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)     

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)     

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)     

Spatial cues more salient than color cues in cotton-top tamarins (Saguinus oedipus) reversal learning.

Animals living in stable home ranges have many potential cues to locate food. Spatial and color cues are important for wild Callitrichids (marmosets and tamarins). Field studies have assigned the highest priority to distal spatial cues for determining the location of food resources with color cues serving as a secondary cue to assess relative ripeness, once a food source is located. We tested two hypotheses with captive cotton-top tamarins: (a) Tamarins will demonstrate higher rates of initial learning when rewarded for attending to spatial cues versus color cues. (b) Tamarins will show higher rates of correct responses when transferred from color cues to spatial cues than from spatial cues to color cues. The results supported both hypotheses. Tamarins rewarded based on spatial location made significantly more correct choices and fewer errors than tamarins rewarded based on color cues during initial learning. Furthermore, tamarins trained on color cues showed significantly increased correct responses and decreased errors when cues were reversed to reward spatial cues. Subsequent reversal to color cues induced a regression in performance. For tamarins spatial cues appear more salient than color cues in a foraging task. (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)     

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)     

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)     

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)     

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)     

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)     

The role of reference points in ordinal numerical comparisons by rhesus macaques (macaca mulatta).

Two experiments examined ordinal numerical knowledge in rhesus macaques (Macaca mulatta). Experiment 1 replicated the finding (E. M. Brannon & H. S. Terrace, 2000) that monkeys trained to respond in descending numerical order (4→3→2→1) did not generalize the descending rule to the novel values 5-9 in contrast to monkeys trained to respond in ascending order. Experiment 2 examined whether the failure to generalize a descending rule was due to the direction of the training sequence or to the specific values used in the training sequence. Results implicated 3 factors that characterize a monkey's numerical comparison process: Weber's law, knowledge of ordinal direction, and a comparison of each value in a test pair with the reference point established by the first value of the training sequence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Brief Maternal Interaction Increases Number, Amplitude, and Bout Size of Isolation-Induced Ultrasonic Vocalizations in Infant Rats (Rattus norvegicus).

The number, amplitude, duration, and bout structure of isolation-induced ultrasonic vocalization (USV) of infant rats (Rattus norvegicus) were measured on postnatal Day 10. Measurements were made before and after a brief, 1-min, active interaction with their mother or before and after a "pick-up" control procedure. Consistent with prior studies, the number of USVs emitted was significantly increased in the period following the maternal reunion but not after the control procedure. The average amplitude of USVs was also greater following maternal reunion. Finally, analyses characterizing the bout structure of USV production indicated that the average bout size (i.e.. number of USVs/bout) was increased severalfold following the reunion with the mother, accounting for the greater rate of USV production during the second isolation period. (PsycINFO Database Record (c) 2010 APA, all rights reserved)