Independence of stimulus discriminability from absolute rate of reinforcement in a signal-detection procedure.

Three experiments are reported in which two pigeons were trained to detect differences in stimulus duration under varying levels of absolute rate of reinforcement. Two red stimuli, differing in duration, were arranged probabilistically on the center key of a three-key chamber. On completion of the center-key duration, the center keylight was extinguished and the two side keys were illuminated white. Correct responses were left-key pecks following the shorter duration and right-key pecks following the longer duration. In Experiment 1, relative rate of reinforcement for correct responses was held constant and absolute rate of reinforcement was varied in seven conditions from continuous reinforcement to a variable-interval 90-second schedule. In Experiment 2, relative rate of reinforcement was manipulated across three different absolute rates of reinforcement (continuous reinforcement, variable-interval 15-second, and variable-interval 45-second). Stimulus discriminability was unaffected by changes in absolute or relative rates of reinforcement. Experiment 3 showed that discriminability was also unaffected by arranging the same consequences (three-second blackout) for unreinforced correct responses and errors.     

Mirror pecking and timeout under a multiple fixed-ratio schedule of food delivery

Pigeons were trained to peck a key under a multiple fixed-ratio 25 fixed-ratio 175 schedule of food presentation. In the first condition, either a mirror or the opportunity to produce a 30-second timeout were available. In a second condition, mirror and timeout availability were reversed for the two groups. Following a return to the initial condition, mirror and timeout keys were presented together for all birds. Mirror and timeout responses occurred predominantly in the pause in the larger fixed-ratio component, regardless of whether the opportunities for the two responses were available singly or together. Mirror responding occurred in a greater proportion of the pauses than did timeouts. When the opportunities for both mirror pecking and timeout were available concurrently, they occurred with probabilities similar to those under the single conditions. Within the pause itself, mirror responses most frequently occurred immediately after reinforcement. Timeouts occurred most frequently toward the end of the pause, and some timeouts occurred in the early part of the run. Longer preratio pausing occurred in the larger fixed-ratio component in the conditions in which the mirror was present, whether or not any mirror pecks were recorded.     

Independence of sensitivity to relative reinforcement rate and discriminability in signal detection.

Six pigeons were trained to detect differences between two white stimuli, S1 and S2, differing in duration and arranged probabilistically on the center key of a three-key chamber. Detection performance was measured at two levels of discriminability. At one level, S1 was five seconds and S2 was thirty seconds. At the other level, S1 was twenty seconds and S2 was thirty seconds. The procedure was a standard signal-detection yes-no design in which stimulus-presentation probability was varied from .1 to .9 at both discriminability levels. On completion of the center-key stimulus, a peck on the center key darkened the center-key light and turned on the two red side keys. A left-key response was "correct" on S1 trials, and a right-key response was "correct" on S2 trials. Correct responses produced food reinforcement on a variable-ratio 1.3 schedule. Incorrect responses produced three second blackout. Discriminability was higher for the five-second versus thirty-second conditions than for the twenty-second versus thirty-second conditions, but there were no differences in sensitivity of behavior to reinforcement variation for the two stimulus pairs. Response bias was a function of the relative reinforcement rate for correct choice responses.     

Alternative reinforcement effects on fixed-interval performance

Pigeons' key pecks were reinforced with food on a fixed-interval schedule. Food also was available at variable time periods either independently of responding or for not key pecking (a differential-reinforcement-of-other-behavior schedule). The latter condition arranged reinforcement following the first pause of t seconds after it became available according to a variable-time schedule. This schedule allowed separation of the effects of pause requirements ≤ five-seconds and reinforcement frequency. The time spent pausing increased as the duration of the pause required for reinforcement increased from 0 to 30 seconds and as the frequency of reinforcement for pausing increased from 0 to 2 reinforcers per minute. Key pecking was more evenly distributed within each fixed interval with shorter required pauses and with more frequent reinforcement for pausing. The results complement those obtained with other concurrent schedules in which the same operant response was reinforced in both components.     

The role of contingencies and "principles of behavioral variation" in pigeons' pecking

Staddon and Simmelhag's proposal that behavior is produced by “principles of behavioral variation” instead of contingencies of reinforcement was tested in two experiments. In the first experiment pigeons were exposed to either a fixed-interval schedule of response-contingent reinforcement, an autoshaping schedule of stimulus-contingent reinforcement, or a fixed-time schedule of noncontingent reinforcement. Pigeons exposed to contingent reinforcement came to peck more rapidly than those exposed to noncontingent reinforcement. Staddon and Simmelhag's “principles of behavioral variation” included the proposal that patterns (interim and terminal) were a function of momentary probability of reinforcement. In the second experiment pigeons were exposed to either a fixed-time or a random-time schedule of noncontingent reinforcement. Pecking showed a constant frequency of occurrence over postfood time on the random-time schedule. Most behavior showed patterns on the fixed-time schedule that differed in overall shape (i.e., interim versus terminal) from those shown on the random-time schedule. It was concluded that both the momentary probability of reinforcement and postfood time can affect patterning.     

内隐序列学习意识的具身机制

内隐序列学习意识已有三类理论如全局工作平台理论、神经可塑性理论、新异刺激理论都忽略了身体感受的关键因素, 难以揭示意识产生的根本原因。具身意识理论和研究发现, 运动/情感镜像神经元系统及与自我、认知控制系统的交互, 是初级/高级意识产生的本源, 但未涉及内隐序列学习规则意识这个对人类学习认知至关重要的领域。内隐序列学习研究实质上已接近揭示其学习机制正是感知觉运动具身学习, 其意识机制很可能是感知觉运动/情感具身意识, 并且其意识加工脑区与具身意识脑区有关键重合。未来研究可采用Granger因果大脑网络技术证明内隐序列学习意识的具身本源, 并考察已有三类意识理论的具身基础, 以及探索意识影响因素的具身机制。     

镜像神经元:认知具身性的神经生物学证据

传统认知心理学认为认知类似于计算机对抽象符号的加工和运算,这种观点支持了身心二元论。但是近年来兴起的具身认知运动却否定了这一观点的合理性。具身认知认为认知是身体与世界互动的结果,是身体的感觉-运动系统作用于世界而塑造出来的。认知是具身的,离不开身体的构造和感觉运动系统的作用。镜像神经元的发现支持了认知的具身特征,为认知的具身性提供了神经生物学的证据。     

Acquisition and maintenance of autoshaped key pecking as a function of food stimulus and key stimulus similarity.

The results of a number of recent studies suggest that acquisitions of autoshaped key pecking in pigeons is affected by the similarity of the grain-hopper stimulus and response-key stimulus. In Experiment 1 this hypothesis was tested by training independent groups of pigeons to key peck under six different hopper-stimulus and key-stimulus similarity conditions, and three procedures containing either immediate reinforcement, variable delay of reinforcement, or omission of reinforcement for key pecking. Number of trials to acquisition was found to be related to the similarity variable. Maintained responding was affected by the response-reinforcer contingency. This effect was found both within and between subjects. Under two of the contingencies (automaintenance and omission), maintained responding continued to be affected by the similarity of the hopper stimulus and key stimulus. In Experiment 2 pigeons were given omission training with a hopper light on or off. Both acquisition and maintenance of key pecking were facilitated by the presence of the hopper light. The present findings suggest that much of the responding reported in various automatic shaping and training procedures may reflect the effects of key stimulus/food stimulus similarity.