家兔具有分辨红绿的色觉行为

本文在11只上海家免上进行了色觉行为学的实验研究。通过限制方位、光强等可能成为条件刺激的因素,并排除了声音、气味、背景光刺激等的干扰,确保颜色成为唯一的条件刺激,建立食物性红绿色觉分辨条件反射。经过适应、筛选、驯练和测试,在家兔上建立了对绿光稳固的条件反射。该结果显示兔具有颜色分辨能力。     

Teacher-control versus student-control over choice of task and reinforcement for students with severe behavior problems

Increasing self-control for students with severe disabilities is an important step toward normalization. The classroom is one setting in which opportunities for self-control can be created. The effects of teacher-control versus student-control over academic task and reinforcement selection were evaluated for three 11-to 13-year-old males with severe behavior problems. Under student-control conditions students were able to select rewards and tasks from lists generated by the teacher; in the teacher-control conditions, the teacher selected rewards and tasks but attempted to make similar selections to those made by the students. An alternating treatments design was implemented. In Phase 1, task completion was the target behavior; in Phase 2 task accuracy was the target behavior. Task performance improved when the student, rather than the teacher, had control over task assignments and choice of reinforcement. While either student control of reinforcement or student control of task assignment resulted in higher performance than did teacher-control, the most effective instructional situation was the two procedures combined. This effect was apparent even when students and teachers selected the same tasks and the same reinforcers. Implications for increasing student-control over some classroom decisions are discussed.deceased.     

Delay and number of food reinforcers: Effects on choice and latencies

Pigeons were given a choice between two identical-duration situations (terminal links of chain schedules). One terminal link of the choice pair provided two food deliveries, and the other provided five. The exact times of these food deliveries differed between the terminal links and were varied over conditions. A single response during the initial link gave immediate access to the corresponding terminal link. Forced trials, during which only one of the initial-link keys was lighted, were interspersed with choice trials during which both initial-link keys were lighted. Choice tended to favor whichever terminal link was correlated with the higher sum of the immediacies (i.e., the sum of the reciprocals of the delays to each of the reinforcers following the choice, with all delays measured from the choice). Latencies on forced trials and on choice trials also were related (negatively) to the sum of the immediacies. This correlation among response measures (choice and latencies) suggests that both measures are manifestations of the effect of conditioned reinforcement on response tendencies.     

Positive behavioral contrast when pigeons press treadles during multiple schedules

Pigeons were placed on multiple variable-interval 15-second variable-interval 15-second and on multiple variable-interval 15-second extinction schedules in which treadle presses produced food reinforcers. Positive behavioral contrast occurred. That is, rates of responding were higher during the variable-interval 15-second component when the other component was extinction than when it was another variable-interval 15-second schedule. These results contradict the findings of other studies, which failed to find positive contrast when pigeons pressed treadles for food reinforcers. They may also question the additive theories of behavioral contrast that predict that contrast should not occur in this situation.     

Response suppression by visual stimuli paired with postsession d-amphetamine injections in the pigeon

Responding of pigeons, maintained under a fixed-interval 3-minute schedule of food presentation, was decreased on days that the color of the lights illuminating the food magazine was changed and d-amphetamine (1.0 mg/kg, i.m.) was injected after the session. Responding was not decreased by keylight color changes paired with postsession d-amphetamine or by postsession injections of saline. Administration of pentobarbital (3.0 to 5.6 mg/kg), but not d-amphetamine (.3 to 3.0 mg/kg), before the session increased rates of responding suppressed by drug-paired magazine lights. Responding maintained under a fixed-ratio 30-response schedule was not decreased when differently colored magazine lights were paired with a low (.3 mg/kg) postsession dose of d-amphetamine; with high (3.0 mg/kg) postsession doses, however, responding was completely suppressed after two pairings. The effects of pairing magazine stimuli with an intermediate (1.0 mg/kg) postsession dose of d-amphetamine depended upon the magnitude of prior postsession doses. After being paired with a low dose, stimuli paired with 1.0 mg/kg did not suppress responding. After being paired with a high dose, stimuli paired with 1.0 mg/kg completely suppressed responding. The suppression of food-maintained responding by stimuli paired with postsession drug administration depends upon both behavioral and pharmacological variables.     

A response to "On token reinforcement and stuttering therapy: Another view on findings reported by Howie and Woods (1982)"

Ingham's (1983) critique of our research is based on the unwarranted assumption that it claimed to be a replication of Ingham and Andrews' (1973a) study. Our report did not claim to be a replication. Procedural differences between treatments do not preclude the possibility of drawing general conclusions that may apply to related treatments, or suggesting possible confounding variables that might be operating in another study. We have nevertheless dealt with each of Ingham's methodological objections. In general, we believe that we struck an acceptable compromise between the needs of clients and theoretical and research demands. We stand by our original conclusions, and note with satisfaction that Ingham concurs with our emphasis on systematic structure rather than the presence or absence of rewards as the crucial component of this type of stuttering treatment.     

THE EFFECTS OF ACCESS TO SPECIAL ACTIVITIES ON THE PERFORMANCE IN FOUR CATEGORIES OF ACADEMIC TASKS WITH THIRD-GRADE STUDENTS1

An ABAB experimental design was used to evaluate the effects of access to recreational activities contingent on the completion of at least 80% of academic tasks assigned daily. Requirements in four task categories (writing, copying words, spelling, and dictionary skills) were specified daily and students were required to complete at least 80% of the requirements in each category correctly in order to participate in daily recreational activities. The procedure produced reliable and educationally important increases in the task performance of all 19 third-grade students in the study. Most of the difference in the performance of each child between experimental conditions was on the spelling and dictionary tasks, although there were also improvements on the writing and words-copied tasks for those students showing the greatest overall change in performance. The procedure was easily implemented by the teacher alone, required only materials and equipment typically found in elementary schools, and produced changes in performance important enough to the teacher that she continued to use the basic procedure after the evaluation program was terminated.     

Conditioned reinforcement by conditional discriminative stimuli.

A concurrent-chains schedule was used to examine how a delay to conditional discriminative stimuli affects conditioned reinforcement strength. Pigeons' key-peck responses in the initial link produced either of two terminal links according to independent variable-interval 30-s schedules. Each terminal link involved an identical successive conditional discrimination and was segmented into three links: a delay interval (green), a color conditional discriminative stimulus (blue or red), and a line conditional discriminative stimulus (vertical or horizontal lines). Food delivery occurred 45 s after entering the terminal link with a probability of .5, but its conditional probability (1.0 or 0) depended on the combination of the color and the line stimuli. One of the color stimuli occurred independently of further responding, 5 s after entry into the right terminal link, but it occurred 35 s after entry into the left terminal link. One of the line stimuli occurred independently of responding 40 s after entry into either terminal link, synchronized with the offset of the color stimulus. The initial-link relative response rate for the right was consistently higher in comparison with a control condition in which the color stimuli occurred 20 s after entry into either terminal link. The preference for the short delay to the color conditional discriminative stimuli suggests the possibility of conditioned reinforcement by information about the relation between the line conditional discriminative stimuli and the outcomes.     

Control of behavior by an establishing stimulus

Seventeen pigeons were exposed to a three-key discrete-trial procedure in which a peck on the lit center key produced food if, and only if, the left keylight was lit. The center key was illuminated by a peck on the lit right key. Of interest was whether subjects pecked the right key before or after the response-independent onset of the left keylight. Pecks on the right key after left-keylight onset suggest control of behavior by the left keylight—an establishing stimulus. In three experiments, the strength of center-keylight onset as conditioned reinforcer for a response on the right key was manipulated by altering the size of the reduction in time to food delivery correlated with its onset. Control of pigeons' key pecks by onset of the left keylight occurred on more trials per session when the center keylight was a relatively weak conditioned reinforcer and on fewer trials per session when the center keylight was a relatively strong condtioned reinforcer. Differences across conditions in the degree of control by onset of the establishing stimulus were greatest when changes in conditioned reinforcer strength occurred relatively frequently and were signaled. The results provide evidence of the function of an establishing stimulus.     

Information on response requirements compared with information on food density as a reinforcer of observing in pigeons

On a variable-interval schedule, pecking the key to the pigeon's right (observing response) produced red or green displays relating to the delivery of grain and its dependence on pecking the key to the left (food key). During various blocks of sessions, mixed (no stimulus change) schedules including the following pairs of components were temporarily converted by the observing response to their corresponding multiple (correlated stimuli) schedules: variable-interval 60-s, extinction; variable-interval 60-s, variable-time (response-independent) 60-s; extinction, variable-time 60-s. Differences in food delivery maintained substantial rates of responding on the observing key, without regard to pecking requirements on the food key. Although stimuli correlated with differences in the response requirement on the food key maintained higher observing rates than those maintained by uncorrelated stimuli, they were much lower than those based on food. The value of predictive stimuli as reinforcers is determined by the value of the events predicted. In particular, the cost of pecking appears to be low, and this may place limitations on the applicability of energy-based and economic models of behavior.