摘要:

Pigeons responded on concurrent chains with equal initial‐ and terminal‐link durations. In all conditions, the terminal links of one chain ended reliably in reinforcement; the terminal links on the alternative chain ended in either food or blackout. In Experiment 1, the terminal‐link stimuli were correlated with (signaled) the outcome, and the durations of the initial and terminal links were varied across conditions. Preference did not vary systematically across conditions. In Experiment 2, terminal‐link durations were varied under different stimulus conditions. The initial links were variable‐interval 80‐s schedules. Preference for the reliable alternative was generally higher in unsignaled than in signaled conditions. Preference increased with terminal‐link durations only in the unsignaled conditions. There were no consistent differences between conditions with and without a common signal for reinforcement on the two chains. In the first series of conditions in Experiment 3, a single response was required in the initial links, and the stimulus conditions during 50‐s terminal links were varied. Preference for the reliable outcome approached 1.0 in unsignaled conditions and was considerably lower (below .50 for 3 of 5 subjects) in signaled conditions. In a final series of signaled conditions with relatively long terminal links, preference varied with duration of the initial links. The results extend previous findings and are discussed in terms of the delay reduction signaled by termin

ISSN:0022-5002    

DOI:10.1901/jeab.1990.53-201

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Pigeons' choice between reliable (100%) and unreliable (50%) reinforcement was studied using a concurrent‐chains procedure. Initial links were fixed‐ratio 1 schedules, and terminal links were equal fixed‐time schedules. The duration of the terminal links was varied across conditions. The terminal link on the reliable side always ended in food; the terminal link on the unreliable side ended with food 50% of the time and otherwise with blackout. Different stimuli present during the 50% terminal links signaled food or blackout outcomes under signaled conditions but were uncorrelated with outcomes under unsignaled conditions. In signaled conditions, most pigeons displayed a nearly exclusive preference for the 100% alternative when terminal links were short (5 or 10 s), but with terminal links of 30 s or longer, preference for the 100% alternative was sharply reduced (often to below .5). In unsignaled conditions, most pigeons showed extreme preference for the 100% alternative with either short (5 s) or longer (30 s) terminal links. Thus, pigeons' choice between reliable and unreliable reinforcement is influenced by both the signal conditions on the unreliable alternative and the duration of the terminal‐link delay. With a long delay and signaled outcomes, many pigeons display a suboptimal tendency to choose the unreliab

ISSN:0022-5002    

DOI:10.1901/jeab.1990.53-219

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

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 tende

ISSN:0022-5002    

DOI:10.1901/jeab.1990.53-235

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

In the first of four experiments, rats were exposed to a modified multiple continuous reinforcement‐extinction schedule during 15‐min daily sessions. In one condition (saves condition) with the cuelight on, a single lever press produced a food pellet, briefly extinguished the cuelight, and started a clock. Saves (additional lever presses with interresponse times less than 1 s) produced an additional food pellet, briefly extinguished the cuelight, and restarted the interresponse time clock. The cuelight was extinguished 1 s after the last lever press and remained off during a 10‐s period of extinction, during which no food pellets were delivered. In the other condition (savings account condition), the contingencies were the same except that the cuelight was extinguished and was not reilluminated after the initial lever press, and the delivery of all food pellets in the reinforcement component was delayed until the onset of extinction. In both conditions, rats made saves, but mean saves (total saves divided by the number of reinforcement components) were slightly reduced in the savings account condition. In Experiment 2, using six equally spaced 15‐min sessions per day on alternate days, saves were either followed immediately with food and brief cuelight offset (saves condition) or were not reinforced at all. Mean saves were much greater when saves were reinforced. In Experiment 3, during 5‐min daily sessions, saves earned a single pellet (savings account condition) or a number of pellets equal to the ordinal number of the lever press (interest condition). Rats made fewer mean saves, with little change in the food rate, when saves earned interest. In Experiment 4, the rats earned all their food in the operant situation during 24 daily 5‐min sessions, these separated by 55‐min intersession intervals during which no food was available; otherwise, the conditions were the same as in Experiment 3. In Experiment 4, the shift to interest for saves led to an increase in mean daily mean saves (total daily mean saves divided by the number of daily sessions) as well as to an increase in the number of food pellets delivered in each session. The results are discussed in terms of self‐control and behav

ISSN:0022-5002    

DOI:10.1901/jeab.1990.53-247

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

In Experiment 1, 4 rats earned their daily food ration by choosing between two levers. One lever delivered two regular and one quinine‐adulterated food pellets, and the other delivered two regular and four quinine pellets. A 20‐s intertrial interval separated successive choices. Sessions began with 10 forced trials during which only one lever, selected withp= .5 and cued by a light above it, could deliver its reinforcer. Forced trials were followed by 30 or 150 trials, depending on the condition, during which choices to either lever could be reinforced. Over this range, absolute choice of the four‐quinine, two‐regular‐pellet lever was inversely related to the number of free‐choice trials, establishing this reinforcer as an inferior good. In Condition 1 of Experiment 2, the prior design was altered in two ways: (a) one lever delivered four quinine pellets, and the other lever delivered one standard pellet; and (b) sessions ended after 140 free‐choice trials. When the number of free‐choice trials was reduced to 100 (Condition 2), all 3 rats increased their preference for quinine pellets, confirming their status as an inferior good. In the next several conditions, the number of quinine pellets provided for selecting its associated lever was varied between three and four. Preference for the quinine‐pellet alternative was inversely related to the number of pellets it provided, a result defining it as a Giffen good. These findings are not accommodated readily by extant choice models and complicate the search for a unitar

ISSN:0022-5002    

DOI:10.1901/jeab.1990.53-263

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Three experiments examined the effect of food availability on pigeons' choice behavior under concurrent schedules of reinforcement. In Experiment 1, 3 pigeons earned their daily food ration by choosing, in 30‐min sessions, between concurrent variable‐ratio 30 variable‐interval 40‐s schedules. Food presentations during both schedules lasted 2 or 12 s, depending upon the condition. Relative variable‐ratio response rate was inversely related to hopper duration. In Experiment 2, 4 pigeons received their daily feeding by responding on the same schedule pair as in Experiment 1 (with 4‐s food presentations) in sessions that varied in length from 10 to 30 min, depending on the condition. The length of a vertical slit projected on a response key increased with time so that “passage of time” might be more easily discriminable. As session duration decreased, relative variable‐ratio response rate increased. In Experiment 3, 4 pigeons chose between two variable‐interval 40‐s schedules. One schedule operated without regard to the schedule selected, whereas the other operated only when the subject responded in its presence (dependent). Although these schedules had the same feedback function, preference for the dependent variable interval increased as session duration decreased from 30 to 10 min. The preference changes in these studies reveal the operation of an income‐maxim

ISSN:0022-5002    

DOI:10.1901/jeab.1990.53-273

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Key presses of 1 monkey (called the performer) became the basis upon which a 2nd monkey (called the judge) solved conditional‐discrimination tasks. First, the performer was trained to press one of two colored choice keys (red or green) depending on the location of a white light in her chamber. The performer's key‐pressing behavior was brought under the control of the experimenter by this procedure. Subsequently, the judge was trained to discriminate the performer's key‐pressing behavior. In Experiment 1, the judge had to press Key 1 when the performer pressed the red choice key and Key 2 when the performer pressed the green choice key. In Experiment 2, a sample key was introduced. The judge had to press Key 1 when the performer pressed the same colored choice key as the sample; the judge had to press Key 2 when the performer pressed the different colored choice key. In both experiments, the judge was required to attend to the behavior of the performer. It was shown that the performer's behavior served as a discriminative stimulus for the judge's responses in a conditional‐discriminati

ISSN:0022-5002    

DOI:10.1901/jeab.1990.53-285

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

During 50‐min sessions, 6 male human subjects could press either Button A or Button B available as nonreversible options. Button A presses were nonaggressive responses and earned points according to a fixed‐ratio 100 schedule. Prior to the experiment subjects were instructed that every 10 (fixed‐ratio 10) Button B presses (aggressive responses) subtracted a point from a fictitious 2nd subject. A random‐time schedule of point loss was used to engender aggressive responding. The instructions attributed these point losses to the Button B presses of the subject's fictitious partner. Aggressive responding either escaped or avoided point loss by initiating an interval free of point loss. The duration of the interval was varied systematically across sessions. Avoidance contingencies maintained a high rate of aggressive responding over 30 sessions in the absence of point loss. Escape contingencies also maintained aggressive responding across sessions, with rates of aggressive responding corresponding to rates of poi

ISSN:0022-5002    

DOI:10.1901/jeab.1990.53-293

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

ISSN:0022-5002    

DOI:10.1901/jeab.1990.53-305

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY