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Sutton, J. E., & Shettleworth, S. J. (2005). Internal sense of direction and landmark use in pigeons (Columba livia). J Comp Psychol, 119(3), 273–284.
Abstract: The relative importance of an internal sense of direction based on inertial cues and landmark piloting for small-scale navigation by White King pigeons (Columba livia) was investigated in an arena search task. Two groups of pigeons differed in whether they had access to visual cues outside the arena. In Experiment 1, pigeons were given experience with 2 different entrances and all pigeons transferred accurate searching to novel entrances. Explicit disorientation before entering did not affect accuracy. In Experiments 2-4, landmarks and inertial cues were put in conflict or tested 1 at a time. Pigeons tended to follow the landmarks in a conflict situation but could use an internal sense of direction to search when landmarks were unavailable.
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Hare, B., Plyusnina, I., Ignacio, N., Schepina, O., Stepika, A., Wrangham, R., et al. (2005). Social cognitive evolution in captive foxes is a correlated by-product of experimental domestication. Curr Biol, 15(3), 226–230.
Abstract: Dogs have an unusual ability for reading human communicative gestures (e.g., pointing) in comparison to either nonhuman primates (including chimpanzees) or wolves . Although this unusual communicative ability seems to have evolved during domestication , it is unclear whether this evolution occurred as a result of direct selection for this ability, as previously hypothesized , or as a correlated by-product of selection against fear and aggression toward humans--as is the case with a number of morphological and physiological changes associated with domestication . We show here that fox kits from an experimental population selectively bred over 45 years to approach humans fearlessly and nonaggressively (i.e., experimentally domesticated) are not only as skillful as dog puppies in using human gestures but are also more skilled than fox kits from a second, control population not bred for tame behavior (critically, neither population of foxes was ever bred or tested for their ability to use human gestures) . These results suggest that sociocognitive evolution has occurred in the experimental foxes, and possibly domestic dogs, as a correlated by-product of selection on systems mediating fear and aggression, and it is likely the observed social cognitive evolution did not require direct selection for improved social cognitive ability.
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Harris, E. H., & Washburn, D. A. (2005). Macaques' (Macaca mulatta) use of numerical cues in maze trials. Anim. Cogn., 8(3), 190–199.
Abstract: We tested the ability of number-trained rhesus monkeys to use Arabic numeral cues to discriminate between different series of maze trials and anticipate the final trial in each series. The monkeys' prior experience with numerals also allowed us to investigate spontaneous transfer between series. A total of four monkeys were tested in two experiments. In both experiments, the monkeys were trained on a computerized task consisting of three reinforced maze trials followed by one nonreinforced trial. The goal of the maze was an Arabic numeral 3, which corresponded to the number of reinforced maze trials in the series. In experiment 1 (n=2), the monkeys were given probe trials of the numerals 2 and 4 and in experiment 2 (n=2), they were given probe trials of the numerals 2-8. The monkeys receiving the probe trials 2 and 4 showed some generalization to the new numerals and developed a pattern of performing more slowly on the nonreinforced trial than the reinforced trial before it for most series, indicating the use of the changing numeral cues to anticipate the nonreinforced trial. The monkeys receiving probe trials of the numerals 2-8 did not predict precisely when the nonreinforced trial would occur in each series, but they did incorporate the changing numerals into their strategy for performing the task. This study provides the first evidence that number-trained monkeys can use Arabic numerals to perform a task involving sequential presentations.
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Hodgson, Z. G., & Healy, S. D. (2005). Preference for spatial cues in a non-storing songbird species. Anim. Cogn., 8(3), 211–214.
Abstract: Male mammals typically outperform their conspecific females on spatial tasks. A sex difference in cues used to solve the task could underlie this performance difference as spatial ability is reliant on appropriate cue use. Although comparative studies of memory in food-storing and non-storing birds have examined species differences in cue preference, few studies have investigated differences in cue use within a species. In this study, we used a one-trial associative food-finding task to test for sex differences in cue use in the great tit, Parus major. Birds were trained to locate a food reward hidden in a well covered by a coloured cloth. To determine whether the colour of the cloth or the location of the well was learned during training, the birds were presented with three wells in the test phase: one in the original location, but covered by a cloth of a novel colour, a second in a new location covered with the original cloth and a third in a new location covered by a differently coloured cloth. Both sexes preferentially visited the well in the training location rather than either alternative. As great tits prefer colour cues over spatial cues in one-trial associative conditioning tasks, cue preference appears to be related to the task type rather than being species dependent.
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Barth, J., Reaux, J. E., & Povinelli, D. J. (2005). Chimpanzees' (Pan troglodytes) use of gaze cues in object-choice tasks: different methods yield different results. Anim. Cogn., 8(2), 84–92.
Abstract: To assess the influence of different procedures on chimpanzees' performance in object-choice tasks, five adult chimpanzees were tested using three experimenter-given cues to food location: gazing, glancing, and pointing. These cues were delivered to the subjects in an identical fashion but were deployed within the context of two distinct meta-procedures that have been previously employed with this species with conflicting results. In one procedure, the subjects entered the test unit and approached the experimenter (who had already established the cue) on each trial. In the other procedure, the subjects stayed in the test unit throughout a session, witnessed the hiding procedure, and waited for a delay of 10 s during which the cue was provided. The subjects scored at high levels far exceeding chance in response to the gaze cue only when they approached the experimenter for each trial. They performed at chance levels when they stayed inside the test unit throughout the session. They scored at chance levels on all other cues irrespective of the procedure. These findings imply that (a) chimpanzees can immediately exploit social gaze cues, and (b) previous conflicting findings were likely due to the different meta-procedures that were used.
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Blaisdell, A. P., & Cook, R. G. (2005). Integration of spatial maps in pigeons. Anim. Cogn., 8(1), 7–16.
Abstract: The integration of spatial maps in pigeons was investigated using a spatial analog to sensory preconditioning. The pigeons were tested in an open-field arena in which they had to locate hidden food among a 4x4 grid of gravel-filled cups. In phase 1, the pigeons were exposed to a consistent spatial relationship (vector) between landmark L (a red L-shaped block of wood), landmark T (a blue T-shaped block of wood) and the hidden food goal. In phase 2, the pigeons were then exposed to landmark T with a different spatial vector to the hidden food goal. Following phase 2, pigeons were tested with trials on which they were presented with only landmark L to examine the potential integration of the phase 1 and 2 vectors via their shared common elements. When these test trials were preceded by phase 1 and phase 2 reminder trials, pigeons searched for the goal most often at a location consistent with their integration of the L-->T phase 1 and T-->phase 2 goal vectors. This result indicates that integration of spatial vectors acquired during phases 1 and 2 allowed the pigeons to compute a novel L-->goal vector. This suggests that spatial maps may be enlarged by successively integrating additional spatial information through the linkage of common elements.
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Herrmann, E., Melis, A. P., & Tomasello, M. (2006). Apes' use of iconic cues in the object-choice task. Anim. Cogn., 9(2), 118–130.
Abstract: In previous studies great apes have shown little ability to locate hidden food using a physical marker placed by a human directly on the target location. In this study, we hypothesized that the perceptual similarity between an iconic cue and the hidden reward (baited container) would help apes to infer the location of the food. In the first two experiments, we found that if an iconic cue is given in addition to a spatial/indexical cue – e.g., picture or replica of a banana placed on the target location – apes (chimpanzees, bonobos, orangutans, gorillas) as a group performed above chance. However, we also found in two further experiments that when iconic cues were given on their own without spatial/indexical information (iconic cue held up by human with no diagnostic spatial/indexical information), the apes were back to chance performance. Our overall conclusion is that although iconic information helps apes in the process of searching hidden food, the poor performance found in the last two experiments is due to apes' lack of understanding of the informative (cooperative) communicative intention of the experimenter.
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Chiesa, A. D., Pecchia, T., Tommasi, L., & Vallortigara, G. (2006). Multiple landmarks, the encoding of environmental geometry and the spatial logics of a dual brain. Anim. Cogn., 9(4), 281–293.
Abstract: A series of place learning experiments was carried out in young chicks (Gallus gallus) in order to investigate how the geometry of a landmark array and that of a walled enclosure compete when disoriented animals could rely on both of them to re-orient towards the centre of the enclosure. A square-shaped array (four wooden sticks) was placed in the middle of a square-shaped enclosure, the two structures being concentric. Chicks were trained to ground-scratch to search for food hidden in the centre of the enclosure (and the array). To check for effects of array degradation, one, two, three or all landmarks were removed during test trials. Chicks concentrated their searching activity in the central area of the enclosure, but their accuracy was inversely contingent on the number of landmarks removed; moreover, the landmarks still present within the enclosure appeared to influence the shape of the searching patterns. The reduction in the number of landmarks affected the searching strategy of chicks, suggesting that they had focussed mainly on local cues when landmarks were present within the enclosure. When all the landmarks were removed, chicks searched over a larger area, suggesting an absolute encoding of distances from the local cues and less reliance on the relationships provided by the geometry of the enclosure. Under conditions of monocular vision, chicks tended to rely on different strategies to localize the centre on the basis of the eye (and thus the hemisphere) in use, the left hemisphere attending to details of the environment and the right hemisphere attending to the global shape.
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Church, D. L., & Plowright, C. M. S. (2006). Spatial encoding by bumblebees (Bombus impatiens) of a reward within an artificial flower array. Anim. Cogn., 9(2), 131–140.
Abstract: We presented bumblebees a spatial memory task similar to that used with other species (e.g., cats, dogs, and pigeons). In some conditions we allowed for presence of scent marks in addition to placing local and global spatial cues in conflict. Bumblebees (Bombus impatiens) were presented an array of artificial flowers within a flight cage, one flower offering reward (S+), while the others were empty (S-). Bees were tested with empty flowers. In Experiment 1, flowers were either moved at the time of testing or not. Bees returned to the flower in the same absolute position of the S+ (the flower-array-independent (FAI) position), even if it was in the wrong position relative to the S- and even when new flower covers prevented the use of possible scent marks. New flower covers (i.e., without possible scent marks) had the effect of lowering the frequency of probing behavior. In Experiment 2, the colony was moved between training and testing. Again, bees chose the flower in the FAI position of the S+, and not the flower that would be chosen using strictly memory for a flight vector. Together, these experiments show that to locate the S+ bees did not rely on scent marks nor the positions of the S-, though the S- were prominent objects close to the goal. Also, bees selected environmental features to remember the position of the S+ instead of relying upon a purely egocentric point of view. Similarities with honeybees and vertebrates are discussed, as well as possible encoding mechanisms.
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Cheng, K., & Wignall, A. E. (2006). Honeybees (Apis mellifera) holding on to memories: response competition causes retroactive interference effects. Anim. Cogn., 9(2), 141–150.
Abstract: Five experiments on honeybees examined how the learning of a second task interferes with what was previously learned. Free flying bees were tested for landmark-based memory in variations on a paradigm of retroactive interference. Bees first learned Task 1, were tested on Task 1 (Test 1), then learned Task 2, and were tested again on Task 1 (Test 2). A 60-min delay (waiting in a box) before Test 2 caused no performance decrements. If the two tasks had conflicting response requirements, (e.g., target right of a green landmark in Task 1 and left of a blue landmark in Task 2), then a strong decrement on Test 2 was found (retroactive interference effect). When response competition was minimised during training or testing, however, the decrement on Test 2 was small or nonexistent. The results implicate response competition as a major contributor to the retroactive interference effect. The honeybee seems to hold on to memories; new memories do not wipe out old ones.
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