摘要:

Two groups of experimentally naive pigeons were exposed to an autoshaping procedure in which the response key was mounted on the wall (the conventional location) or on the floor of the chamber. In two experiments, subjects readily responded to the wall key, but floor‐key subjects required shaping. A subsequent experiment compared performance of wall‐ and floor‐key groups on an ascending series of fixed‐ratio schedule values, resistance to extinction, differential reinforcement of other behavior, and reversal of key assignment. Each experiment was followed by several sessions of fixed‐ratio training; the performance of the wall‐ and floor‐key groups was almost identical throughout. In the final experiment, a fixed‐ratio requirement could be completed on either or both keys. Birds initially chose the key on which they had responded during the preceding (reversal of key assignment) experiment. However, within a few sessions both groups showed almost exclusive preference for the floor key. Preference for a key located on the floor may follow from the fact that pigeons are ground feeders and may thus be more “prepared” to peck the floor than to peck a wall. However, autoshaping, under the conditions prevailing here, occurred much more readily to the wall key, suggesting that pecking a vertical surface is more highly prepared. Difficulties in determining relative preparedness seem moot, however, given the lack of between‐group differences in the intervening experiments. It is thus unlikely that schedule performances critically depend upon the specific oper

ISSN:0022-5002    

DOI:10.1901/jeab.1992.58-399

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Economic theory predicts an inverse relationship between the quantity of a commodity supplied to the marketplace and the equilibrium market price of that commodity. This prediction was tested in three experiments. Pigeons responded on simple variable‐interval schedules, and quantity of reinforcement supplied was varied in a different way in each experiment. In Experiment 1, quantity supplied was varied by manipulating reinforcement rate while keeping session length constant. In Experiment 2, quantity supplied was varied by manipulating reinforcement rate while keeping reinforcers per session constant. In Experiment 3, quantity supplied was varied by manipulating reinforcer magnitude while keeping number of reinforcers constant. As predicted by economic theory, the obtained behavioral cost (responses per reinforcer) increased as supply decreased. The results could not be explained by simple artifacts such as satiation and time available to respond. In addition, the function relating response rate to reinforcement rate was bitonic in 7 of 9 animals in Experiments 1 and 2, which supports economic and regulatory theories over more traditional reinforcement theorie

ISSN:0022-5002    

DOI:10.1901/jeab.1992.58-415

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

The present study examined the acquisition of lever pressing in rats under three procedures in which food delivery was delayed by 4, 8, and 16 seconds relative to the response. Under the nonresetting delay procedure, food followed the response selected for reinforcement after a specified interval elapsed; responses during this interval had no programmed effect. Under the resetting procedure, the response selected for reinforcement initiated an interval to food delivery that was reset by each subsequent response. Under the stacked delay procedure, every response programmed delivery of foodtseconds after its occurrence. Two control groups were studied, one that received food immediately after each lever press and another that never received food. With the exception of the group that did not receive food, responding was established with every procedure at every delay value without autoshaping or shaping. Although responding was established under the resetting delay procedure, response rates were generally not as high as under the other two procedures. These findings support the results of other recent investigations in demonstrating that a response not previously reinforced can be brought to strength by delayed reinforcement in the absence of explicit training.

ISSN:0022-5002    

DOI:10.1901/jeab.1992.58-431

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Six pigeons responded on two concurrently available keys that defined patches with the following characteristics. Reinforcer stores repleted on a patch as a linear function of time when the bird had last responded to the other patch, or else did not replete. Repletion schedules thus timed only when the bird was absent from the patch. Reinforcer stores on a patch could be depleted and reinforcers obtained, again as a linear function of time, when the bird responded on a key. Depletion schedules thus timed only when the birds were present at a patch. Experiment 1 investigated changing relative depletion rates when repletion rates were constant and equal (Part 1) and changing relative repletion rates when the depletion rates were constant and equal (Part 2). Response‐ and time‐allocation ratios conformed to a generalized matching relation with obtained reinforcer ratios, and there appeared to be no control by the size of the reinforcer stores. In Experiment 2, absolute depletion rates were varied with a pair of unequal repletion rates (Part 3), and absolute repletion rates were varied with a pair of unequal depletion rates (Part 4). Dwell times in the patches were not affected by either variation. Melioration theory predicted the results of Experiment 1 quite closely but erroneously predicted changing dwell times in Experiment 2. Molar maximization theory did not accurately predict the results of either experim

ISSN:0022-5002    

DOI:10.1901/jeab.1992.58-445

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

The sensitivity of pigeons' schedule‐induced activity to operant consequences was studied in two experiments. During a 30‐s interval between food presentations, a keylight stimulus brightened incrementally. Stable terminal key pecking and interim locomotor activity developed. An operant “setback” contingency was applied to activity. The contingency arranged for locomotor movements (detected by a nine‐panel floorboard) to be followed by a resetting of the keylight brightness to a dimmer value and a 1‐s delay of reinforcement (for individual responses). Experiment 1 showed that activity patterns were highly sensitive to their operant consequences. Accompanying key‐peck rates were only transiently affected. In Experiment 2, the setback contingency was imposed during restricted portions of the trial, and differential operant control of activity was demonstrated. However, birds in this study produced higher rates of key pecking as activity rates were reduced. These results suggest that although schedule‐induced activity arises in response to the temporal arrangement of stimulus events, this behavior may retain considerable sensitivity to response‐cons

ISSN:0022-5002    

DOI:10.1901/jeab.1992.58-471

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Rats' presses on one lever canceled shocks programmed after variable cycles, while presses on a second lever occasionally produced a 2‐min timeout during which the shock‐deletion schedule was suspended and its correlated stimuli removed. These concurrent schedules of avoidance and timeout were embedded in a multiple schedule whose components differed, within and across conditions, in terms of the programmed shock rate associated with the shock‐deletion schedule. Analyses based on the generalized matching law suggest that the reduction in the response requirement correlated with termination of the avoidance schedule was a more important factor in the reinforcing effectiveness of timeout than was shock‐frequency reduction, at least in 2 of 3 rats. After training in each condition, responding on the timeout lever was extinguished by withholding timeouts in both components over seven sessions. Resistance to extinction varied directly with the rates of both shock‐frequency reduction and avoidance‐response reduction experienced during training. Although reduction in response effort appeared to dominate shock‐frequency reduction in the maintenance of responding, neither factor had a clear advantage in predicting the course

ISSN:0022-5002    

DOI:10.1901/jeab.1992.58-485

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Four pigeons responded in components of multiple schedules in which two responses were available and reinforced with food. Pecks on the left key (“main” key) were reinforced at a constant rate in one component and at a rate that varied over conditions in the other component. When reinforcer rate was varied, behavioral contrast occurred in the constant component. On the right key (“extra” key), five variable‐interval schedules and one variable‐ratio schedule, presented conjointly, arranged reinforcers for responses in all conditions. These conjoint schedules were common to both multiple‐schedule components—rather than unique to particular components—and reinforcers from these schedules could therefore be arranged in one component and obtained during the other component. In this way, the additional reinforcers were analogous to the “extraneous” reinforcers thought to maintain behavior other than pecking in conventional multiple schedules. Response rate on the extra key did not change systematically over conditions in the constant component, and in the varied component extra responding was inversely related to main‐key reinforcement. All subjects obtained more extra‐key reinforcers in whichever component arranged fewer main‐key reinforcers. Consistent with the theory that reallocation of extraneous reinforcers may cause behavioral contrast, absolute reinforcer rate for the extra key in the constant component was low in conditions that produced positive contrast on the main key and high in those that produced negative contrast. Also consistent with this theory, behavioral contrast was reduced in two conditions that canceled extra‐key reinforcers that had been arranged but not obtained at the end of components. Thus, a constraint on reallocation markedly r

ISSN:0022-5002    

DOI:10.1901/jeab.1992.58-497

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

ISSN:0022-5002    

DOI:10.1901/jeab.1992.58-512

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

In a discrete‐trials procedure with pigeons, a response on a green key led to a 4‐s delay (during which green houselights were lit) and then a reinforcer might or might not be delivered. A response on a red key led to a delay of adjustable duration (during which red houselights were lit) and then a certain reinforcer. The delay was adjusted so as to estimate an indifference point—a duration for which the two alternatives were equally preferred. Once the green key was chosen, a subject had to continue to respond on the green key until a reinforcer was delivered. Each response on the green key, plus the 4‐s delay that followed every response, was called one “link” of the green‐key schedule. Subjects showed much greater preference for the green key when the number of links before reinforcement was variable (averaging four) than when it was fixed (always exactly four). These findings are consistent with the view that probabilistic reinforcers are analogous to reinforcers delivered after variable delays. When successive links were separated by 4‐s or 8‐s “interlink intervals” with white houselights, preference for the probabilistic alternative decreased somewhat for 2 subjects but was unaffected for the other 2 subjects. When the interlink intervals had the same green houselights that were present during the 4‐s delays, preference for the green key decreased substantially for all subjects. These results provided mixed support for the view that preference for a probabilistic reinforcer is inversely related to the duration of conditioned reinforcers that prece

ISSN:0022-5002    

DOI:10.1901/jeab.1992.58-513

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Killeen and Fetterman's (1988) behavioral theory of animal timing predicts that decreases in the rate of reinforcement should produce decreases in the sensitivity (A′) of temporal discriminations and a decrease in miss and correct rejection rates (decrease in bias toward “long” responses). Eight rats were trained on a 10‐ versus 0.1‐s temporal discrimination with an intertrial interval of 5 s and were subsequently tested on probe days on the same discrimination with intertrial intervals of 1, 2.5, 5, 10, or 20 s. The rate of reinforcement declined for all animals as intertrial interval increased. Although sensitivity (A′) decreased with increasing intertrial interval, all rats showed an increase in bias to make lon

ISSN:0022-5002    

DOI:10.1901/jeab.1992.58-527

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY