Peter Judge - Academia.edu (original) (raw)

Conference Presentations by Peter Judge

Tool-use requires the manipulation of an object in the environment to achieve a goal, and the abi... more Tool-use requires the manipulation of an object in the environment to achieve a goal, and the ability to relate one object to another. We used a two-choice tool task to test for comprehension of tool use in three lion-tailed macaques. First, we investigated their comprehension of tool-object relations by presenting a choice between two hook-shaped tools, one of which was baited with a food reward inside the hook (the correct choice) and the other had the reward outside the hook. Two of the three subjects reached criterion (10 out of 12 correct, in 2 consecutive sessions) in 20 sessions, and the third reached criterion in 40 sessions. The second experiment introduced parabola-shaped tools to test whether the subjects could generalize to new tools. All subjects reached criterion in 12 sessions. The third experiment introduced barriers to determine if animals understood the relation between a tool, an object (the reward) and another object in the environment. Subjects needed to choose the tool that was not impeded by a barrier. Two of the three subjects reached criterion in 50 sessions, and the third did not reach criterion in 50 sessions. Results indicated that lion-tailed macaques understood the causal relations between tools and the objects on which they were acting. The design provided a standardized means to compare tool use comprehension across many primate species.

Papers by Peter Judge

This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/authorsrights

International Journal of Comparative Psychology, 2013

Author(s): Judge, Peter G.; Essler, Jennifer L. | Abstract: Self-control is a prerequisite for co... more Author(s): Judge, Peter G.; Essler, Jennifer L. | Abstract: Self-control is a prerequisite for complex cognitive processes such as cooperation and planning. As such, comparative studies of self-control may help elucidate the evolutionary origin of these capacities. A variety of methods have been developed to test for self-control in non-human primates that include some variation of foregoing an immediate reward in order to gain a more favorable reward. We used a token exchange paradigm to test for self-control in capuchin monkeys (Cebus apella). Animals were trained that particular tokens could be exchanged for food items worth different values. To test for self-control, a monkey was provided with a token that was associated with a lower-value food. When the monkey exchanged the token, the experimenter provided the monkey with a choice between the lower-value food item associated with the token or another token that was associated with a higher-value food. If the monkey chose the to...

American Journal of Primatology, 1993

... than their male age peers [Bercovitch, 1983; Clark, 1978; Eaton et al., 1981; Hor-rocks &... more ... than their male age peers [Bercovitch, 1983; Clark, 1978; Eaton et al., 1981; Hor-rocks & Hunte, 1983; Loy et al ... Bernstein and Ehardt [ 19861 suggested few differences in agonistic behavior among juvenile rhesus monkeys, and that adult males selectively interfere in agonistic ...

International Journal of Comparative Psychology, 2013

American Journal of Primatology, 1991

Journal of Comparative Psychology, 2015

Previous research has suggested that several primate species may be capable of reasoning by exclu... more Previous research has suggested that several primate species may be capable of reasoning by exclusion based on the finding that they can locate a hidden object when given information about where the object is not. The present research replicated and extended the literature by testing 2 Old World monkey species, lion-tailed macaques (Macaca silenus) and a hamadryas baboon (Papio hamadryas), and 2 New World species, capuchin monkeys (Sapajus apella) and squirrel monkeys (Saimiri sciureus). The New World monkeys were tested on the traditional 2-way object choice task, and all 4 species were also tested on a more complex 3-way object choice task. In addition, the squirrel monkeys were tested on a 2-way object choice task with auditory information. The results showed that, whereas the Old World species were able to infer by exclusion on the 3-object task, some of the capuchin monkeys had difficulty on each of the 2- and 3-cup tasks. All but 1 of the squirrel monkeys failed to infer successfully, and their strategies appeared to differ between the visual and auditory versions of the task. Taken together, this research suggests that the ability to succeed on this inference task may be present throughout Old World monkey species, but is fragile in the New World species tested thus far. (PsycINFO Database Record

Journal of Comparative Psychology, 2015

Motor planning is a relatively complex cognitive skill in which an actor modifies a behavior to a... more Motor planning is a relatively complex cognitive skill in which an actor modifies a behavior to anticipate the future consequences of the action. Studying motor planning in nonhuman primates may provide a better understanding of the roots of human planning abilities. In this study we presented capuchin monkeys (Sapajus apella) with a horizontal dowel baited on either the left or right end. A radial grasp on the dowel with the thumb facing toward the baited end would be the most efficient grip selection when bringing the dowel to one's mouth and indicate motor planning. Ten of the 12 monkeys tested spontaneously used a radial grasp significantly more often than expected by chance. Results demonstrate a more ubiquitous expression of motor planning abilities than previously seen in capuchin monkeys. Adaptation of this method of testing may be useful in evaluating motor planning capacity in other primates. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

American Journal of Primatology, 2015

Reduced space can lead to crowding in social animals. Crowding increases the risk of agonistic in... more Reduced space can lead to crowding in social animals. Crowding increases the risk of agonistic interactions that, in turn, may require additional physiological defensive coping mechanisms affecting health. To determine the stress induced from increased social density in a group of nineteen baboons living in an indoor/outdoor enclosure, saliva cortisol levels and rates of anxiety-related behavior were analyzed across two unique crowding episodes. Initially, mean salivary cortisol levels when animals were restricted to their indoor quarters were compared to those when they also had access to their larger outdoor enclosure. Then, mean cortisol levels were compared before, during, and after two distinct crowding periods of long and short duration. Crowding resulted in significantly elevated cortisol during crowding periods compared to non-crowded periods. Cortisol levels returned to baseline following two crowding episodes contrasting in their length and ambient climate conditions. These cortisol elevations indicate greater metabolic costs of maintaining homeostasis under social stress resulting from reduced space. Self-directed behavior, conversely, was not reliably elevated during crowding. Results suggest that the potential for negative social interactions, and/or the uncertainty associated with social threat can cause physiological stress responses detected by salivary cortisol. Self-directed behavioral measures of stress may constitute inadequate indicators of social stress in colony-housed monkeys or represent subjective emotional arousal unrelated to hypothalamic-pituitary adrenal axis activation. Am. J. Primatol. 77:462-467, 2015. © 2015 Wiley Periodicals, Inc.

Scientific American, 2000

Journal of Experimental Psychology: Animal Behavior Processes, 2005

Using techniques established by E. M. Brannon and H. S. Terrace (2000) with rhesus macaques (Maca... more Using techniques established by E. M. Brannon and H. S. Terrace (2000) with rhesus macaques (Macaca mulatta), the authors tested the ability of brown capuchins (Cebus apella) to order arrays of items ranging in quantity from 1 to 9. Three monkeys were trained on a touch screen to select the quantities 1-4 in ascending order. The monkeys exhibited successful transfer of this ability to novel representations of the quantities 1-4 and to pairs of the novel quantities 5-9. Patterns of responding with respect to numeric distance and magnitude were similar to those seen in human subjects, suggesting the use of similar psychological processes. The capuchins demonstrated an ordinal representation of quantity equivalent to that shown in Old World monkeys.

Folia Primatologica, 1994

Intergroup affiliation among female rhesus macaques, Macaca mulatta, was examined in the captive ... more Intergroup affiliation among female rhesus macaques, Macaca mulatta, was examined in the captive free-ranging colony of Morgan Island, S.C., USA. The provisioned colony has many social groups (35) and is maintained at a relatively high population density (21 animals/ha) with a relatively low adult male to female ratio (1:8.8). Focal and ad libitum samples were collected on 32 adults (3 males and 29 females) from two groups. Although infrequent, grooming was observed between adult females from different groups, and alpha females were the main participants in these interactions. Colony records indicated that none of the intergroup grooms was between females formerly from a common group. Relations between familiar neighboring groups may be maintained by a combination of both affiliative and aggressive behavior.

Behavioural Brain Research, 2011

In humans and several nonhuman animals, repetitive behavior is associated with deficits on execut... more In humans and several nonhuman animals, repetitive behavior is associated with deficits on executive function tasks involving response inhibition. We tested for this relationship in nonhuman primates by correlating rates of normative behavior to performance on a reversal-learning task in which animals were required to inhibit a previously learned rule. We focused on rates of self-directed behavior (scratch, autogroom, self touch and manipulation) because these responses are known indicators of arousal or anxiety in primates, however, we also examined rates of other categories of behavior (e.g., locomotion). Behavior rates were obtained from 14 animals representing three nonhuman primate species (Macaca silenus, Saimiri sciureus, Cebus apella) living in separate social groups. The same animals were tested on a reversal-learning task in which they were presented with a black and a grey square on a touch screen and were trained to touch the black square. Once animals learned to select the black square, reward contingencies were reversed and animals were rewarded for selecting the grey square. Performance on the reversal-learning task was positively correlated to self-directed behavior in that animals that exhibited higher rates of self-directed behavior required more trials to achieve reversal. Reversal learning was not correlated to rates of any other category of behavior. Results indicate that rates of behavior associated with anxiety and arousal provide an indicator of executive function in nonhuman primates. The relationship suggests continuity between nonhuman primates and humans in the link between executive functioning and repetitive behavior.

Animal Behaviour, 2013

This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/authorsrights

Tool-use requires the manipulation of an object in the environment to achieve a goal, and the abi... more Tool-use requires the manipulation of an object in the environment to achieve a goal, and the ability to relate one object to another. We used a two-choice tool task to test for comprehension of tool use in three lion-tailed macaques. First, we investigated their comprehension of tool-object relations by presenting a choice between two hook-shaped tools, one of which was baited with a food reward inside the hook (the correct choice) and the other had the reward outside the hook. Two of the three subjects reached criterion (10 out of 12 correct, in 2 consecutive sessions) in 20 sessions, and the third reached criterion in 40 sessions. The second experiment introduced parabola-shaped tools to test whether the subjects could generalize to new tools. All subjects reached criterion in 12 sessions. The third experiment introduced barriers to determine if animals understood the relation between a tool, an object (the reward) and another object in the environment. Subjects needed to choose the tool that was not impeded by a barrier. Two of the three subjects reached criterion in 50 sessions, and the third did not reach criterion in 50 sessions. Results indicated that lion-tailed macaques understood the causal relations between tools and the objects on which they were acting. The design provided a standardized means to compare tool use comprehension across many primate species.

This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/authorsrights

International Journal of Comparative Psychology, 2013

Author(s): Judge, Peter G.; Essler, Jennifer L. | Abstract: Self-control is a prerequisite for co... more Author(s): Judge, Peter G.; Essler, Jennifer L. | Abstract: Self-control is a prerequisite for complex cognitive processes such as cooperation and planning. As such, comparative studies of self-control may help elucidate the evolutionary origin of these capacities. A variety of methods have been developed to test for self-control in non-human primates that include some variation of foregoing an immediate reward in order to gain a more favorable reward. We used a token exchange paradigm to test for self-control in capuchin monkeys (Cebus apella). Animals were trained that particular tokens could be exchanged for food items worth different values. To test for self-control, a monkey was provided with a token that was associated with a lower-value food. When the monkey exchanged the token, the experimenter provided the monkey with a choice between the lower-value food item associated with the token or another token that was associated with a higher-value food. If the monkey chose the to...

American Journal of Primatology, 1993

... than their male age peers [Bercovitch, 1983; Clark, 1978; Eaton et al., 1981; Hor-rocks &... more ... than their male age peers [Bercovitch, 1983; Clark, 1978; Eaton et al., 1981; Hor-rocks & Hunte, 1983; Loy et al ... Bernstein and Ehardt [ 19861 suggested few differences in agonistic behavior among juvenile rhesus monkeys, and that adult males selectively interfere in agonistic ...

International Journal of Comparative Psychology, 2013

American Journal of Primatology, 1991

Journal of Comparative Psychology, 2015

Previous research has suggested that several primate species may be capable of reasoning by exclu... more Previous research has suggested that several primate species may be capable of reasoning by exclusion based on the finding that they can locate a hidden object when given information about where the object is not. The present research replicated and extended the literature by testing 2 Old World monkey species, lion-tailed macaques (Macaca silenus) and a hamadryas baboon (Papio hamadryas), and 2 New World species, capuchin monkeys (Sapajus apella) and squirrel monkeys (Saimiri sciureus). The New World monkeys were tested on the traditional 2-way object choice task, and all 4 species were also tested on a more complex 3-way object choice task. In addition, the squirrel monkeys were tested on a 2-way object choice task with auditory information. The results showed that, whereas the Old World species were able to infer by exclusion on the 3-object task, some of the capuchin monkeys had difficulty on each of the 2- and 3-cup tasks. All but 1 of the squirrel monkeys failed to infer successfully, and their strategies appeared to differ between the visual and auditory versions of the task. Taken together, this research suggests that the ability to succeed on this inference task may be present throughout Old World monkey species, but is fragile in the New World species tested thus far. (PsycINFO Database Record

Journal of Comparative Psychology, 2015

Motor planning is a relatively complex cognitive skill in which an actor modifies a behavior to a... more Motor planning is a relatively complex cognitive skill in which an actor modifies a behavior to anticipate the future consequences of the action. Studying motor planning in nonhuman primates may provide a better understanding of the roots of human planning abilities. In this study we presented capuchin monkeys (Sapajus apella) with a horizontal dowel baited on either the left or right end. A radial grasp on the dowel with the thumb facing toward the baited end would be the most efficient grip selection when bringing the dowel to one's mouth and indicate motor planning. Ten of the 12 monkeys tested spontaneously used a radial grasp significantly more often than expected by chance. Results demonstrate a more ubiquitous expression of motor planning abilities than previously seen in capuchin monkeys. Adaptation of this method of testing may be useful in evaluating motor planning capacity in other primates. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

American Journal of Primatology, 2015

Reduced space can lead to crowding in social animals. Crowding increases the risk of agonistic in... more Reduced space can lead to crowding in social animals. Crowding increases the risk of agonistic interactions that, in turn, may require additional physiological defensive coping mechanisms affecting health. To determine the stress induced from increased social density in a group of nineteen baboons living in an indoor/outdoor enclosure, saliva cortisol levels and rates of anxiety-related behavior were analyzed across two unique crowding episodes. Initially, mean salivary cortisol levels when animals were restricted to their indoor quarters were compared to those when they also had access to their larger outdoor enclosure. Then, mean cortisol levels were compared before, during, and after two distinct crowding periods of long and short duration. Crowding resulted in significantly elevated cortisol during crowding periods compared to non-crowded periods. Cortisol levels returned to baseline following two crowding episodes contrasting in their length and ambient climate conditions. These cortisol elevations indicate greater metabolic costs of maintaining homeostasis under social stress resulting from reduced space. Self-directed behavior, conversely, was not reliably elevated during crowding. Results suggest that the potential for negative social interactions, and/or the uncertainty associated with social threat can cause physiological stress responses detected by salivary cortisol. Self-directed behavioral measures of stress may constitute inadequate indicators of social stress in colony-housed monkeys or represent subjective emotional arousal unrelated to hypothalamic-pituitary adrenal axis activation. Am. J. Primatol. 77:462-467, 2015. © 2015 Wiley Periodicals, Inc.

Scientific American, 2000

Journal of Experimental Psychology: Animal Behavior Processes, 2005

Using techniques established by E. M. Brannon and H. S. Terrace (2000) with rhesus macaques (Maca... more Using techniques established by E. M. Brannon and H. S. Terrace (2000) with rhesus macaques (Macaca mulatta), the authors tested the ability of brown capuchins (Cebus apella) to order arrays of items ranging in quantity from 1 to 9. Three monkeys were trained on a touch screen to select the quantities 1-4 in ascending order. The monkeys exhibited successful transfer of this ability to novel representations of the quantities 1-4 and to pairs of the novel quantities 5-9. Patterns of responding with respect to numeric distance and magnitude were similar to those seen in human subjects, suggesting the use of similar psychological processes. The capuchins demonstrated an ordinal representation of quantity equivalent to that shown in Old World monkeys.

Folia Primatologica, 1994

Intergroup affiliation among female rhesus macaques, Macaca mulatta, was examined in the captive ... more Intergroup affiliation among female rhesus macaques, Macaca mulatta, was examined in the captive free-ranging colony of Morgan Island, S.C., USA. The provisioned colony has many social groups (35) and is maintained at a relatively high population density (21 animals/ha) with a relatively low adult male to female ratio (1:8.8). Focal and ad libitum samples were collected on 32 adults (3 males and 29 females) from two groups. Although infrequent, grooming was observed between adult females from different groups, and alpha females were the main participants in these interactions. Colony records indicated that none of the intergroup grooms was between females formerly from a common group. Relations between familiar neighboring groups may be maintained by a combination of both affiliative and aggressive behavior.

Behavioural Brain Research, 2011

In humans and several nonhuman animals, repetitive behavior is associated with deficits on execut... more In humans and several nonhuman animals, repetitive behavior is associated with deficits on executive function tasks involving response inhibition. We tested for this relationship in nonhuman primates by correlating rates of normative behavior to performance on a reversal-learning task in which animals were required to inhibit a previously learned rule. We focused on rates of self-directed behavior (scratch, autogroom, self touch and manipulation) because these responses are known indicators of arousal or anxiety in primates, however, we also examined rates of other categories of behavior (e.g., locomotion). Behavior rates were obtained from 14 animals representing three nonhuman primate species (Macaca silenus, Saimiri sciureus, Cebus apella) living in separate social groups. The same animals were tested on a reversal-learning task in which they were presented with a black and a grey square on a touch screen and were trained to touch the black square. Once animals learned to select the black square, reward contingencies were reversed and animals were rewarded for selecting the grey square. Performance on the reversal-learning task was positively correlated to self-directed behavior in that animals that exhibited higher rates of self-directed behavior required more trials to achieve reversal. Reversal learning was not correlated to rates of any other category of behavior. Results indicate that rates of behavior associated with anxiety and arousal provide an indicator of executive function in nonhuman primates. The relationship suggests continuity between nonhuman primates and humans in the link between executive functioning and repetitive behavior.

Animal Behaviour, 2013

This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/authorsrights

Animal Behaviour, 2005

The tendency in primate groups for two opponents to affiliate shortly after a fight has been desc... more The tendency in primate groups for two opponents to affiliate shortly after a fight has been described as dyadic reconciliation. The response has been shown to restore disrupted relationships and curtail ongoing aggression. Rates of self-directed behaviour (e.g. scratching) are positively correlated with anxiety in primates and the rates decline after reconciliation, indicating that the response also functions to reduce postconflict tension. Third parties not involved in an aggressive interaction are also likely to affiliate with one of the combatants subsequent to a fight. Such 'triadic' interactions may also promote conflict resolution when, for instance, the relatives of a victim affiliate with their relative's aggressor. Because aggression in a group influences a bystander's behaviour with combatants, we hypothesized that aggression between two animals would also influence a bystander's behaviour with other bystanders. Such 'quadratic' postconflict interactions might also function to reduce postconflict tension or occur in patterns among kin subgroups to resolve conflict. We tested for quadratic interactions in an 18-member group of captive hamadryas baboons, Papio hamadryas hamadryas. Immediately following a fight, an uninvolved bystander was randomly selected for observation and its affiliative interactions with other bystanders and its displacement activities were recorded for 3 min. Rates of behaviour during these postconflict periods were compared to rates during 3-min baseline periods not preceded by aggression. Bystanders engaged in quadratic interactions by increasing affiliation with other bystanders following aggression. Bystanders directed affiliation to nonkin bystanders that were their preferred social partners. Displacement activities of bystanders were significantly higher during postconflict intervals compared to baseline intervals, and bystander displacement activity levels before affiliative contact with other bystanders were significantly higher than after contact. Apparently, bystanders become tense or anxious after witnessing aggression and affiliate with preferred partners to reduce the arousal.