Toward an animal model of type A behavior

Time estimation and dominance tests were used to differentiate the behavior of Mongolian gerbils to be analogous to Type A and Type B human behavior. Preliminary classification of animals as "Type A" or "B" was based upon differential performance on DRL 20-sec and DRL 60-sec reinforcement schedules. To retain their preliminary classification, Type A and Type B animals were required to be dominant and subordinate, respectively, in matches with each of three same-sex animals of opposite behavioral classification. Following classification, breeding pairs were constituted and classification procedures were repeated with two succeeding generations. Animals that exhibited Type A timing "won" significantly more dominance matches than did Type B animals. Incidence rates of Type A and Type B behavior in the two selectively bred generations were significantly greater than frequencies in the original stock generation. The usefulness of the present animal model for investigating the association of Type A behavior with coronary heart disease is discussed.     

Thorndike's Puzzle Boxes And The Origins Of The Experimental Analysis Of Behavior

The year of Thorndike's dissertation on animal intelligence, 1898, may mark the beginning of the field that eventually became known as the experimental analysis of behavior. The dissertation began a major shift in thinking about animal and human learning, provided important methodological innovations, and carried the seeds of later research and theory, particularly by B. F. Skinner. Although Thorndike was an associationist in 1898, the dissertation began the systematic search for fundamental behavioral processes, and laid the foundation for an empirical science of behavior.     

Effects of signaling on temporal control of behavior in response‐initiated fixed intervals

Behavior and events distributed in time can serve as markers that signal delays to future events. The majority of timing research has focused on how behavior changes as the time to some event, usually food availability, decreases. The primary objective of the two experiments presented here was to assess how behavior changes as time passes between two time markers when the first time marker was manipulated but the second, food delivery, was held constant. Pigeons were exposed to fixed‐interval, response‐initiated fixed‐interval, and signaled response‐initiated fixed‐interval 15‐ and 30‐s schedules of reinforcement. In Experiment 1, first‐response latencies were systematically shorter in the signaled response‐initiated schedules than response‐initiated schedules, suggesting that the first response was a more effective time marker when it was signaled. In Experiment 2, responding in no‐food (i.e. “peak”) trials indicated that timing accuracy was equivalent in the three schedule types. Compared to fixed interval schedules, timing precision was reduced in the signaled response‐initiated schedules and was lowest in response‐initiated schedules. Results from Experiments 1 and 2 coupled with previous research suggest that the overall “informativeness” of a time marker relative to other events and behaviors in the environment may determine its efficacy.     

Making and breaking habits: Revisiting the definitions and behavioral factors that influence habits in animals

Habits have garnered significant interest in studies of associative learning and maladaptive behavior. However, habit research has faced scrutiny and challenges related to the definitions and methods. Differences in the conceptualizations of habits between animal and human studies create difficulties for translational research. Here, we review the definitions and commonly used methods for studying habits in animals and humans and discuss potential alternative ways to assess habits, such as automaticity. To better understand habits, we then focus on the behavioral factors that have been shown to make or break habits in animals, as well as potential mechanisms underlying the influence of these factors. We discuss the evidence that habitual and goal-directed systems learn in parallel and that they seem to interact in competitive and cooperative manners. Finally, we draw parallels between habitual responding and compulsive drug seeking in animals to delineate the similarities and differences in these behaviors.     

时距知觉的动物研究范式及相关神经机制

在探索时距知觉的脑机制的过程中, 相对于人类被试相关研究, 动物研究可以提供较多的药理学、分子生物学、单个神经元电生理学以及光遗传等方面的研究证据。目前较为常用的时距知觉动物研究范式包括时间二分法、峰值间隔法以及低比率差别强化法等。根据不同的研究需求, 动物研究的范式常会进行调整。对时距知觉的动物研究的探讨将基于两方面展开：(1) 常用的时距知觉动物研究范式的介绍及比较; (2) 基于动物研究范式的时距知觉神经机制研究进展, 旨在为深入探索时间知觉的心理学相关研究提供参考。     

Recent reinforcement-schedule research and applied behavior analysis

Reinforcement schedules are considered in relation to applied behavior analysis by examining several recent laboratory experiments with humans and other animals. The experiments are drawn from three areas of contemporary schedule research: behavioral history effects on schedule performance, the role of instructions in schedule performance of humans, and dynamic schedules of reinforcement. All of the experiments are discussed in relation to the role of behavioral history in current schedule performance. The paper concludes by extracting from the experiments some more general issues concerning reinforcement schedules in applied research and practice.     

APPLIED IMPLICATIONS OF REINFORCEMENT HISTORY EFFECTS

Although the influence of reinforcement history is a theoretical focus of behavior analysis, the specific behavioral effects of reinforcement history have received relatively little attention in applied research and practice. We examined the potential effects of reinforcement history by reviewing nonhuman, human operant, and applied research and interpreted the findings in relation to possible applied significance. The focus is on reinforcement history effects in the context of reinforcement schedules commonly used either to strengthen behavior (e.g., interval schedules) or commonly used to decrease behavior (e.g., extinction).     

The conditions for temporal tracking under interval schedules of reinforcement

On many cyclic-interval schedules, animals adjust their postreinforcement pause to follow the interval duration (temporal tracking). Six pigeons were trained on a series of square-wave (2-valued) interval schedules (e.g., 12 fixed-interval [FI] 60, 4 FI 180). Experiment 1 showed that pigeons track square-wave schedules, except those with a single long interval per cycle. Experiments 2 and 3 established that tracking and nontracking are learned and both can transfer from one cyclic schedule to another. Experiment 4 demonstrated that pigeons track a schedule with a single short interval per cycle, suggesting that a dual process--cuing and tracking--is necessary to explain behavior on these schedules. These findings suggest a potential explanation for earlier results that reported a failure to track square-wave schedules.     

Behavioral economics and behavioral momentum

Some relations between elasticity of demand and the conditions of reinforcement are reanalyzed in terms of resistance to change, in ways suggested by the metaphor of behavioral momentum; some relations between resistance to change and the conditions of reinforcement are reanalyzed in terms of elasticity of demand, in ways suggested by behavioral economics. In addition, some data on labor supply in relation to variable-ratio schedules and alternative reinforcement are reanalyzed in terms of resistance to change and compared with steady-state resistance data for performance on multiple and concurrent interval schedules. The results of these studies can be summarized by two functions based on the behavioral momentum approach, relating relative behavioral mass to relative reinforcement per response or per unit time. The former is a relation between relative unit price and relative behavioral mass, suggesting the possibility of convergent measurement of a theoretical construct common to both approaches. However, the momentum and economic approaches differ fundamentally on whether it is preferable to construe discriminated operant behavior as selected and strengthened by its consequences or as part of a behavior–consequence bundle that maximizes utility.     

Hill-climbing by pigeons

Pigeons were exposed to two types of concurrent operant-reinforcement schedules in order to determine what choice rules determine behavior on these schedules. In the first set of experiments, concurrent variable-interval, variable-interval schedules, key-peck responses to either of two alternative schedules produced food reinforcement after a random time interval. The frequency of food-reinforcement availability for the two schedules was varied over different ranges for different birds. In the second series of experiments, concurrent variable-ratio, variable-interval schedules, key-peck responses to one schedule produced food reinforcement after a random time interval, whereas food reinforcement occurred for an alternative schedule only after a random number of responses. Results from both experiments showed that pigeons consistently follow a behavioral strategy in which the alternative schedule chosen at any time is the one which offers the highest momentary reinforcement probability (momentary maximizing). The quality of momentary maximizing was somewhat higher and more consistent when both alternative reinforcement schedules were time-based than when one schedule was time-based and the alternative response-count based. Previous attempts to provide evidence for the existence of momentary maximizing were shown to be based upon faulty assumptions about the behavior implied by momentary maximizing and resultant inappropriate measures of behavior.     

Effects of d-amphetamine, chlorpromazine, and chlordiazepoxide on intercurrent behavior during spaced-responding schedules.

Effects of d-amphetamine, chlorpromazine, and chlordiazepoxide on lever pressing under direct control of spaced-responding schedules were compared with effects on intercurrent drinking and wheel running in the rat. Drug effects on lever pressing were systematically related to dose and were consistent for all animals; drug effects on intercurrent behavior were generally different for each animal. In the case of lever presses, increasing doses of d-amphetamine first increased and then decreased response rate, increasing doses of chlorpromazine produced graded decreases in response rate, and doses of chlordiazepoxide up to 40 mg/kg produced no effect on response rate. These data are discussed in context with the concept of schedule control, and it is suggested that the behavioral pharmacology of intercurrent behavior be explored as a useful procedure in the experimental analysis of intercurrent behavior.     

LEARNING TO TIME: A PERSPECTIVE

In the last decades, researchers have proposed a large number of theoretical models of timing. These models make different assumptions concerning how animals learn to time events and how such learning is represented in memory. However, few studies have examined these different assumptions either empirically or conceptually. For knowledge to accumulate, variation in theoretical models must be accompanied by selection of models and model ideas. To that end, we review two timing models, Scalar Expectancy Theory (SET), the dominant model in the field, and the Learning‐to‐Time (LeT) model, one of the few models dealing explicitly with learning. In the first part of this article, we describe how each model works in prototypical concurrent and retrospective timing tasks, identify their structural similarities, and classify their differences concerning temporal learning and memory. In the second part, we review a series of studies that examined these differences and conclude that both the memory structure postulated by SET and the state dynamics postulated by LeT are probably incorrect. In the third part, we propose a hybrid model that may improve on its parents. The hybrid model accounts for the typical findings in fixed‐interval schedules, the peak procedure, mixed fixed interval schedules, simple and double temporal bisection, and temporal generalization tasks. In the fourth and last part, we identify seven challenges that any timing model must meet.     

Associative representational plasticity in the auditory cortex: a synthesis of two disciplines

Historically, sensory systems have been largely ignored as potential loci of information storage in the neurobiology of learning and memory. They continued to be relegated to the role of "sensory analyzers" despite consistent findings of associatively induced enhancement of responses in primary sensory cortices to behaviorally important signal stimuli, such as conditioned stimuli (CS), during classical conditioning. This disregard may have been promoted by the fact that the brain was interrogated using only one or two stimuli, e.g., a CS(+) sometimes with a CS(-), providing little insight into the specificity of neural plasticity. This review describes a novel approach that synthesizes the basic experimental designs of the experimental psychology of learning with that of sensory neurophysiology. By probing the brain with a large stimulus set before and after learning, this unified method has revealed that associative processes produce highly specific changes in the receptive fields of cells in the primary auditory cortex (A1). This associative representational plasticity (ARP) selectively facilitates responses to tonal CSs at the expense of other frequencies, producing tuning shifts toward and to the CS and expanded representation of CS frequencies in the tonotopic map of A1. ARPs have the major characteristics of associative memory: They are highly specific, discriminative, rapidly acquired, exhibit consolidation over hours and days, and can be retained indefinitely. Evidence to date suggests that ARPs encode the level of acquired behavioral importance of stimuli. The nucleus basalis cholinergic system is sufficient both for the induction of ARPs and the induction of specific auditory memory. Investigation of ARPs has attracted workers with diverse backgrounds, often resulting in behavioral approaches that yield data that are difficult to interpret. The advantages of studying associative representational plasticity are emphasized, as is the need for greater behavioral sophistication.     

Dynamics of waiting in pigeons

Two experiments used response-initiated delay schedules to test the idea that when food reinforcement is available at regular intervals, the time an animal waits before its first operant response (waiting time) is proportional to the immediately preceding interfood interval (linear waiting; Wynne & Staddon, 1988). In Experiment 1 the interfood intervals varied from cycle to cycle according to one of four sinusoidal sequences with different amounts of added noise. Waiting times tracked the input cycle in a way which showed that they were affected by interfood intervals earlier than the immediately preceding one. In Experiment 2 different patterns of long and short interfood intervals were presented, and the results implied that waiting times are disproportionately influenced by the shortest of recent interfood intervals. A model based on this idea is shown to account for a wide range of results on the dynamics of timing behavior.     

A Turing Test for Computational and Associative Theories of Learning

A Turing test is proposed to evaluate current computational and associative models of learning, and to guide theoretical developments. This test requires a specification of the procedures to which the model applies, a sampling of procedures and response measures, and an objective way to determine the difficulty of discriminating the responses of the model from the responses of the animal. Scalar timing theory is used as an example of a well-developed computational theory of timing that involves addition, multiplication, division, and sampling. The behavioral theory of timing is used as an example of a well-developed associative theory of timing that involves state transitions and strengthening of connections. A Turing test provides a way to evaluate such theories.     

Forebrain circuits and control of feeding by learned cues

Professor Richard F. Thompson and his highly influential work on the brain substrates of associative learning and memory have critically shaped my research interests and scientific approach. I am tremendously grateful and thank Professor Thompson for the support and influence on my research and career. The focus of my research program is on associative learning and its role in the control of fundamental, motivated behaviors. My long-term research goal is to understand how learning enables environmental cues to control feeding behavior. We use a combination of behavioral studies and neural systems analysis approach in two well-defined rodent models to study how learned cues are integrated with homeostatic signals within functional forebrain networks, and how these networks are modulated by experience. Here, I will provide an overview of the two behavioral models and the critical neural network components mapped thus far, which include areas in the forebrain, the amygdala and prefrontal cortex, critical for associative learning and decision-making, and the lateral hypothalamus, which is an integrator for feeding, reward and motivation.     

Role of nonreinforcement in the fixed-interval performance of pigeons

Fixed-interval (FI) schedules have been used extensively to study timing abilities. In FI schedules, animals typically show higher response rates immediately after nonreinforced (N) cycles rather than reinforced (R) cycles (the reinforcement-omission effect), and they exhibit the highest rate approximately at the time when the reinforcer is scheduled to occur (peak performance). The present experiments were designed to determine the extent to which factors other than timing contribute significantly to these two learning phenomena. Pigeons were trained in an FI 16-sec schedule in which half the cycles were R and half were N. When successive cycles were separated by a 2-sec interval, responding early in the FI interval was higher after an N cycle than after an R cycle. This reinforcement-omission effect was eliminated when the interval between cycles was increased to 12 sec, because of an increase in performance after R cycles. In addition, timing of the 16-sec interval was assessed by interpolating 32-sec test cycles (all N cycles) at two rates—either 1 test cycle every other session, or 25 test cycles per session. Peak performance, presumably indexing the animal’s ability to time the 16-sec interval, emerged only with 25 test cycles per day, but not with 1 test cycle every other day, despite extensive training with the target, 16-sec-long interval. These results suggest that transient demotivation and time-based discrimination contribute significantly to the reinforcement-omission effect and peak performance, respectively.     

The human side of animal behavior

An important element of behavioral research with nonhuman animals is that insights are drawn from it about human behavior, what is called here the human side of animal behavior. This article examines the origins of comparing human behavior to that of other animals, the ways in which such comparisons are described, and considerations that arise in evaluating the validity of those comparisons. The rationale for such an approach originated in the reductionism of experimental physiology and the understanding of the commonalities of all life forms promulgated by Darwinian evolutionary biology. Added more recently were such observations as the relative simplicity of animal behavior, tempered by the constraints placed on resulting comparisons by the absence of verbal behavior in animals. The construction of comparisons of human behavior to that of animals may be framed on the basis of Skinner's (1957) distinction between the metaphorical and generic forms of the extended tact. Both ordinary and systematic comparisons of animal and human behavior are congruent with Skinner's extended tact framework. The most general consideration in evaluating comparisons of animal and human behavior is that a functional basis for the claimed similarity be established. Systematic analysis and convergent evidence also may contribute to acceptability of these comparisons. In the final analysis, however, conclusions about the human side of animal behavior are nondeductively derived and often are assessed based on their heuristic and pragmatic value. Such conclusions represent a valuable contribution to understanding the human animal and in developing practical solutions to problems of human behavior to which much of psychology is dedicated.     

Concurrent variable‐interval variable‐ratio schedules in a dynamic choice environment

Most studies of operant choice have focused on presenting subjects with a fixed pair of schedules across many experimental sessions. Using these methods, studies of concurrent variable‐ interval variable‐ratio schedules helped to evaluate theories of choice. More recently, a growing literature has focused on dynamic choice behavior. Those dynamic choice studies have analyzed behavior on a number of different time scales using concurrent variable‐interval schedules. Following the dynamic choice approach, the present experiment examined performance on concurrent variable‐interval variable‐ratio schedules in a rapidly changing environment. Our objectives were to compare performance on concurrent variable‐interval variable‐ratio schedules with extant data on concurrent variable‐interval variable‐interval schedules using a dynamic choice procedure and to extend earlier work on concurrent variable‐interval variable‐ratio schedules. We analyzed performances at different time scales, finding strong similarities between concurrent variable‐interval variable‐interval and concurrent variable‐interval variable‐ ratio performance within dynamic choice procedures. Time‐based measures revealed almost identical performance in the two procedures compared with response‐based measures, supporting the view that choice is best understood as time allocation. Performance at the smaller time scale of visits accorded with the tendency seen in earlier research toward developing a pattern of strong preference for and long visits to the richer alternative paired with brief “samples” at the leaner alternative (“fix and sample”).     

Assessing reinforcers under progressive schedule requirements.

Recent research findings suggest that reinforcing stimuli may be differentially effective as response requirements increase. We extended this line of research by evaluating responding under increasing schedule requirements via progressive‐ratio schedules and behavioral economic analyses. The differential effectiveness of preferred stimuli in treating destructive behavior maintained by automatic reinforcement also was examined. Results showed that one of two stimuli was associated with more responding under increasing schedule requirements for the 4 participants. Furthermore, stimuli associated with more responding under increasing schedule requirements generally were more effective in treating destructive behavior than stimuli associated with less responding. These data suggest that progressive‐ratio schedules and behavioral economic analyses may be useful for developing a new technology for reinforcer identification. From a clinical perspective, these results suggest that two reinforcers may be similarly effective for low‐effort tasks and differentially effective for high‐effort tasks.