Thomas Zentall - Profile on Academia.edu (original) (raw)

Papers by Thomas Zentall

Research paper thumbnail of Self-regulatory depletion in dogs: insulin release is not necessary for the replenishment of persistence

Behavioural processes, 2015

It has been hypothesized that self-control is constrained by a limited energy resource that can b... more It has been hypothesized that self-control is constrained by a limited energy resource that can be depleted through exertion. Once depleted, this resource can be replenished by the consumption or even the taste of glucose. For example, the need to inhibit reduces subsequent persistence at problem solving by humans and dogs, an effect that is not observed when a glucose drink (but not a placebo) is administered following initial inhibition. The mechanism for replenishment by glucose is currently unknown. Energy transfer is not necessary, although insulin secretion may be involved. This possibility was investigated in the current study by having dogs exert self-control (sit-stay) and subsequently giving them (1) glucose that causes the release of insulin, (2) fructose that does not result in the release of insulin nor does it affect glucose levels (but it is a carbohydrate), or (3) a calorie-free drink. Persistence measures indicated that both glucose and fructose replenished canine p...

Research paper thumbnail of Object permanence in dogs: Invisible displacement in a rotation task

Psychonomic Bulletin & Review, 2009

Research paper thumbnail of Repeated cocaine experience facilitates sucrose-reinforced operant responding in enriched and isolated rats

Learning and Motivation, 2007

The purpose of the present experiment was to determine whether repeated cocaine exposure differen... more The purpose of the present experiment was to determine whether repeated cocaine exposure differentially affects sucrose-reinforced operant responding in rats raised in an enriched condition (EC) or an isolated condition (IC). Specifically, the performance of EC and IC rats pressing a lever for sucrose under a high fixed-ratio schedule (FR 30) prior to and after 10 days of exposure to cocaine (15 mg/kg, i.p.) or saline was compared. Regardless of rearing condition, rats repeatedly exposed to cocaine had shorter reacquisition latencies to complete a sucrose-reinforced FR 30 task than saline controls. The results suggest that cocaine exposure may have crosssensitized both EC and IC rats to the reinforcing effects of sucrose or sucrose-associated cues, thus facilitating reacquisition of operant responding.

Research paper thumbnail of Six-term transitive inference with pigeons: Successive-pair training followed by mixed-pair training

Journal of the Experimental Analysis of Behavior, 2013

In nonhuman animals, the transitive inference (TI) task typically involves training a series of f... more In nonhuman animals, the transitive inference (TI) task typically involves training a series of four simultaneous discriminations involving, for example, arbitrary colors in which choice of one stimulus in each pair is reinforced [+] and choice of the other color is nonreinforced [-]. This can be represented as A+B-, B+C-, C+D-, D+E-and can be conceptualized as a series of linear relationships: A>B>C>D>E. After training, animals are tested on the untrained non endpoint pair, BD. Preference for B over D is taken as evidence of TI and occurs because B is greater than D in the implied series. In the present study we trained pigeons using a novel training procedure-a hybrid of successive pair training (training one pair at a time) and mixed pair training (training all pairs at once)-designed to overcome some of the limitations of earlier procedures. Using this hybrid procedure, we trained five premise pairs (A+B-, B+C-, C+D-, D+E-, and E+F-) which allowed us to test three untrained non endpoint pairs (BD, CE, and BE). A significant TI effect was found for most subjects on at least two out of three test pairs. Different theories of TI are discussed. The results suggest that this hybrid training is an efficient procedure for establishing mixed pair acquisition and a TI effect. transitive inference; value transfer; simultaneous discriminations; pigeons Piaget ( , 1955) ) described a transitive inference (TI) task in which a child might be

Research paper thumbnail of Pigeons prefer discriminative stimuli independently of the overall probability of reinforcement and of the number of presentations of the conditioned reinforcer

Journal of Experimental Psychology: Animal Behavior Processes, 2012

Research paper thumbnail of Imitation and Affordance Learning by Pigeons (Columba livia)

Journal of Comparative Psychology, 2003

The bidirectional control procedure was used to determine whether pigeons (Columba livia) would i... more The bidirectional control procedure was used to determine whether pigeons (Columba livia) would imitate a demonstrator that pushed a sliding screen for food. One group of observers saw a trained demonstrator push a sliding screen door with its beak (imitation group), whereas 2 other groups watched the screen move independently (possibly learning how the environment works) with a conspecific either present (affordance learning with social facilitation) or absent (affordance learning alone). A 4th group could not see the screen being pushed (sound and odor control). Imitation was evidenced by the finding that pigeons that saw a demonstrator push the screen made a higher proportion of matching screen pushes than observers in 2 appropriate control conditions. Further, observers that watched a screen move without a demonstrator present made a significantly higher proportion of matching screen pushes than would be expected by chance. Thus, these pigeons were capable of affordance learning.

Research paper thumbnail of Social facilitation of d-amphetamine self-administration in rats

Experimental and Clinical Psychopharmacology, 2011

The link between social influence and drug abuse has long been established in humans. However, pr... more The link between social influence and drug abuse has long been established in humans. However, preclinical animal models of drug abuse have only recently begun to consider the role of social influence. Since social factors influence the initiation and maintenance of drug use in humans, it is important to include these factors in preclinical animal models. The current study examined the effects of the presence of a social partner on responding for sucrose pellets under various motivational conditions, as well as on d-amphetamine (AMPH) self-administration. Rats were trained to lever press for either sucrose pellets or AMPH (0.01 or 0.1 mg/kg/infusion unit dose). Following response stability, a novel same-sex conspecific was presented in an adjacent compartment separated by a clear Plexiglas wall, and responding for sucrose or AMPH reward was measured. Rats were allowed to restabilize, and were subsequently given an additional partner presentation. Presence of the social partner increased responding only during the first partner pairing in the AMPH 0.1 mg/kg/infusion unit dose, whereas inhibition of responding was observed during the first partner pairing during access to the 0.01 mg/kg/infusion unit dose. Under free feed conditions, inhibition of sucrose pellet responding was observed in the presence of the social partner, but this effect was attenuated under food restriction. In contrast, the results demonstrate social facilitation of AMPH self-administration at a high unit dose, thus extending the influence of social factors to an operant conditioning task. This model of social facilitation may have important implications as a preclinical model of social influence on drug abuse.

Research paper thumbnail of The case of the disappearing bone: Dogs’ understanding of the physical properties of objects

The case of the disappearing bone: Dogs’ understanding of the physical properties of objects

Behavioural Processes, 2010

To assess dogs&am... more To assess dogs' memory for an occluded object, a gaze duration procedure was used similar to one often used with nonverbal infants. A bone shaped dog biscuit was placed behind a solid screen that then rotated in the depth plane through an arc front to back. Dogs were shown either of the two test events. In one event (the possible event), the screen rotated until it reached the point at which it would have reached the bone and then stopped (about 120°); in the other event (the impossible event), the screen rotated through a full 180° arc, as though it had passed through the bone. The dogs looked significantly longer at the impossible event. To control for the differential time it took for the screen to move, for a control group, a bone was placed behind the screen and the screen was rotated either 60° or 120° (both possible events). No difference in looking time was found. To control for the movement of the screen through 120° or 180° when both were possible, for a second control group, the bone was placed to the side of the screen rather than behind the screen and the screen was moved 120° or 180°. Again, no significant difference in looking time was found. Results suggest that much like young children, dogs understand the physical properties of an occluded object. That is they appear to understand that an object (such as a screen) should not be able to pass through another object (such as dog bone).

Research paper thumbnail of Nature’s Turing Test

Proceedings of the Twenty-Fourth Annual Conference of the Cognitive Science Society, 2019

Research paper thumbnail of True Imitative Learning in Pigeons

Psychological Science, 1996

Providing evidence for imitative learning in animals has been made difficult by the need to contr... more Providing evidence for imitative learning in animals has been made difficult by the need to control for a number of possible nonimitation accounts (e.g., mere presence of another animal, attention drawn to a location, attention drawn to an object being manipulated) that often have not been recognized in previous research In the present experiment we used a version of the two-action method in which a treadle could be operated by a pigeon in one of two distinctive ways with its beak by pecking or with its foot by stepping What is unique in this experiment is not only the distinct response topographies, but also that both responses have the same effect on the environment (depression of the treadle followed by food reward) When pigeons that had observed one of the two response topographies were given access to the treadle, a significant correspondence was found between the topography of the observers responses and that of their respective demonstrators' responses

Research paper thumbnail of Simultaneous discrimination learning in pigeons: value of S- affects the relative value of its associated S+

Simultaneous discrimination learning in pigeons: value of S- affects the relative value of its associated S+

The Quarterly journal of experimental psychology. B, Comparative and physiological psychology, 1998

In a simple simultaneous discrimination involving a positive stimulus (S+) and a negative stimulu... more In a simple simultaneous discrimination involving a positive stimulus (S+) and a negative stimulus (S-), it has been hypothesized that positive value can transfer from the S+ to the S- (thus increasing the relative value of the S-) and also that negative value can transfer from the S- to the S+ (thus diminishing the relative value of the S+; Fersen, Wynne, Delius, & Staddon, 1991). Evidence for positive value transfer has been reported in pigeons (e.g. Zentall & Sherburne, 1994). The purpose of the present experiments was to determine, in a simultaneous discrimination, whether the S- diminishes the value of the S+ or the S- is contrasted with the S+ (thus enhancing the value of the S+). In two experiments, we found evidence for contrast, rather than value transfer, attributable to simultaneous discrimination training. Thus, not only does the S+ appear to enhance the value of the S-, but the S- appears to enhance rather than reduce the value of the S+.

Research paper thumbnail of Asymmetrical Coding of Food and No-Food Events by Pigeons: Sample Pecking versus Food as the Basis of the Sample Code

Learning and Motivation, 1993

Research paper thumbnail of Role of differential sample responding in the differential outcomes effect involving delayed matching by pigeons

Journal of Experimental Psychology: Animal Behavior Processes, 1994

Research paper thumbnail of Delayed matching in pigeons: can apparent memory loss be attributed to the delay of reinforcement of sample-orienting behavior?

Behavioural Processes, 1998

In earlier research using constant-delay matching with pigeons, there is evidence that delay of r... more In earlier research using constant-delay matching with pigeons, there is evidence that delay of reinforcement of sample-orienting behavior may contribute to the decline in matching accuracy with increasing delay between sample and comparison stimuli. In the present research using this procedure, we found that a significant decline in matching accuracy between the first and second session can occur when delays are relatively long. This effect cannot be accounted for in terms of either additional memory loss or surprise (generalization decrement) associated with the increase in delay. Furthermore, the decline in matching accuracy occurred regardless of whether the delay was inserted between samples and comparisons (where it would be expected to affect the use of sample memory in making the comparison choice response) or between comparisons and reinforcement (where it would not be expected to affect the use of sample memory in making the comparison choice response). Thus, the decrease in matching accuracy between Session 1 and 2 following an increase in delay appears to be unrelated to sample memory at the time of choice. Instead, the results suggest that delay of reinforcement of sample-orienting behavior may play an important role in the negative slope of the retention functions obtained when constant-or mixed-delay matching procedures are used to assess animal memory.

Research paper thumbnail of Contrast and the justification of effort

Psychonomic Bulletin & Review, 2005

Research paper thumbnail of Serial Pattern Learning: Pigeons Prefer an Improving Schedule Over an Initially Easier Fixed Ratio Schedule

Serial pattern learning describes behavior in which a subject anticipates not only the time and e... more Serial pattern learning describes behavior in which a subject anticipates not only the time and effort needed for the next reinforcer but also the pattern of time and effort to reinforcers after the first. Chandel et al. (2021) found that pigeons left a progressive schedule (in which each reinforcer was successively harder to obtain) earlier than would have been optimal. They argued that the pigeons anticipated the harder to obtain reinforcers beyond the next one. In the present experiments, pigeons were trained on a progressive schedule for which each reinforcer was successively easier to obtain but the initial choice was between a fixed ratio schedule (FR23) for which a reinforcer was easier to obtain than the first reinforcer on the improving progressive schedule (32 pecks). Delayed discounting suggests that the pigeons would prefer the FR23 because more immediate reinforcers should be preferred, whereas serial pattern learning suggests that the progressive schedule might be pref...

Research paper thumbnail of Can Imitation in Pigeons be Explained by Local Enhancement Together with Trial-and-Error Learning?

Psychological Science, 1997

Zentall Sutton and Sherburne (1996) reported that pigeons observing a conspecific demonstrator ei... more Zentall Sutton and Sherburne (1996) reported that pigeons observing a conspecific demonstrator either step on or peck at a treadle to obtain food subsequently showed a significant tendency to manipulate the treadle as had their demonstrator Zentall et al suggested this finding showed observer pigeons had learned by imitation to peck at or step on the treadle However, the same result might have been obtained if pigeons had learned to step on the treadle by trial and error, and pigeons exposed to a treadle-pecking demonstrator had come to peck at the treadle as a result of nonimitative social-learning processes such as local enhancement or contagion Here we report the results for two control groups showing that pigeons do not learn to step on or peck at a treadle for food reward unless they observe a relevant demonstrator These results considerably strengthen the original conclusion Future research using the two action method to demonstrate imitative learning should include similar co...

Research paper thumbnail of Interval timing with gaps: Gap ambiguity as an alternative to temporal decay

Journal of Experimental Psychology: Animal Behavior Processes, 2005

(2005) proposed a hypothesis of timing in rats to account for the results of experiments that hav... more (2005) proposed a hypothesis of timing in rats to account for the results of experiments that have used the peak procedure with gaps. According to this hypothesis, the introduction of a gap causes the animal's memory for the pregap interval to passively decay (subjectively shorten) in direct proportion to the duration and salience of the gap. Thus, animals should pause with short, nonsalient gaps but should reset their clock with longer, salient gaps. The present authors suggest that the ambiguity of the gap (i.e., the similarity between the gap and the intertrial interval in both appearance and relative duration) causes the animal to actively reset the clock and prevents adequate assessments of the fate of timed intervals prior to the gap. Furthermore, when the intertrial interval is discriminable from the gap, the evidence suggests that timed intervals prior to the gap are not lost but are retained in memory.

Research paper thumbnail of Social learning in humans and nonhuman animals: Theoretical and empirical dissections

Journal of Comparative Psychology, 2012

Research paper thumbnail of BRIEF COMMUNICATION Memory Mechanisms in Pigeons: Evidence of Base-Rate Neglect

In delayed matching to sample, once acquired, pigeons presumably choose comparisons according to ... more In delayed matching to sample, once acquired, pigeons presumably choose comparisons according to their memory for (the strength of) the sample. When memory for the sample is sufficiently weak, comparison choice should depend on the history of reinforcement associated with each of the comparison stimuli. In the present research, pigeons acquired two matching tasks in which Sample S1 was associated with one comparison from each task, C1 and C3, whereas Sample S2 was associated with Comparison C2, and Sample S3 was associated with Comparison C4. As the retention interval increased, the pigeons showed a bias to choose the comparison (C1 or C3) associated with the more frequently occurring sample (S1). Thus, pigeons were sensitive also to the (irrelevant) likelihood that each of the samples was presented. The results suggest that pigeons may allow their reference memory for the overall sample frequency to influence comparison choice, independent of the comparison stimuli present.

Research paper thumbnail of Self-regulatory depletion in dogs: insulin release is not necessary for the replenishment of persistence

Behavioural processes, 2015

It has been hypothesized that self-control is constrained by a limited energy resource that can b... more It has been hypothesized that self-control is constrained by a limited energy resource that can be depleted through exertion. Once depleted, this resource can be replenished by the consumption or even the taste of glucose. For example, the need to inhibit reduces subsequent persistence at problem solving by humans and dogs, an effect that is not observed when a glucose drink (but not a placebo) is administered following initial inhibition. The mechanism for replenishment by glucose is currently unknown. Energy transfer is not necessary, although insulin secretion may be involved. This possibility was investigated in the current study by having dogs exert self-control (sit-stay) and subsequently giving them (1) glucose that causes the release of insulin, (2) fructose that does not result in the release of insulin nor does it affect glucose levels (but it is a carbohydrate), or (3) a calorie-free drink. Persistence measures indicated that both glucose and fructose replenished canine p...

Research paper thumbnail of Object permanence in dogs: Invisible displacement in a rotation task

Psychonomic Bulletin & Review, 2009

Research paper thumbnail of Repeated cocaine experience facilitates sucrose-reinforced operant responding in enriched and isolated rats

Learning and Motivation, 2007

The purpose of the present experiment was to determine whether repeated cocaine exposure differen... more The purpose of the present experiment was to determine whether repeated cocaine exposure differentially affects sucrose-reinforced operant responding in rats raised in an enriched condition (EC) or an isolated condition (IC). Specifically, the performance of EC and IC rats pressing a lever for sucrose under a high fixed-ratio schedule (FR 30) prior to and after 10 days of exposure to cocaine (15 mg/kg, i.p.) or saline was compared. Regardless of rearing condition, rats repeatedly exposed to cocaine had shorter reacquisition latencies to complete a sucrose-reinforced FR 30 task than saline controls. The results suggest that cocaine exposure may have crosssensitized both EC and IC rats to the reinforcing effects of sucrose or sucrose-associated cues, thus facilitating reacquisition of operant responding.

Research paper thumbnail of Six-term transitive inference with pigeons: Successive-pair training followed by mixed-pair training

Journal of the Experimental Analysis of Behavior, 2013

In nonhuman animals, the transitive inference (TI) task typically involves training a series of f... more In nonhuman animals, the transitive inference (TI) task typically involves training a series of four simultaneous discriminations involving, for example, arbitrary colors in which choice of one stimulus in each pair is reinforced [+] and choice of the other color is nonreinforced [-]. This can be represented as A+B-, B+C-, C+D-, D+E-and can be conceptualized as a series of linear relationships: A>B>C>D>E. After training, animals are tested on the untrained non endpoint pair, BD. Preference for B over D is taken as evidence of TI and occurs because B is greater than D in the implied series. In the present study we trained pigeons using a novel training procedure-a hybrid of successive pair training (training one pair at a time) and mixed pair training (training all pairs at once)-designed to overcome some of the limitations of earlier procedures. Using this hybrid procedure, we trained five premise pairs (A+B-, B+C-, C+D-, D+E-, and E+F-) which allowed us to test three untrained non endpoint pairs (BD, CE, and BE). A significant TI effect was found for most subjects on at least two out of three test pairs. Different theories of TI are discussed. The results suggest that this hybrid training is an efficient procedure for establishing mixed pair acquisition and a TI effect. transitive inference; value transfer; simultaneous discriminations; pigeons Piaget ( , 1955) ) described a transitive inference (TI) task in which a child might be

Research paper thumbnail of Pigeons prefer discriminative stimuli independently of the overall probability of reinforcement and of the number of presentations of the conditioned reinforcer

Journal of Experimental Psychology: Animal Behavior Processes, 2012

Research paper thumbnail of Imitation and Affordance Learning by Pigeons (Columba livia)

Journal of Comparative Psychology, 2003

The bidirectional control procedure was used to determine whether pigeons (Columba livia) would i... more The bidirectional control procedure was used to determine whether pigeons (Columba livia) would imitate a demonstrator that pushed a sliding screen for food. One group of observers saw a trained demonstrator push a sliding screen door with its beak (imitation group), whereas 2 other groups watched the screen move independently (possibly learning how the environment works) with a conspecific either present (affordance learning with social facilitation) or absent (affordance learning alone). A 4th group could not see the screen being pushed (sound and odor control). Imitation was evidenced by the finding that pigeons that saw a demonstrator push the screen made a higher proportion of matching screen pushes than observers in 2 appropriate control conditions. Further, observers that watched a screen move without a demonstrator present made a significantly higher proportion of matching screen pushes than would be expected by chance. Thus, these pigeons were capable of affordance learning.

Research paper thumbnail of Social facilitation of d-amphetamine self-administration in rats

Experimental and Clinical Psychopharmacology, 2011

The link between social influence and drug abuse has long been established in humans. However, pr... more The link between social influence and drug abuse has long been established in humans. However, preclinical animal models of drug abuse have only recently begun to consider the role of social influence. Since social factors influence the initiation and maintenance of drug use in humans, it is important to include these factors in preclinical animal models. The current study examined the effects of the presence of a social partner on responding for sucrose pellets under various motivational conditions, as well as on d-amphetamine (AMPH) self-administration. Rats were trained to lever press for either sucrose pellets or AMPH (0.01 or 0.1 mg/kg/infusion unit dose). Following response stability, a novel same-sex conspecific was presented in an adjacent compartment separated by a clear Plexiglas wall, and responding for sucrose or AMPH reward was measured. Rats were allowed to restabilize, and were subsequently given an additional partner presentation. Presence of the social partner increased responding only during the first partner pairing in the AMPH 0.1 mg/kg/infusion unit dose, whereas inhibition of responding was observed during the first partner pairing during access to the 0.01 mg/kg/infusion unit dose. Under free feed conditions, inhibition of sucrose pellet responding was observed in the presence of the social partner, but this effect was attenuated under food restriction. In contrast, the results demonstrate social facilitation of AMPH self-administration at a high unit dose, thus extending the influence of social factors to an operant conditioning task. This model of social facilitation may have important implications as a preclinical model of social influence on drug abuse.

Research paper thumbnail of The case of the disappearing bone: Dogs’ understanding of the physical properties of objects

The case of the disappearing bone: Dogs’ understanding of the physical properties of objects

Behavioural Processes, 2010

To assess dogs&am... more To assess dogs' memory for an occluded object, a gaze duration procedure was used similar to one often used with nonverbal infants. A bone shaped dog biscuit was placed behind a solid screen that then rotated in the depth plane through an arc front to back. Dogs were shown either of the two test events. In one event (the possible event), the screen rotated until it reached the point at which it would have reached the bone and then stopped (about 120°); in the other event (the impossible event), the screen rotated through a full 180° arc, as though it had passed through the bone. The dogs looked significantly longer at the impossible event. To control for the differential time it took for the screen to move, for a control group, a bone was placed behind the screen and the screen was rotated either 60° or 120° (both possible events). No difference in looking time was found. To control for the movement of the screen through 120° or 180° when both were possible, for a second control group, the bone was placed to the side of the screen rather than behind the screen and the screen was moved 120° or 180°. Again, no significant difference in looking time was found. Results suggest that much like young children, dogs understand the physical properties of an occluded object. That is they appear to understand that an object (such as a screen) should not be able to pass through another object (such as dog bone).

Research paper thumbnail of Nature’s Turing Test

Proceedings of the Twenty-Fourth Annual Conference of the Cognitive Science Society, 2019

Research paper thumbnail of True Imitative Learning in Pigeons

Psychological Science, 1996

Providing evidence for imitative learning in animals has been made difficult by the need to contr... more Providing evidence for imitative learning in animals has been made difficult by the need to control for a number of possible nonimitation accounts (e.g., mere presence of another animal, attention drawn to a location, attention drawn to an object being manipulated) that often have not been recognized in previous research In the present experiment we used a version of the two-action method in which a treadle could be operated by a pigeon in one of two distinctive ways with its beak by pecking or with its foot by stepping What is unique in this experiment is not only the distinct response topographies, but also that both responses have the same effect on the environment (depression of the treadle followed by food reward) When pigeons that had observed one of the two response topographies were given access to the treadle, a significant correspondence was found between the topography of the observers responses and that of their respective demonstrators' responses

Research paper thumbnail of Simultaneous discrimination learning in pigeons: value of S- affects the relative value of its associated S+

Simultaneous discrimination learning in pigeons: value of S- affects the relative value of its associated S+

The Quarterly journal of experimental psychology. B, Comparative and physiological psychology, 1998

In a simple simultaneous discrimination involving a positive stimulus (S+) and a negative stimulu... more In a simple simultaneous discrimination involving a positive stimulus (S+) and a negative stimulus (S-), it has been hypothesized that positive value can transfer from the S+ to the S- (thus increasing the relative value of the S-) and also that negative value can transfer from the S- to the S+ (thus diminishing the relative value of the S+; Fersen, Wynne, Delius, & Staddon, 1991). Evidence for positive value transfer has been reported in pigeons (e.g. Zentall & Sherburne, 1994). The purpose of the present experiments was to determine, in a simultaneous discrimination, whether the S- diminishes the value of the S+ or the S- is contrasted with the S+ (thus enhancing the value of the S+). In two experiments, we found evidence for contrast, rather than value transfer, attributable to simultaneous discrimination training. Thus, not only does the S+ appear to enhance the value of the S-, but the S- appears to enhance rather than reduce the value of the S+.

Research paper thumbnail of Asymmetrical Coding of Food and No-Food Events by Pigeons: Sample Pecking versus Food as the Basis of the Sample Code

Learning and Motivation, 1993

Research paper thumbnail of Role of differential sample responding in the differential outcomes effect involving delayed matching by pigeons

Journal of Experimental Psychology: Animal Behavior Processes, 1994

Research paper thumbnail of Delayed matching in pigeons: can apparent memory loss be attributed to the delay of reinforcement of sample-orienting behavior?

Behavioural Processes, 1998

In earlier research using constant-delay matching with pigeons, there is evidence that delay of r... more In earlier research using constant-delay matching with pigeons, there is evidence that delay of reinforcement of sample-orienting behavior may contribute to the decline in matching accuracy with increasing delay between sample and comparison stimuli. In the present research using this procedure, we found that a significant decline in matching accuracy between the first and second session can occur when delays are relatively long. This effect cannot be accounted for in terms of either additional memory loss or surprise (generalization decrement) associated with the increase in delay. Furthermore, the decline in matching accuracy occurred regardless of whether the delay was inserted between samples and comparisons (where it would be expected to affect the use of sample memory in making the comparison choice response) or between comparisons and reinforcement (where it would not be expected to affect the use of sample memory in making the comparison choice response). Thus, the decrease in matching accuracy between Session 1 and 2 following an increase in delay appears to be unrelated to sample memory at the time of choice. Instead, the results suggest that delay of reinforcement of sample-orienting behavior may play an important role in the negative slope of the retention functions obtained when constant-or mixed-delay matching procedures are used to assess animal memory.

Research paper thumbnail of Contrast and the justification of effort

Psychonomic Bulletin & Review, 2005

Research paper thumbnail of Serial Pattern Learning: Pigeons Prefer an Improving Schedule Over an Initially Easier Fixed Ratio Schedule

Serial pattern learning describes behavior in which a subject anticipates not only the time and e... more Serial pattern learning describes behavior in which a subject anticipates not only the time and effort needed for the next reinforcer but also the pattern of time and effort to reinforcers after the first. Chandel et al. (2021) found that pigeons left a progressive schedule (in which each reinforcer was successively harder to obtain) earlier than would have been optimal. They argued that the pigeons anticipated the harder to obtain reinforcers beyond the next one. In the present experiments, pigeons were trained on a progressive schedule for which each reinforcer was successively easier to obtain but the initial choice was between a fixed ratio schedule (FR23) for which a reinforcer was easier to obtain than the first reinforcer on the improving progressive schedule (32 pecks). Delayed discounting suggests that the pigeons would prefer the FR23 because more immediate reinforcers should be preferred, whereas serial pattern learning suggests that the progressive schedule might be pref...

Research paper thumbnail of Can Imitation in Pigeons be Explained by Local Enhancement Together with Trial-and-Error Learning?

Psychological Science, 1997

Zentall Sutton and Sherburne (1996) reported that pigeons observing a conspecific demonstrator ei... more Zentall Sutton and Sherburne (1996) reported that pigeons observing a conspecific demonstrator either step on or peck at a treadle to obtain food subsequently showed a significant tendency to manipulate the treadle as had their demonstrator Zentall et al suggested this finding showed observer pigeons had learned by imitation to peck at or step on the treadle However, the same result might have been obtained if pigeons had learned to step on the treadle by trial and error, and pigeons exposed to a treadle-pecking demonstrator had come to peck at the treadle as a result of nonimitative social-learning processes such as local enhancement or contagion Here we report the results for two control groups showing that pigeons do not learn to step on or peck at a treadle for food reward unless they observe a relevant demonstrator These results considerably strengthen the original conclusion Future research using the two action method to demonstrate imitative learning should include similar co...

Research paper thumbnail of Interval timing with gaps: Gap ambiguity as an alternative to temporal decay

Journal of Experimental Psychology: Animal Behavior Processes, 2005

(2005) proposed a hypothesis of timing in rats to account for the results of experiments that hav... more (2005) proposed a hypothesis of timing in rats to account for the results of experiments that have used the peak procedure with gaps. According to this hypothesis, the introduction of a gap causes the animal's memory for the pregap interval to passively decay (subjectively shorten) in direct proportion to the duration and salience of the gap. Thus, animals should pause with short, nonsalient gaps but should reset their clock with longer, salient gaps. The present authors suggest that the ambiguity of the gap (i.e., the similarity between the gap and the intertrial interval in both appearance and relative duration) causes the animal to actively reset the clock and prevents adequate assessments of the fate of timed intervals prior to the gap. Furthermore, when the intertrial interval is discriminable from the gap, the evidence suggests that timed intervals prior to the gap are not lost but are retained in memory.

Research paper thumbnail of Social learning in humans and nonhuman animals: Theoretical and empirical dissections

Journal of Comparative Psychology, 2012

Research paper thumbnail of BRIEF COMMUNICATION Memory Mechanisms in Pigeons: Evidence of Base-Rate Neglect

In delayed matching to sample, once acquired, pigeons presumably choose comparisons according to ... more In delayed matching to sample, once acquired, pigeons presumably choose comparisons according to their memory for (the strength of) the sample. When memory for the sample is sufficiently weak, comparison choice should depend on the history of reinforcement associated with each of the comparison stimuli. In the present research, pigeons acquired two matching tasks in which Sample S1 was associated with one comparison from each task, C1 and C3, whereas Sample S2 was associated with Comparison C2, and Sample S3 was associated with Comparison C4. As the retention interval increased, the pigeons showed a bias to choose the comparison (C1 or C3) associated with the more frequently occurring sample (S1). Thus, pigeons were sensitive also to the (irrelevant) likelihood that each of the samples was presented. The results suggest that pigeons may allow their reference memory for the overall sample frequency to influence comparison choice, independent of the comparison stimuli present.