摘要:

Pigeons were trained on a series of reversals of a simultaneous form discrimination in which the trial outcomes were separated from the choice responses by an 8‐s delay interval. Different conditions were defined by the stimuli occurring during the two halves of the delay interval. Discrimination learning was greatly facilitated by having differential stimuli during the delay following correct versus incorrect choices. When the differential stimuli appeared only at the midpoint of the delay, some facilitation occurred relative to when no different stimuli occurred, but there was substantially less facilitation than when the differential stimuli occurred immediately contingent on choice. A reversed‐stimulus condition, in which the stimulus at the onset of the delay following a correct choice was the same as that during the last segment of the delay following an incorrect choice, and the stimulus at the onset of the delay following an incorrect choice was the same as that preceding food during the last segment of the delay following a correct choice, also facilitated discrimination learning relative to the nondifferential stimulus conditi

ISSN:0022-5002    

DOI:10.1901/jeab.1994.62-157

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Rats in a laboratory foraging paradigm searched for sequential opportunities to drink in two water patches that differed in the bar‐press price of each “sip” (20 licks) of water within a bout of drinking (Experiment 1) or the price and size (10, 20, or 40 licks) of each sip (Experiment 2). Total daily water intake was not affected by these variables. The rats responded faster at the patch where water was more costly. However, they accepted fewer opportunities to drink, and thus had fewer drinking bouts, and drinking bouts were smaller at the more costly patch than at the other patch. This resulted in the rats consuming a smaller proportion of their daily water from the more costly patch. The size of the differences in bout frequency and size between the patches appears to be based on the relative cost of water at the patches. The profitability of each patch was calculated in terms of the return (in milliliters) on either effort (bar presses) or time spent there. Although both measures were correlated with the relative total intake, bout size, and acceptance of opportunities at each patch, the time‐based profitability was the better predictor of these intake measures. The rats did not minimize bar‐press output; however, their choice between the patches and their bout sizes within patches varied in a way that reduced costs compared to what would have been expended drinking randomly. These data accord well with similar findings for choices among patches of food, suggesting that foraging for water and food occurs on the basis of comparable benefit‐cost functions: In each case, the amount consumed is related to the time spen

ISSN:0022-5002    

DOI:10.1901/jeab.1994.62-169

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Five pigeons were trained in an analogue foraging procedure in which, by completing a travel requirement, they entered a “patch” in which a reinforcer might be available after an unpredictable time. They also had the opportunity, by emitting a defined response, to exit the patch and travel to another patch. Prey availability in a patch was not signaled. Data were collected on the length of time that subjects stayed in patches before exiting (residence times) as a function of various travel requirements: travel for a fixed time in blackout, fixed‐interval schedule traveling, fixed‐time traveling with an added response required to terminate traveling, and fixed‐ratio traveling. For each of these conditions, the required amount of travel (time or responses) was varied over a wide range. As previously reported, residence times increased with increases in fixed‐time traveling, as they did with increasing fixed‐interval or fixed‐ratio traveling. There was no evidence that adding response or work requirements systematically affected residence time except via increased travel time, although 3 of the 5 birds stayed longer in a patch under higher fixed‐ratio values. A “threshold‐maximization” model described the data well with a single parameter that was consistent across subjects, proc

ISSN:0022-5002    

DOI:10.1901/jeab.1994.62-185

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

The pigeon's key‐pecking response is experimentally dissociable into transport (head movement) and gape (jaw movement) components. During conditioning of the key‐pecking response, both components come under the control of the conditioned stimulus. To study the acquisition of gape conditioned responses and to clarify the contribution of unconditioned stimulus (reinforcer) variables to the form of the response, gape and key‐contact responses were recorded during an autoshaping procedure and reinforcer properties were systematically varied. One group of 8 pigeons was food deprived and subgroups of 2 birds each were exposed to four different pellet sizes as reinforcers, each reinforcer signaled by a keylight conditioned stimulus. A second group was water deprived and received water reinforcers paired with the conditioned stimulus. Water‐ or food‐deprived control groups received appropriate water or food reinforcers that were randomly delivered with respect to the keylight stimulus. Acquisition of the conditioned gape response frequently preceded key‐contact responses, and gape conditioned responses were generally elicited at higher rates than were key contacts. The form of the conditioned gape was similar to, but not identical with, the form of the unconditioned gape. The gape component is a critical topographical feature of the conditioned key peck, a sensitive measure of conditioning during autoshaping, and an important source of the observed similarities in the form of conditioned and consummator

ISSN:0022-5002    

DOI:10.1901/jeab.1994.62-201

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Choice responding by adult humans in a discrete‐trial task was examined as a function of conditions that manipulated either the delay to point delivery or the delay between points and their exchange for money. In point‐delay conditions, subjects chose between an “impulsive” alternative that provided a small amount of points immediately and a “self‐control” alternative that provided a larger amount of points delayed by 15, 30, or 60 s. Points were exchanged for money immediately following the session. Subjects preferred the self‐control alternative. In exchange‐delay conditions, subjects chose between a small amount of points exchangeable for money immediately following the session and a larger amount of points exchangeable for money after 1 day, 3 weeks, or 6 weeks. A self‐control preference observed for all subjects in the 1‐day exchange‐delay condition reversed to exclusive impulsive preference for 4 of the 6 subjects when choice conditions involved exchange delays of 3 or 6 weeks. These results show that human choice is sensitive to the manipulation of exchange delays and that impulsive preference can be obtained with exchange delay

ISSN:0022-5002    

DOI:10.1901/jeab.1994.62-225

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Two experiments examined apparent signal probability effects in simple verbal self‐reports. After each trial of a delayed matching‐to‐sample task, young adults pressed either a “yes” or a “no” button to answer a computer‐presented query about whether the most recent choice met a point contingency requiring both speed and accuracy. A successful matching‐to‐sample choice served as the “signal” in a signal‐detection analysis of self‐reports. Difficulty of matching to sample, and thus signal probability, was manipulated via the number of nonmatching sample and comparison stimuli. In Experiment 1, subjects exhibited a bias (logb) for reporting matching‐to‐sample success when success was frequent, and no bias or a bias for reporting failure when success was infrequent. Contingencies involving equal conditional probabilities of point consequences for “I succeeded” and “I failed” reports had no systematic effect on this pattern. Experiment 2 found signal probability effects to be evident regardless of whether referent‐response difficulty was manipulated in different conditions or within sessions. These findings indicate that apparent signal probability effects in self‐report bias that were observed in previous studies probably were not an artifact of contingencies intended to improve self‐report accuracy or of the means of manipulating signal probability. The findings support an analogy between simple self‐reports and psychophysical judgments and bolster the conclusion of Critchfield (1993) that signal probability effects can influence simple self‐reports much as they do reports abo

ISSN:0022-5002    

DOI:10.1901/jeab.1994.62-235

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

The present study tested the idea that human self‐discrimination response functions may transfer through equivalence relations. Four subjects were trained in six symbolic matching‐to‐sample tasks (if see A1, choose B1; A1‐C1, A2‐B2, A2‐C2, A3‐B3, A3‐C3) and were then tested for the formation of three equivalence relations (B1‐C1, B2‐C2, B3‐C3). Two of the B stimuli (B1 and B2) were then used to train two different self‐discrimination responses using either detailed instructions (Subjects 1 to 3) or minimal instructions (Subject 4) on two complex schedules of reinforcement (i.e., subjects were trained to pick the B1 stimulus if they had not emitted a response, and to pick the B2 stimulus if they had emitted one or more responses on the previous schedule). All 4 subjects showed the predicted transfer of self‐discrimination response functions through equivalence relations (i.e., no response on the schedule, pick C1; one or more responses on the schedule, pick C2). Subjects also demonstrated this transfer when they were required to discriminate their schedule performancebeforeexposure to the schedule (i.e., “what I intend to do”). Four control subjects were also used in the study. Two of these (Subjects 5 and 6) were not exposed to any form of matching‐to‐sample training and testing (nonequivalence controls). The 2 remaining subjects (7 and 8) were exposed to matching‐to‐sample training and testing that incorporated stimuli not used during the transfer test; C1 and C2 were replaced by N1 and N2 during the matching‐to‐sample training and testing, but C1 and C2 were used for the transfer tests (equivalence controls). All 4 subjects failed to produce the self‐discrimination transfer performan

ISSN:0022-5002    

DOI:10.1901/jeab.1994.62-251

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Based on the delay‐reduction hypothesis, a less profitable schedule should be rejected if its duration exceeds the mean delay to reinforcement. It should be accepted if its duration is shorter than the mean delay. This was tested for humans, using a successive‐choice schedule. The accessibility of the less profitable (variable‐interval 18 s) schedule was varied by changing the duration (in terms of a fixed interval) of the waiting‐time component preceding its presentation. Forty‐eight students were randomly assigned to three groups. In Phase 1, the duration of the less profitable schedule equaled the mean delay to reinforcement in all groups. In Phase 2, waiting time preceding the less profitable schedule was reduced in Group 1 and increased in Group 2. Thus, the schedule was correlated either with a relative delay increase (Group 1) or a delay reduction (Group 2). In Group 3, conditions remained unchanged. As predicted, acceptance of the less profitable schedule decreased in Group 1 and increased in Group 2. The increased acceptance in Group 2 was accompanied by a decreased acceptance of the more profitable (variable‐interval 3 s) schedule, resembling a pattern of negative contrast. Response rates were higher under the component preceding (a) the more profitable schedule in Group 1 and (b) the less profitable schedule in Group 2. Implications for the modification of human choice behavior ar

ISSN:0022-5002    

DOI:10.1901/jeab.1994.62-269

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

In a study examining “demand” for food, responding of 8 adult male baboons (Papio c. anubis) was maintained under a fixed‐ratio schedule of food reinforcement during daily 23‐hr experimental sessions. Completion of the ratio requirement resulted in the delivery of one, five, or 10 1‐g food pellets. Supplemental feeding was limited to fruit and a dog biscuit daily. Responding increased as “cost” was increased across a wide range of fixed‐ratio values before reaching a maximum and then decreasing. Increasing the number of food pellets per delivery decreased total responding and the number of reinforcements per day. A unit‐price analysis, in which intake was converted to grams per day and fixed‐ratio values were converted to responses per gram, yielded demand functions that overlapped at lower unit prices. Under one or more multiple‐pellet conditions, however, intake decreased more quickly than under the one‐pellet condition as the fixed‐ratio value was increased in all but 1 baboon. This indicates that even when using unit‐price conversions, there was variability in total intake. Although unit‐price conversions yielded intake data that were more consistent across conditions, conditions differed in response topography even at the same unit prices: Under the multiple‐pellet conditions there were longer pauses in responding, running response rate was slower, and the first eating bout (i.e., “meal”) of the session was smaller than under the one‐pellet condition. These findings (a) support the heuristic value of a unit‐price analysis for studying responding for and consumption of commodities that have similar attributes, and (b) indicate that different response topographies may r

ISSN:0022-5002    

DOI:10.1901/jeab.1994.62-293

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Three rats, lever pressing for food delivered on a fixed‐interval 128‐s schedule, were presented with a 16‐s opportunity to drink from a retractable water source. The temporal placement of the water probe within the reinforcement cycle was varied sequentially, in steps of 16 s. Although the lever‐pressing pattern was modulated by the intercalated water probe, water consumption during the probe itself was a decreasing function of time from the following reinforcer. These results were interpreted as evidence against the notion that schedule‐induced drinking is a “ubiquitous” phenomenon and are congruent with results from other “intruded stimul

ISSN:0022-5002    

DOI:10.1901/jeab.1994.62-307

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY