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R J Herrnstein

Publications and source records attributed to R J Herrnstein.

At least 19 recordsLinked to original sources
PubMed1990

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.

Animals↗
PubMed1989

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.

Animals↗
PubMed1987

Discriminating figure from ground: the role of edge detection and region growing.

Three general classes of algorithms have been proposed for figure/ground segregation. One class attempts to delineate figures by searching for edges, whereas another class attempts to grow homogeneous regions; the third class consists of hybrid algorithms, which combine both procedures in various ways. The experiment reported here demonstrated that humans use a hybrid algorithm that makes use of both kinds of processes simultaneously and interactively. This conclusion follows from the patterns of response times observed when humans tried to recognize degraded polygons. By blurring the edges, the edge-detection process was selectively impaired, and by imposing noise over the figure and background, the region-growing process was selectively impaired. By varying the amounts of both sorts of degradation independently, the interaction between the two processes was observed.

Adult↗
PubMed1987

Choosing among natural stimuli.

Pigeons worked on concurrent variable-interval, variable-interval schedules with the alternatives signaled by slides either containing trees or not. The schedules were designed to hold both overall and relative rates of reinforcement within narrowly constrained limits, and slides were quasi-randomly ordered each day. Responding to the two alternatives was well described by the generalized matching equation with substantial undermatching. Using an adaptation of the matching law, we estimated that the subjects were correctly classifying 82% to 95% of exemplars. The matching performance transferred to new exemplars of trees and nontrees with only slight generalization decrement. The pigeons appeared to be discriminating among exemplars even when the alternatives provided equal rates of reinforcement and the average relative performances were close to 50%.

Journal Article↗
PubMed1986

More on concurrent interval-ratio schedules: a replication and review.

It has been suggested that the failure to maximize reinforcement on concurrent variable-interval, variable-ratio schedules may be misleading. Inasmuch as response costs are not directly measured, it is possible that subjects are optimally balancing the benefits of reinforcement against the costs of responding. To evaluate this hypothesis, pigeons were tested in a procedure in which interval and ratio schedules had equal response costs. On a concurrent variable time (VT), variable ratio-time (VRT) schedule, the VT schedule runs throughout the session and the VRT schedule is controlled by responses to a changeover key that switches from one schedule to the other. Reinforcement is presented independent of response. This schedule retains the essential features of concurrent VI VR, but eliminates differential response costs for the two alternatives. It therefore also eliminates at least one significant ambiguity about the reinforcement maximizing performance. Pigeons did not maximize rate of reinforcement on this procedure. Instead, their times spent on the alternative schedules matched the relative rates of reinforcement, even when schedule parameters were such that matching earned the lowest possible overall rate of reinforcement. It was further shown that the observed matching was not a procedural artifact arising from the constraints built into the schedule.

Animal Feed↗
PubMed1982

Stimuli and the texture of experience.

Evidence from human language learning and stimulus control of learned and unlearned behavior suggests that generalization and categorization are based on principles of similarity that have evolved to favor the perception of recurrent events and extended objects. The perceptual similarities are typically more complex than, and only occasionally approximated by, physical similarity. In some, but not all, cases, perceptual similarity is tantamount to innate knowledge.

Animals↗
PubMed1979

Acquisition, generalization, and discrimination reversal of a natural concept.

Pigeons rapidly acquired a discrimination between 40 pictures containing trees and 40 not containing trees. Differential reinforcement did not affect the discriminability of individual instances of trees. Generalization to new instances of tree pictures was better than to new instances of non-tree pictures. The level of discrimination did not depend on whether trees constituted the reinforced or the unreinforced category.

Animals↗
PubMed1979

Is matching compatible with reinforcement maximization on concurrent variable interval variable ratio?

Four pigeons on concurrent variable interval, variable ratio approximated the matching relationship with biases toward the variable interval when time spent responding was the measure of behavior and toward the variable ratio when frequency of pecking was the measure of behavior. The local rates of responding were consistently higher on the variable ratio, even when there was overall preference for the variable interval. Matching on concurrent variable interval, variable ratio was shown to be incompatible with maximization of total reinforcement, given the observed local rates of responding and rates of alternation between the schedules. Furthermore, it was shown that the subjects were losing reinforcements at a rate of about 60 per hour by matching rather than maximizing.

Journal Article↗
PubMed1976

Matching in a network.

Pigeons were given practice choosing between pairs of alternatives yielding different frequencies of reinforcement. Four individual alternatives were set into four pairwise choices. Averaged over subjects, the distribution of responses in each choice approximated matching. The four individual alternatives were then presented, two by two, in two pairwise choices for which there had been no initial practice. No further reinforcement was given during the tests with the new pairs. Transfer to the two test pairs deviated systematically from matching in most cases by exaggerating the preference for the alternative that had had the higher frequency of reinforcement.

Journal Article↗
PubMed1975

Maximizing and matching on concurrent ratio schedules.

Pigeons on concurrent variable-ratio variable-ratio schedules usually, though not always, maximize reinforcements per response. When the ratios are equal, maximization implies no particular distribution of responses to the two alternatives. When the ratios are unequal, maximization calls for exclusive preference for the smaller ratio. Responding conformed to these requirements for maximizing, which are further shown to be consistent with the conception of reinforcement implicit in the matching law governing relative responding in concurrent interval schedules.

Journal Article↗
PubMed1974

Formal properties of the matching law.

The matching law implies that any form of behavior approaches an asymptotic frequency as its reinforcement approaches 100 per cent of the total reinforcement being obtained at a given time. This asymptote is formally independent of the kind or quantity of drive or reinforcement associated with the response in question or with any competing response.

Journal Article↗
PubMed1974

Hunger and contrast in a multiple schedule.

Pigeons working for food on a multiple variable-interval 1-min-variable-interval 4-min schedule were subjected to variations in body weight, presumably causing changes in hunger. The proportion of responses in each component approached and eventually reached the proportion of reinforcements as body weight increased. This effect follows from the matching-law interpretation of contrast in multiple schedules.

Animals↗
PubMed1972

Food-avoidance in hungry pigeons, and other perplexities.

Twenty-three pigeons were subjected to a series of procedures in which the key-peck's effects ranged from immediate, differential food reinforcement, through delayed reinforcement, the production of stimulus changes with and without probable secondary reinforcement, the prevention of food presentation ("food-avoidance"), to extinction. Neither primary nor secondary food reinforcement appeared to be essential for the maintenance or acquisition of key pecking. The food-avoidance contingency failed to suppress responding in any subject. Only complete extinction, when pecking produced neither food nor stimulus changes, eliminated all pecking for most subjects. A combination of stimulus-change reinforcement and food reinforcement appeared to account for the results, but only if it could be assumed that the presence of food in a procedure enhanced the reinforcing power of stimulus change, whether or not the food was also dependent upon responding. Such an interaction between reinforcers may be involved in the phenomenon of autoshaping.

Animals↗
PubMed1970

Timing in free-operant and discrete-trial avoidance.

A procedure ("discrete-trial" avoidance) was devised to differentiate between the two main theories of responding in Sidman's "free-operant" avoidance procedure. One theory, a version of two-factor theory, holds that responding is reinforced by the removal of a conditioned aversive stimulus. The conditioned aversive stimulus is held to be temporal, which accounts for the spaced responding, or timing, that Sidman's procedure produces. The other theory holds that the reinforcement for both responding and timing is shock-frequency reduction. The new procedure eliminated this reinforcement for timing, but retained the conditions for the formation of conditioned aversive temporal stimuli. According to one theory, the new procedure should have sustained timing as well as Sidman's, while according to the other, it should have sustained no timing. The results confirmed neither theory. Timing was found with both procedures, but unequally in degree and kind. Large variations in the precision of timing did not appear to be correlated with successful avoidance for either procedure.

Journal Article↗
PubMed1970

On the law of effect.

Experiments on single, multiple, and concurrent schedules of reinforcement find various correlations between the rate of responding and the rate or magnitude of reinforcement. For concurrent schedules (i.e., simultaneous choice procedures), there is matching between the relative frequencies of responding and reinforcement; for multiple schedules (i.e., successive discrimination procedures), there are contrast effects between responding in each component and reinforcement in the others; and for single schedules, there are a host of increasing monotonic relations between the rate of responding and the rate of reinforcement. All these results, plus several others, can be accounted for by a coherent system of equations, the most general of which states that the absolute rate of any response is proportional to its associated relative reinforcement.

Journal Article↗