摘要:

In studies of stimulus compounding (1) the stimuli are presented randomly, (2) primary reinforcement is correlated with each stimulus, (3) a specific response is emitted during each stimulus, and (4) the response is necessary to produce the reinforcer. The present experiments assessed the importance of these procedures by (1) presenting light and tone stimuli in fixed order, (2) removing reinforcement (food) during one stimulus, (3) preventing the response (lever pressing) from being emitted, and (4) eliminating the contingency between lever pressing and food. These variables were presented in various combinations within the context of chained and multiple schedules. When the stimuli were combined in the schedule component correlated with each stimulus, the frequency of lever pressing increased in most instances (additive summation). This suggests that the effect of combining stimuli was not closely tied to the specific procedures used in previous experiments. However, presenting the stimuli in a fixed order did have an effect: the level of responding to the compound was generally greatest when the stimuli were combined in the component correlated with the higher frequency of lever pressing to the single stimulus. Additive summation failed to occur consistently when response‐independent food was correlated with each stimulus, and when both lever pressing and food were eliminated during one stimulu

ISSN:0022-5002    

DOI:10.1901/jeab.1975.23-95

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

Three pigeons key pecked under second‐order schedules in which the completion of two successive fixed‐ratio 50 components constituted a reinforcement cycle. Tandem, chained, and brief‐stimulus second‐order schedules were studied when completion of the initial fixed‐ratio 50 component delivered brief intense electric shock in every nth reinforcement cycle andnassumed values between one and nine. During sessions without shock, the brief‐stimulus (unpaired with food) schedule generated higher rates of responding in the initial component than did the tandem schedule. Electric shock engendered increased time to the fifth response and a repeated pause‐run pattern of not responding and responding, particularly in the initial component, even with shock scheduled in every ninth reinforcement cycle. The results were consistent with those reported for shock of a shorter duration scheduled in every reinforcement cycle. The overall rate of responding decreased as a function of increasing shock density and was lower in brief‐stimulus than in t

ISSN:0022-5002    

DOI:10.1901/jeab.1975.23-103

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

Four rats were trained in darkness on a free‐operant avoidance procedure in which shocks occurred randomly, but lever presses could reduce their frequency. Discrimination training followed, during which responses in light continued to reduce shock frequency, but responses in darkness had no effect. During each cycle, the light period was 4 min, while darkness lasted only until a 20‐sec interval had elapsed without a response. This no‐response requirement was increased to 40 sec for three animals and eventually to 60 sec for two of them. Discriminative control developed, despite a greater shock density in the dark, with response rate and number of responses per shock maintained or increasing during light and decreasing to very low values in darkness. Two animals were later exposed to a procedure in which shock density was unaffected by responding either in light or darkness. A 60‐sec no‐response requirement was continued in the dark. Discriminative control persisted through 42 sessions for one animal and required 45 sessions to approach extinction for the other animal. The role of the light as a potential conditioned reinforcer of other behavior in the dark was implicated in the development and persistence of discriminative control. These data support shock‐frequency reduction as reinforcement for avoidan

ISSN:0022-5002    

DOI:10.1901/jeab.1975.23-111

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

Seven pigeons were trained to discriminate without errors between a green keylight and a dark key. The key‐pecking response was reinforced in the presence of green, and extinction was in effect in the presence of the dark key. The opportunity to attack a restrained target pigeon was present only during extinction. Both variable‐interval 30‐sec and fixed‐ratio 1 schedules of reinforcement during the positive stimulus induced a higher rate of attack during extinction than a variable‐interval 5‐min schedule. The highest rate of attack during extinction occurred during the first 20 sec after the positive stimulus terminated. Hence, the withdrawal of the positive condition, rather than the consequences of the pecking response during extinction, appears to be one of the primary factors responsible for attack between pigeons during extinction. Behavioral contrast, denned as a decrease in the rate of responding when the positive stimulus was presented alone, was obtained from the four birds that displayed the lowest overall rates of attack, while the three birds with the highest attack rates did not display behavioral contrast. For the birds without contrast, components of the attack response during the positive stimulus presumably competed with and reduced the rate of pecking the key, thereby precluding behavior

ISSN:0022-5002    

DOI:10.1901/jeab.1975.23-121

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

During the extinction component of a multiple variable‐interval extinction schedule, four pigeons learned to peck a second key that switched off the keylights. Two experiments attempted to isolate the events that control this behavior. In the first experiment, switching into blackout was equally maintained when switches were restricted to the first minute as when they were restricted to the last minute of the extinction component. When switches could be emitted in the first and last minutes, they occurred more frequently in the first. Restricting switching to the first minute of each component and eliminating the blackout between components had no effect on switching. In the second experiment, when the stimulus correlated with extinction was omitted, switching decreased slightly. Omission of both multiple schedule stimuli decreased the switching rate, but switching was still maintained. Food reinforcement was then omitted and switching by two birds increased. Switching ceased when blackout was no longer the consequence of pecking the switching key. It was concluded that switching was not controlled by the similarity of the blackouts produced by the switching key and those that occurred between components; nor was it maintained by the temporal proximity of switching responses to the onset of the reinforced component. Finally, switching did not appear to be controlled by the main‐key stimuli correlated with the components of the multiple sched

ISSN:0022-5002    

DOI:10.1901/jeab.1975.23-131

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

ISSN:0022-5002    

DOI:10.1901/jeab.1975.23-139

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

It is difficult to maintain stimulus control in animal psychophysical studies using the tracking method. Loss of stimulus control is characterized by wandering thresholds and responses in the absence of the stimulus. Rats were trained to make a variable number of licking responses to turn on an auditory stimulus. A response on a lever in the presence of the stimulus was reinforced with food. Two procedures were added to improve stimulus control. First, lever responses in the absence of the stimulus raised the intensity of the stimulus at the next presentation; second, rate of reinforcement in the threshold region was maintained at about the same level as that in the suprathreshold region by reducing the number of licking responses required to turn on the stimulus. Using these two procedures, stimulus control was improved and maintained and reliable auditory intensity thresholds were obtained.

ISSN:0022-5002    

DOI:10.1901/jeab.1975.23-141

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

Brown's book is selectively reviewed with the aim of noting points of similarity between Brown's psycholinguistic analysis of language acquisition and a functional analysis of verbal behavior. Brown divides early language acquisition into five stages, based on mean length of utterance in samples of child speech. His book concentrates on Stage I, when mean length of utterance first rises above 1.0, indicating that children are beginning to speak in multi‐morphemic utterances, and Stage II, when mean length of utterance in morphemes is about 2.25. Multi‐morphemic utterances in Stage I consist mainly of ordered sequences of uninflected nouns and verbs, the order being that of the simple declarative sentence (agent‐action‐indirect object‐direct object‐locative). The review attempts a theoretical analysis of the functional stimulus control of Stage I syntactic order, concluding that the control must originate partly in relations among events in the environment and partly in covert autoclitic verbal behavior. Increases in mean length of utterance in Stage II are mainly due to the appearance of several “grammatical morphemes” such as the progressive‐inginflection on verbs and the plural‐sinflection on nouns. The review attempts a behavioral paraphrase, again in terms of tacts and autoclitics, of Brown's psycholinguistic analysis of grammatical morphemes, concluding that Stage II displays the further development, building on Stage I, of the combined control of verbal behavior by relations in the environment and covert self‐generated verbal stimuli. Similarities between Brown's psycholinguistic analysis and a functional analysis of language acquisition suggest that the two viewpoints are converging on a common concern with the stimulus contr

ISSN:0022-5002    

DOI:10.1901/jeab.1975.23-149

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY