as in the study by Catania et al (1983). A standard Gerbrands feeder was centered below the keys.…”

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In a procedure intended to determine color preference in pigeons (which partially replicated Catania, Owens, & von Lossberg, 1983), two keys were illuminated by different colors drawn from a set of amber, red, green, or blue stimuli; this was followed by the presentation of grain when either of the two colors was pecked. The grain was illuminated alternately across trials with the colors presented on the keys.

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