Long-term memory for calls of relatives in cotton-top tamarins (Saguinus oedipus).

Recognition of relatives is important for dispersing animals to avoid inbreeding and possibly for developing cooperative, reciprocal relationships between individuals after dispersal. We demonstrate under controlled captive conditions that cotton-top tamarins (Saguinus oedipus) have a long-term memory for long calls of relatives from which they had been separated for periods ranging from 4 to 55 months. Tamarins responded with lower levels of arousal behavior to playbacks of long calls from current mates and from separated relatives compared to calls of unfamiliar, unrelated tamarins. Four tamarins had been out of contact with relatives for more than 4 years and still showed recognition as evidenced by low levels of arousal. Results could not be explained in terms of proximity to former relatives. Long-term memory for vocal signatures of relatives is adaptive and may be much more common than has been demonstrated. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Social communication about unpalatable foods in tamarins (Saguinus oedipus).

Many monkeys show social facilitation in sampling novel, palatable foods but not in avoiding unpalatable foods. Cotton-top tamarins (Saguinus oedipus) socially learned to avoid a preferred food when it was made unpalatable but showed no aversion toward a food not made unpalatable. Only 33% sampled unpalatable tuna, and few sampled it again. In 3 of 8 groups, the socially induced aversion was long lasting, at least 15 weeks after food was made palatable again. Potential cues include facial reactions of disgust, alarm-call vocalizations, and reduction in food-associated calls. Behavioral coordination in cooperative infant care, communication about food, and well-established social relationships may explain social avoidance of unpalatable foods in tamarins and the absence of social avoidance in less cooperative species. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spontaneous representation of number in cotton-top tamarins ( Saguinus oedipus).

The "violation of expectancy" looking-time methodology has proven a powerful tool for exploring prelinguistic mental representations in human infants as well as in nonhuman primates. Four studies applying this methodology to the question of spontaneous number representations in cotton-top tamarins (Saguinus oedipus) are reported here. Monkeys were shown 1?+?1 events in which objects were placed behind a screen, 1 by 1. The screen was removed, revealing consistent (2 objects) and inconsistent (1, 3, or 1 large object twice the mass of original object) outcomes. In all studies, monkeys looked longer at the inconsistent than at the consistent outcome. When the monkeys view a 1?+?1 operation, they expect exactly 2 objects. It is likely that these numerical representations are spontaneously available to a variety of primate species and could provide a foundation on which humans' number sense was constructed over evolution and development. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Implicit chaining in cotton-top tamarins (Saguinus oedipus).

In implicit learning, human subjects are exposed to patterned information, but they are not informed about the pattern. Typically, they demonstrate learning of that pattern, but little awareness of the experimental contingencies. In a nonhuman analog of this procedure, two cotton-top tamarins (Saguinus oedipus) were presented with a five-element chain that consisted of the same icon presented serially at different locations on a touchscreen. The tamarins had to touch the icon at each location to advance the chain and receive reinforcement at the end of the chain. One element of the chain was never differentially reinforced in the presence of another element, as is typically done in transitive inference and serial chaining studies. Following training, the tamarins were tested for their knowledge of the chain using pairwise tests that are common in transitive inference and serial chaining experiments, and a random test, common in some types of implicit learning, in which the sequence of elements was randomized. The results of both tests revealed that the tamarins appreciated the ordinal position of the elements composing the chain, although reinforcement had not been dependent on that knowledge. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

What guides a search for food that has disappeared? Experiments on cotton-top tamarins (Saguinus oedipus).

When food is launched down a vertically positioned S-shaped opaque tube, cotton-top tamarins (Saguinus oedipus) search for the food in the position directly beneath the release point, even though over several trials it never appears in this position (B. M. Hood et al., 1999). Experiment 1 showed that when the trajectory of the food shifts from the vertical to the horizontal plane, tamarins no longer show systematic perseverative errors and, in general, perform better on this invisible displacement task. Experiment 2 showed that tamarins with experience on the horizontal task show less of a bias when tested on the vertical task but nonetheless fail overall to solve this invisible displacement problem; their performance is substantially worse than it was on the horizontal task. Experiment 3 revealed that when the vertically positioned tube is replaced by an occluded ramp, tamarins consistently search in the compartment below the release point, even though most of the tamarins had experience in Experiments 1 and 2. Overall, results indicate that tamarins have a significant gravity bias when searching for food that has disappeared along the vertical plane but also have more general problems finding food that has moved out of sight. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Global and local processing in adult humans (Homo sapiens), 5-year-old children (Homo sapiens), and adult cotton-top tamarins (Saguinus oedipus).

This study compared adults (Homo sapiens), young children (Homo sapiens), and adult tamarins (Saguinus oedipus) while they discriminated global and local properties of stimuli. Subjects were trained to discriminate a circle made of circle elements from a square made of square elements and were tested with circles made of squares and squares made of circles. Adult humans showed a global bias in testing that was unaffected by the density of the elements in the stimuli. Children showed a global bias with dense displays but discriminated by both local and global properties with sparse displays. Adult tamarins' biases matched those of the children. The striking similarity between the perceptual processing of adult monkeys and humans diagnosed with autism and the difference between this and normatively developing human perception is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The production and perception of long calls by cotton-top tamarins (Saguinus oedipus): Acoustic analyses and playback experiments.

Examined the cotton-top tamarin's production and perception of their combination long call (CLC). A series of acoustic analyses designed to determine the kind of information encoded in the CLC was conducted. Using factorial ANOVA and multiple discriminant analyses, identity information encoded in the CLC was explored: individual, sex, and social group. Exemplars could be reliably assigned to these 3 functional classes on the basis of a suite of spectrotemporal features. Second, a series of habituation–dishabituation playback experiments tested whether tamarins attend to the encoded information about individual identity. Tamarins were habituated to a series of calls from 1 tamarin and then played back a test call from a novel tamarin; both opposite- and same-sex pairings were tested. Results showed that tamarins dishabituated when caller identity changed but transferred habituation when caller identity was held constant and a new exemplar was played. Follow-up playback experiments revealed an asymmetry between the acoustic analyses of individual identity and the tamarins' capacity to discriminate among vocal signatures. Whereas all colony members have distinctive vocal signatures, not all tamarins were equally discriminable based on the habituation–dishabituation paradigm. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The relationship between problem solving and inhibitory control: Cotton-top tamarins ( Saguinus oedipus ) performance on a reversed contingency task.

To explore the relationship between problem solving and inhibitory control, the authors present 4 experiments on cotton-top tamarins (Saguinus oedipus) using a reverse-reward contingency task. In Experiment 1, 1 group of tamarins was given a choice between a small and a large quantity of food. Whichever quantity the tamarins reached for first, they received the alternative. The tamarins consistently picked the larger quantity, thereby receiving the smaller. A 2nd group of tamarins was given the same task, except that if they reached for the larger quantity of food, they received nothing. The tamarins continued to pick the larger quantity, even though this resulted in no food. In addition, most of the tamarins continued to pick the larger quantity even when the food payoff for choosing the smaller quantity was increased (Experiment 2) or when the visual salience of the food was reduced (Experiment 3). Experiment 4 was based on the finding that chimpanzees (Pan troglodytes) that have been trained on the concept of number can solve the reversed contingency task if the food is replaced by Arabic numerals. With the help of a color association, and a higher cost incurred by picking the color associated with 3 food items, the tamarins learned to pick the color associated with... (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Laterality in hand preferences and reaching accuracy of cotton-top tamarins (Saguinus oedipus).

Manual laterality of cotton-top tamarins (Saguinus oedipus) was observed for five different types of reaching. The tamarins displayed species-level right-handedness for spontaneous grasping for food but not for one-arm vertical suspension or any of 3 other types of elicited reaching. The results showed that difficult or novel tasks are neither necessary nor sufficient for the emergence of species-level handedness. Accuracy in retrieving food from a rotating platform was greatest (a) for highly lateralized tamarins, (b) when the preferred hands were used for reaching, (c) for young tamarins, and (d) when the tamarins stood on a narrow, unstable platform instead of a wide, stable one. The results suggest that evolution of species-level handedness is dependent on prior natural selection for increased manual performance that accompanies strongly lateralized hand preferences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Use of experimenter-given cues in visual co-orienting and in an object-choice task by a New World monkey species, Cotton Top Tamarins ( Saguinus oedipus ).

Two methods assessed the use of experimenter-given directional cues by a New World monkey species, cotton top tamarins (Saguinus oedipus). Experiment 1 used cues to elicit visual co-orienting toward distal objects. Experiment 2 used cues to generate responses in an object-choice task. Although there were strong positive correlations between monkey pairs to co-orient, visual co-orienting with a human experimenter occurred at a low frequency to distal objects. Human hand pointing cues generated more visual co-orienting than did eye gaze to distal objects. Significant accurate choices of baited cups occurred with human point and tap cues and human look cues. Results highlight the importance of head and body orientation to induce shared attention in cotton top tamarins, both in a task that involved food getting and a task that did not. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Constraints on problem solving and inhibition: Object retrieval in cotton-top tamarins (Saguinus oedipus oedipus).

Problem solving relies on a combination of the capacity to generate appropriate solutions and the ability to inhibit prepotent inappropriate responses. Often, problems with the latter prevent some animals from performing well on problem-solving tasks. The authors used the object retrieval task to examine inhibition in cotton-top tamarins (Saguinus oedipus oedipus). They found that, like human infants, tamarins had difficulty retrieving a reward from inside a transparent box when the opening was on the side because they could not inhibit the tendency to reach straight into the solid face of the box. However, subjects trained with an opaque box prior to testing on the transparent box performed perfectly. These results suggest that although the inability to inhibit prepotent biases prevents individuals from acquiring an initial strategy, sufficient training on an effective strategy may allow animals to overcome their initial difficulties with tasks requiring inhibition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Postural effects on manual reaching laterality in squirrel monkeys (Saimiri sciureus) and cotton-top tamarins (Saguinus oedipus).

Squirrel monkeys (Saimiri sciureus) and cotton-top tamarins (Saguinus oedipus) made unimanual food reaches from either a horizontal, quadrupedal posture or a vertical, clinging posture. No population-level handedness occurred in either species. However, in both species, directional lateral preferences weakly expressed for reaching from the stable quadrupedal posture were intensified in the vertical cling posture. This phenomenon, which is designated as soft handedness, may have been an evolutionary precursor to population-level handedness. Right or left turning by the squirrel monkeys before reaching closely predicted use of the right or left hand. However, the magnitude of the association decreased in the more highly lateralized vertical cling condition. This result suggests that as lateral hand preference increases, hand use may become increasingly independent of constraints from prior behavioral and environmental influences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Is a sense of inequity an ancestral primate trait? Testing social inequity in cotton top tamarins (Saguinus oedipus).

To address a controversy in the literature concerning whether monkeys show an aversion to inequity, individuals of a New World monkey species, cotton top tamarins (Saguinus oedipus) were tested in an offering task and in a bartering task. At issue was whether the monkeys rejected rewards because of a violation of expectancy of the preferred reward, or whether they rejected rewards because of a sensitivity to socially mediated inequity. The data from both tasks indicated that the subjects were more likely to reject when preferred rewards were presented, either because of another animal eating the reward (the social condition) or because of rewards being presented but inaccessible. The bartering task led to the only behavioral indication of aversion due specifically to social inequity, which was demonstrated when tamarins' sensitivity to the difference in rewards increased with exposure to other tamarins working to receive the preferred rewards. The results suggest that social inequity aversion will be assessed by tamarins, and possibly by other primates, only under conditions of limited resources and a requirement of work, which may make the situation a bit more competitive and thus drives attention toward both social and reward evaluation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Impaired learning of a color reversal task after NMDA receptor blockade in the pigeon (Columbia livia) associative forebrain (Neostriatum Caudolaterale).

The neostriatum caudolaterale (NCL) in the pigeon (Columba livia) forebrain is a multisensory associative area and a functional equivalent to the mammalian prefrontal cortex (PFC). To investigate the role of N-methyl-{D}-aspartate (NMDA) receptors in the NCL for learning flexibility, the authors trained pigeons in a color reversal task while locally blocking NMDA receptors with {D},{L}-2-2-amino-5phosphorrovalerate (AP-5). Controls received saline injections. AP-5-treated pigeons made significantly more errors and showed significantly stronger perseveration in a learning strategy applied by both groups but were unimpaired in initial learning. Results indicate that NMDA receptors in the NCL are necessary for efficient performance in this PFC-sensitive task, and that they are involved in extinction of obsolete information rather than in acquiring new information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hysteresis effects in a motor task with cotton-top tamarins (Sanguinus oedipus).

The way human adults grasp an object is influenced by their recent history of motor actions. Previously executed grasps are often more likely to reoccur on subsequent grasps. This type of hysteresis effect has been incorporated into cognitive models of motor planning, suggesting that when planning movements, individuals tend to reuse recently used plans rather than generating new plans from scratch. To the best of our knowledge, the phylogenetic roots of this phenomenon have not been investigated. Here, the authors asked whether 6 cotton-top tamarin monkeys (Saguinus oedipus) would demonstrate a hysteresis effect on a reaching task. The authors tested the monkeys by placing marshmallow pieces within grasping distance of a hole through which the monkeys could reach. On subsequent trials, the marshmallow position changed such that it progressed in an arc in either a clockwise or counterclockwise direction. The authors asked whether the transition point in right- versus left-handed reaches would differ depending on the direction of the progression. The data supported this hysteresis prediction. The outcome provides additional support for the notion that human motor planning strategies may have a lengthy evolutionary history. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tracking responses related to self-recognition: A frequency comparison of responses to mirrors, photographs, and videotapes by cotton top tamarins (Saguinus oedipus).

The frequency of responses cotton top tamarins (Saguinus oedipus) emitted indicative of self-recognition to a mirror was compared with the frequencies of responses emitted to digitized photographs of tamarins (Experiment 1) and to videotapes of real-time or prior tamarin action (Experiment 2). Results indicated more attentional responses toward the mirror in both studies, but behavioral indices of self-recognition were not consistently generated by the mirror. The 2 experiments confirmed that real-time self-reflection is a condition that generates heightened attention and ram examples of particular mirror-specific behaviors in tamarins. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cooperatively breeding cottontop tamarins (Saguinus oedipus) do not donate rewards to their long-term mates.

This study tested the hypothesis that cooperative breeding facilitates the emergence of prosocial behavior by presenting cottontop tamarins (Saguinus oedipus) with the option to provide food rewards to pair-bonded mates. In Experiment 1, tamarins could provide rewards to mates at no additional cost while obtaining rewards for themselves. Contrary to the hypothesis, tamarins did not demonstrate a preference to donate rewards, behaving similar to chimpanzees in previous studies. In Experiment 2, the authors eliminated rewards for the donor for a stricter test of prosocial behavior, while reducing separation distress and food preoccupation. Again, the authors found no evidence for a donation preference. Furthermore, tamarins were significantly less likely to deliver rewards to mates when the mate displayed interest in the reward. The results of this study contrast with those recently reported for cooperatively breeding common marmosets, and indicate that prosocial preferences in a food donation task do not emerge in all cooperative breeders. In previous studies, cottontop tamarins have cooperated and reciprocated to obtain food rewards; the current findings sharpen understanding of the boundaries of cottontop tamarins’ food-provisioning behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Choosing and Using Tools: Capuchins (Cebus apella) Use a Different Metric Than Tamarins (Saguinus oedipus).

Cotton-top tamarins (Saguinus oedipus) selected canes positioned so that a straight inward pull brought food within reach (M. D. Hauser, 1997; see also record 1997-41347-003). Tamarins failed to retrieve food with canes in other positions, and they did not reposition these canes. In this study, tufted capuchin monkeys (Cebus apella) preferred canes they could pull straight in when these were present, but they also repositioned canes in individually variable ways, and their success at obtaining food with repositioned canes improved with practice. In accord with predictions drawn from ecological psychology, capuchins discovered affordances of canes through exploratory actions with these objects, whereas tamarins did not. Ecological theory predicts these differences on the basis of species-typical manipulative activity, and it provides a useful approach for the study of species differences in tool-using behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Location serves as a conditional cue when harp seals (Pagophilus groenlandicus) solve object discrimination reversal problems.

We examined the capacity of harp seals (Pagophilus groenlandicus) to use spatial context (i.e., their tank) as a conditional cue to solve a two-choice visual discrimination reversal task. Seals were trained to touch one of two 3D objects. Two of four seals experienced a context shift that coincided with each of five reversals in the reward value of the two stimuli (i.e., a reversal of S+ and S-); these seals solved the six discriminations in significantly fewer trials than did seals that did not experience a context shift with the contingency reversal. Thus, harp seals use contextual cues when encoding information. The findings are discussed in terms of harp seals' adaptations to the pack-ice environment, the constraints of the learning tasks, and the nature of the subjects that were raised in captivity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Social cues influence foraging in dwarf hamsters (Phodopus campbelli).

In 2 experiments, dwarf hamsters (Phodopus campbelli) were trained to find palatable foods in an open field. The location of each food patch remained the same throughout each experiment, and only 1 food was available per day. Once subjects had been trained to find each food in its unique location, they progressed to a testing phase in which subjects’ mates were allowed to eat and hoard the food that was available in the open field each day. The foods that subjects’ mates brought back to the home cages then served as discriminative stimuli signaling which food could be obtained in the open field. Subjects generally approached the patch containing the food hoarded by their mates, suggesting that dwarf hamster burrows could function as information centers. (PsycINFO Database Record (c) 2010 APA, all rights reserved)