Transfer of matching-to-figure samples in the pigeon

Concept Learning and Learning Strategies

Concept learning and learning strategies of pigeons were manipulated in a matching-to-sample task. Groups of 4 pigeons responded either 0, 1, 10, or 20 times to a sample stimulus, and then chose between a matching comparison stimulus and a nonmatching comparison stimulus. Tests with unfamiliar arrangements of the three training stimuli showed that learning was not by if-then rules. Tests with novel stimuli showed that as the number of sample responses increased, learning about the configural pattern of each display gave way to more learning about the sample-comparison relationship and more concept learning. Pigeons making the most sample responses showed complete concept learning.

Matching and oddity relational learning by pigeons (Columba livia): transfer from color to shape

Relational learning, as opposed to perceptual learning, is based on the abstract properties of the stimuli. Although at present there is no doubt that pigeons are capable of relational behavior, this study aims to further disclose the conditions under which it occurs. Pigeons were trained in an outdoor cage on a matching-to-sample or an oddity-from-sample task, with colored cardboard stimuli presented horizontally. The apparatus involved three sliding lids on which the stimuli were drawn and which, when displaced, revealed the reinforcement. The lids were either adjacent to each other or somewhat separated. Training sessions involved two colors, and test sessions six different colors (same dimension test), or six different shapes (different dimension test). One group of birds trained under the 'adjacent' condition failed when tested with new stimuli, but succeeded in both dimension tests after training under the 'separate' condition. Two other groups of birds succeeded in all tests after training under the latter condition. These results show that depending on procedural details, pigeons are or are not able to transfer from one visual dimension to another, thus extending previous related findings.

Transfer of oddity-from-compound samples in the pigeon: Some assembly required

Experiment 1 trained three pigeons on a six-key oddity-from-sample procedure. At trial onset, one of two compound color-form sample stimuli was presented (a white 'X' on a red background or a white circle on a green background). Every second peck on the sample key lighted another comparison stimulus up to a maximum of four stimuli (red, green, circle and X). A peck on the two keys that presented non-matching color and form stimuli, relative to the compound sample, lighted a reinforcement key. A peck to this key produced grain. Errors darkened the comparison keys and repeated the trial. The birds learned to perform without error during 70-80% of the session trials, and showed transfer of oddity performance to eight novel compound samples. Experiment 2 presented the pigeons with novel combinations of familiar color and form stimuli. Each bird performed well above chance indicating that their behavior was under the control of an oddity concept.

Levels of stimulus control: a functional approach

This paper surveys some illustrative experiments on categorization of visual stimuli by animals other than human. The results suggest a classification of categorical powers in five steps from simple discrimination to rote and open-ended categorization, to concepts and the use of abstract relations. Nonhuman animals evidently readily categorize up to the fourth level as here defined, which is the level of concepts. With difficulty, they can sometimes be induced to rise even to the level of abstract relations. It is at the level of abstract relations that a large gap opens up between human categorizations and categorization by other animals.

Teaching pigeons an abstract relational rule: insideness

In 49 sessions, pigeons failed to learn to sort a collection of 80 stimuli composed of a closed curve and a dot, divided into two categories, according to whether the dot was or was not inside the curve. Next, the pigeons were successfully trained, first with the insides of the curves shown in bright red, then with a darker red, and finally with a black matching the background outside the curve. After this stepwise procedure, the pigeons displayed a limited ability to sort novel curves and dot locations according to whether the dot was or was not inside the curve.

Auditory word discriminations in the pigeon

Four pigeons were trained on a multiple variable-interval 30-s extinction schedule with various pairs of spoken English words presented as the discriminative stimuli. The birds typically produced discrimination indices of 70% to 90% accuracy. Discrimination accuracy was improved by shortening the interval between auditory stimulus presentations, and by increasing the number of syllables in the words.