Journal Cover Journal of Comparative Psychology
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   ISSN (Print) 0735-7036 - ISSN (Online) 1939-2087
   Published by APA Homepage  [74 journals]
  • Common marmoset (Callithrix jacchus) personality.
    • Abstract: Increasing evidence suggests that personality structure differs between species, but the evolutionary reasons for this variation are not fully understood. We built on earlier research on New World monkeys to further elucidate the evolution of personality structure in primates. We therefore examined personality in 100 family-reared adult common marmosets (Callithrix jacchus) from 3 colonies on a 60-item questionnaire. Principal components analyses revealed 5 domains that were largely similar to those found in a previous study on captive, ex-pet, or formerly laboratory-housed marmosets that were housed in a sanctuary. The interrater reliabilities of domain scores were consistent with the interrater reliabilities of domain scores found in other species, including humans. Four domainsdmdash;conscientiousness, agreeableness, inquisitiveness, and assertiveness—resembled personality domains identified in other nonhuman primates. The remaining domain, patience, was specific to common marmosets. We used linear models to test for sex and age differences in the personality domains. Males were lower than females in patience, and this difference was smaller in older marmosets. Older marmosets were lower in inquisitiveness. Finally, older males and younger females had higher scores in agreeableness than younger males and older females. These findings suggest that cooperative breeding may have promoted the evolution of social cognition and influenced the structure of marmoset prosocial personality characteristics. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
      PubDate: Thu, 12 Oct 2017 04:00:00 GMT
  • Kea (Nestor notabilis) decide early when to wait in food exchange
    • Abstract: The ability to forego an immediate reward in favor of a bigger or better one at a later point has been linked with advanced cognitive skills, such as impulse control and forward-planning, and can be assessed by the classic food exchange paradigm. While the ability to perform in such tasks has long been regarded as an exclusive trait of humans and some mammals, that is, primates and dogs, in recent years some bird species have been found to perform similarly as primates. Here we test 10 captive kea (Nestor notabilis), using a food exchange paradigm standardized in earlier experiments, but adding the use of a container to hold the initial item. The subjects reached waiting times of up to 160 s. They also showed significantly different results depending on the difference in the preference level for the presented food items, as well as clearly nonrandom waiting times, displaying forward-planning and economic evaluation of the situation at hand. As in most other species, results were markedly better when exchanging for quality as opposed to quantity. These results provide further evidence for temporal discounting in birds and fit in with the data gained on corvids and parrots in recent years. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
      PubDate: Thu, 31 Aug 2017 04:00:00 GMT
  • Action-matching biases in monkeys (Sapajus spp.) in a stimulus–response
           compatibility task: Evaluating experience-dependent malleability.
    • Abstract: Stimulus–response (S–R) compatibility effects occur when observing certain stimuli facilitate the performance of a related response and interfere with performing an incompatible or different response. Using stimulus–response action pairings, this phenomenon has been used to study imitation effects in humans, and here we use a similar procedure to examine imitative biases in nonhuman primates. Eight capuchin monkeys (Sapajus spp.) were trained to perform hand and mouth actions in a stimulus–response compatibility task. Monkeys rewarded for performing a compatible action (i.e., using their hand or mouth to perform an action after observing an experimenter use the same effector) performed significantly better than those rewarded for incompatible actions (i.e., performing an action after observing an experimenter use the other effector), suggesting an initial bias for imitative action over an incompatible S–R pairing. After a predetermined number of trials, reward contingencies were reversed; that is, monkeys initially rewarded for compatible responses were now rewarded for incompatible responses, and vice versa. In this 2nd training stage, no difference in performance was identified between monkeys rewarded for compatible or incompatible actions, suggesting any imitative biases were now absent. In a 2nd experiment, 2 monkeys learned both compatible and incompatible reward contingencies in a series of learning reversals. Overall, no difference in performance ability could be attributed to the type of rule (compatible–incompatible) being rewarded. Together, these results suggest that monkeys exhibit a weak bias toward action copying, which (in line with findings from humans) can largely be eliminated through counterimitative experience. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
      PubDate: Thu, 31 Aug 2017 04:00:00 GMT
  • On the clock: Interval timing and overshadowing in domestic dogs
           (Canis familiaris).
    • Abstract: Interval timing is an important skill that allows animals to approximate how much time has elapsed since a given event. Little, however, is known about interval timing in domestic dogs. In an initial experiment, dogs were trained to make an operant response on 30-s fixed intervals, with either a light or a tone + light compound signaling the beginning of the fixed interval. When dogs in the compound group were subsequently tested with nonreinforced 60-s tone-only probe trials, the dogs’ rate of responding peaked near 30 s. When the same dogs were tested with light-only probes, however, no evidence of timing was found. In a second experiment, a bisection task was used in which dogs had to learn to approach 1 feeder when given an 8-s tone + light signal, and another feeder when given a 2-s tone + light signal. When subsequently tested at intermediate durations, psychophysical curves showed clear control of timing by the tone stimulus but not by the light stimulus. These findings clearly demonstrate that dogs are able to time fixed intervals and show the existence of an overshadowing effect, in which dogs are able to time a light cue presented alone but do not attend to the light when it is presented simultaneously with a tone. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
      PubDate: Thu, 31 Aug 2017 04:00:00 GMT
  • Piagetian liquid conservation in grey parrots (Psittacus
    • Abstract: An understanding of Piagetian liquid conservation was investigated in four Grey parrots (Psittacus erithacus), their ages ranging from initially less than 1 year old to 18 years old. They were tested in several conditions: on the ability to choose between (a) identical containers filled with a greater or lesser quantity of a desirable liquid to see if they would reliably take the larger amount and (b) equal quantities of liquid that were visibly or invisibly transferred from identical to different-sized containers to examine their abilities with respect to conservation. Invisible transfers examined the extent to which birds chose based on perceptual evaluations of quantity and the effects of task order on their decisions. Adult birds succeeded on all or most aspects of the tests. As a chick (∼6 months), 1 bird was unable or unwilling to choose between the smaller and larger quantities in the first stage of testing, but upon reaching juvenile status succeeded in all aspects of the tests. Grey parrots thus demonstrate some understanding of liquid conservation. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
      PubDate: Thu, 31 Aug 2017 04:00:00 GMT
  • Slope-based and geometric encoding of a goal location by the terrestrial
           toad (Rhinella arenarum).
    • Abstract: The current study was designed to test for the ability of terrestrial toads, Rhinella arenarum, to use slope as source of spatial information to locate a goal, and investigate the relative importance of slope and geometric information for goal localization. Toads were trained to locate a single, water-reward goal location in a corner of a rectangular arena placed on an incline. Once the toads learned the task, 3 types of probe trials were carried out to determine the relative use of slope and geometric information for goal localization. The probe trials revealed that the toads were able to independently use slope, and as previously reported, geometry to locate the goal. However, the boundary geometry of the experimental arena was found to be preferentially used by the toads when geometric and slope information were set in conflict. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
      PubDate: Mon, 28 Aug 2017 04:00:00 GMT
  • Spatial transposition tasks in Indian sloth bears (Melursus ursinus) and
           Bornean sun bears (Helarctos malayanus euryspilus).
    • Abstract: Spatial transposition tasks assess individuals’ ability to represent nonvisible spatial object displacements. Several nonhuman mammal species have been tested on this task including primates, cats, and dogs, but to date, great apes seem the only taxon that has repeatedly and consistently solved spatial transposition tasks. The authors investigated the ability of captive sloth and sun bears to solve spatial transposition tasks. Both species belong to the same taxonomic group as cats and dogs, but unlike them and similar to apes, they have an omnivorous diet that requires them to keep track of fruit sources in space and time. The bears were first tested on a visible displacement task and those that succeeded were further tested on a spatial transposition task that involved a 180° transposition, followed by 2 tasks with two 360° transpositions. All 7 sloth bears and 7 out of 9 sun bears solved the visible displacement task. The 180° transposition task was solved by 6 out of 7 sloth bears and 1 out of the 5 tested sun bears. Three sloth bears were tested on all 4 experiments and even solved 2-chained 360° transpositions. Control conditions were conducted showing that the bears’ performance did not rely on olfactory or auditory cues. The results provide the first indication that bears might be able to track invisible objects. Further studies will be necessary to confirm these results and to control the influence of associative learning. The present study emphasizes the importance of including different animal species in the investigation of what underlies the evolution of different cognitive skills. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
      PubDate: Mon, 26 Jun 2017 04:00:00 GMT
  • Visible spatial contiguity of social information and reward affects social
    • Abstract: Animal social learning is typically studied experimentally by the presentation of artificial foraging tasks. Although productive, results are often variable even for the same species. We present and test the hypothesis that one cause of variation is that spatial distance between rewards and the means of reward release causes conflicts for participants’ attentional focus. We investigated whether spatial contiguity between a visible reward and the means of release would affect behavioral responses that evidence social learning, testing 21 brown capuchins (Sapajus apella), a much-studied species with variant evidence for social learning, and one hundred eighty 2- to 4-year-old human children (Homo sapiens), a benchmark species known for a strong social learning disposition. Participants were presented with a novel transparent apparatus where a reward was either proximal or distal to a demonstrated means of releasing it. A distal reward location decreased attention toward the location of the demonstration and impaired subsequent success in gaining rewards. Generally, the capuchins produced the alternative method to that demonstrated, whereas children copied the method demonstrated, although a distal reward location reduced copying in younger children. We conclude that some design features in common social learning tasks may significantly degrade the evidence for social learning. We have demonstrated this for 2 different primates but suggest that it is a significant factor to control for in social learning research across all taxa. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
      PubDate: Thu, 25 May 2017 04:00:00 GMT
  • Cognitive bias and paw preference in the domestic dog (Canis
    • Abstract: Limb use, an indicator of hemispheric functioning, may be a useful predictor of cognitive bias and hence vulnerability to welfare risk. The relationship between cognitive bias and motor asymmetry, however, has been subject to little investigation. This study explored the association between motor asymmetry and cognitive bias in the domestic dog, a species that displays lateral bias in the form of paw preferences and exhibits positive and negative affective states. Thirty pet dogs had their paw preferences assessed using the Kong ball test. The subjects’ affective state was assessed using a cognitive bias test in which the animals’ latency to approach a bowl placed in 1 of 3 ambiguous positions was recorded. Animals veering more toward a left-paw preference were found to be significantly slower to approach the bowl placed in 1 of the ambiguous positions than ambilateral or right-pawed dogs. Left-pawed subjects approached the bowl located at the 3 ambiguous positions at roughly the same speed, while ambilateral and right-pawed animals became increasingly slower to approach the bowl the further it was located from the baited food bowl. The study points to a possible relationship between cognitive bias and paw preference in the dog, with left-pawed animals being more negative or “pessimistic” in their cognitive outlook than right-pawed or ambilateral individuals. It is proposed that limb preference testing might offer a more practical and straightforward way of identifying individuals at risk from poor welfare by virtue of how they perceive the world than more time-consuming cognitive bias tests. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
      PubDate: Thu, 18 May 2017 04:00:00 GMT
  • Do pigeons (Columba livia) use information about the absence of food
           appropriately' A further look into suboptimal choice.
    • Abstract: In the natural environment, when an animal encounters a stimulus that signals the absence of food—a ‘bad-news’ stimulus—it will most likely redirect its search to another patch or prey. Because the animal does not pay the opportunity cost of waiting in the presence of a bad-news stimulus, the properties of the stimulus (e.g., its duration and probability) may have little impact in the evolution of the decision processes deployed in these circumstances. Hence, in the laboratory, when animals are forced to experience a bad-news stimulus they seem to ignore its duration, even though they pay the cost of waiting. Under certain circumstances, this insensitivity to the opportunity cost can lead to suboptimal preferences, such as a preference for an option yielding a low rather than a high rate of reinforcement. In 2 experiments, we tested Vasconcelos, Monteiro, and Kacelnik’s (2015) assumption that, if given the opportunity, animals will escape the bad-news stimulus. To predict when an escape response should occur, we incorporated ideas from the prey choice model into Vasconcelos et al. (2015) model and made 2 novel predictions. Namely, both longer intertrial intervals and longer durations of signals predicting food or no food should lead to higher proportions of escape responses. The results of 2 experiments with pigeons supported these predictions. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
      PubDate: Mon, 08 May 2017 04:00:00 GMT
  • Visual acuity in the striped skunk (Mephitis mephitis).
    • Abstract: The visual acuity of striped skunks (Mephitis mephitis) was tested using a 2 alternative forced-choice task with square wave gratings. Skunks were reinforced with food items for touching a ball in front of a striped stimulus when paired with a ball in front of a solid gray stimulus. Skunks demonstrated a maximum visual acuity of 0.42 cycles per degree when tested with bright outdoor illumination. This poor visual acuity may be due to their nocturnal lifestyle, lack of predation, and is consistent with their preferential use of smell and sound during foraging. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
      PubDate: Thu, 23 Mar 2017 04:00:00 GMT
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