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Hauber, M. E., & Sherman, P. W. (2003). Designing and interpreting experimental tests of self-referent phenotype matching. Anim. Cogn., 6(1), 69–71.
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Potì, P. (2000). Aspects of spatial cognition in capuchins (Cebus apella): frames of reference and scale of space. Anim. Cogn., 3(2), 69–77.
Abstract: Frames of reference (i.e. sets of loci defining spatial locations) determine animals' performances in object search tasks. Reference frames are used at different scales. Although much behavioural research has been conducted on search strategies in many animal species, relatively little has been done on nonhuman primates. The two experiments reported here focused on the relative strength and the level of functioning of different reference frames at the small-scale level in four capuchins (Cebus apella). Two identical boxes and a landmark were placed on a round platform that could be rotated. A reward was hidden in subject's view under one box, and then a sash-screen was lowered to hide the rotation of the platform; the sash-screen was then lifted and the subject allowed to search for the reward. In experiment 1 the rewarded box was always the closer to the landmark, in experiment 2 it could be either the box closer to or the box farther from the landmark. Capuchins were successful after invisible rotations in experiment 1, but they failed after invisible rotations in experiment 2. Two possible explanations are proposed: (1) capuchins relied heavily on the left-right body-axis as a frame, and they could only substitute it with a simple association between the rewarded position and the landmark; or (2) capuchins failed because they chose external cues in the room, therefore on a inappropriate scale. The latter explanation allows two further inferences: (a) the capuchins' choice was indirectly related to their body-axes; and (b) the capuchins revealed a cognitive asymmetry between small-scale and large-scale spaces, thus differing from humans.
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Webster, S., & Fiorito, G. (2001). Socially guided behaviour in non-insect invertebrates. Anim. Cogn., 4(2), 69–79.
Abstract: A review of the past 50 years of literature on socially guided behaviour addresses two questions: (1) whether socially guided behaviour, which has traditionally been considered characteristic of vertebrates, is also found among non-insect invertebrates, and (2) to see whether our classification of socially guided behaviours in invertebrates matches, and thereby supports, A. Whiten and R. Ham's classification of vertebrate behaviours into two broad categories, social learning and social influence. We systematically reviewed the literature on socially guided behaviour in non-insect invertebrates to determine if social behaviours exist. Once this was established, we characterised our findings using 13 behavioural phenomena that are considered to be descriptive of socially guided behaviour. Using a multivariate technique, we then analysed the data to determine if our characterisation scheme produced a similar distribution to that presented by A. Whiten and R. Ham. Our results indicate that socially guided behaviours are present in invertebrates, and invertebrates can be placed into the previously established framework on vertebrate social behaviour. Further, our analysis reveals a prominent separation between representations of the social influence and social learning categories, thereby supporting the previously published framework on socially guided behaviour.
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Ward, C., & Smuts, B. B. (2007). Quantity-based judgments in the domestic dog (Canis lupus familiaris). Anim. Cogn., 10(1), 71–80.
Abstract: We examined the ability of domestic dogs to choose the larger versus smaller quantity of food in two experiments. In experiment 1, we investigated the ability of 29 dogs (results from 18 dogs were used in the data analysis) to discriminate between two quantities of food presented in eight different combinations. Choices were simultaneously presented and visually available at the time of choice. Overall, subjects chose the larger quantity more often than the smaller quantity, but they found numerically close comparisons more difficult. In experiment 2, we tested two dogs from experiment 1 under three conditions. In condition 1, we used similar methods from experiment 1 and tested the dogs multiple times on the eight combinations from experiment 1 plus one additional combination. In conditions 2 and 3, the food was visually unavailable to the subjects at the time of choice, but in condition 2, food choices were viewed simultaneously before being made visually unavailable, and in condition 3, they were viewed successively. In these last two conditions, and especially in condition 3, the dogs had to keep track of quantities mentally in order to choose optimally. Subjects still chose the larger quantity more often than the smaller quantity when the food was not simultaneously visible at the time of choice. Olfactory cues and inadvertent cuing by the experimenter were excluded as mechanisms for choosing larger quantities. The results suggest that, like apes tested on similar tasks, some dogs can form internal representations and make mental comparisons of quantity.
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Vlasak, A. N. (2006). Global and local spatial landmarks: their role during foraging by Columbian ground squirrels (Spermophilus columbianus). Anim. Cogn., 9(1), 71–80.
Abstract: Locating food and refuge is essential for an animal's survival. However, little is known how mammals navigate under natural conditions and cope with given environmental constraints. In a series of six experiments, I investigated landmark-based navigation in free-ranging Columbian ground squirrels (Spermophilus columbianus). Squirrels were trained individually to find a baited platform within an array of nine identical platforms and artificial landmarks set up on their territories. After animals learned the location of the food platform in the array, the position of the latter with respect to local artificial, local natural, and global landmarks was manipulated, and the animal's ability to find the food platform was tested. When only positions of local artificial landmarks were changed, squirrels located food with high accuracy. When the location of the array relative to global landmarks was altered, food-finding accuracy decreased but remained significant. In the absence of known global landmarks, the presence of a familiar route and natural local landmarks resulted in significant but not highly accurate performance. Squirrels likely relied on multiple types of cues when orienting towards a food platform. Local landmarks were used only as a secondary mechanism of navigation, and were not attended to when a familiar route and known global landmarks were present. This study provided insights into landmark use by a wild mammal in a natural situation, and it demonstrated that an array of platforms can be employed to investigate landmark-based navigation under such conditions.
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Chappell, J., & Kacelnik, A. (2002). Tool selectivity in a non-primate, the New Caledonian crow (Corvus moneduloides). Anim. Cogn., 5(2), 71–78.
Abstract: We present an experiment showing that New Caledonian crows are able to choose tools of the appropriate size for a novel task, without trial-and-error learning. This species is almost unique amongst all animal species (together with a few primates) in the degree of use and manufacture of polymorphic tools in the wild. However, until now, the flexibility of their tool use has not been tested. Flexibility, including the ability to select an appropriate tool for a task, is considered to be a hallmark of complex cognitive adaptations for tool use. In experiment 1, we tested the ability of two captive birds (one male, one female), to select a stick (from a range of lengths provided) matching the distance to food placed in a horizontal transparent pipe. Both birds chose tools matching the distance to their target significantly more often than would be expected by chance. In experiment 2, we used a similar task, but with the tools placed out of sight of the food pipe, such that the birds had to remember the distance of the food before selecting a tool. The task was completed only by the male, who chose a tool of sufficient length significantly more often than chance but did not show a preference for a matching length.
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Shuster, G., & Sherman, P. W. (1998). Tool use by naked mole-rats. Anim. Cogn., 1(1), 71–74.
Abstract: Naked mole-rats (Heterocephalus glaber, Rodentia: Bathyergidae) excavate extensive subterranean burrows with their procumbent incisors. Captive individuals often place a wood shaving or tuber husk behind their incisor teeth and in front of their lips and molar teeth while gnawing on substrates that yield fine particulate debris. This oral barrier may prevent choking or aspiration of foreign material. Consistent use of tools has rarely been reported in rodents.
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Mateo, J. M., & Johnston, R. E. (2003). Kin recognition by self-referent phenotype matching: weighing the evidence. Anim. Cogn., 6(1), 73–76.
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Pongrácz, P., Vida, V., Bánhegyi, P., & Miklósi, Á. (2008). How does dominance rank status affect individual and social learning performance in the dog (Canis familiaris)? Anim. Cogn., 11, 75–82.
Abstract: Dogs can learn effectively to detour around a V-shaped fence after observing a demonstration from either an unfamiliar human or dog demonstrator. We found earlier that there is substantial individual variation between the dogs' performance, even when using the same experimental conditions. Here, we investigate if the subjects' relative dominance rank with other dogs had an effect on their social learning performance. On the basis of the owners' answers to a questionnaire, subjects from multi-dog homes were sorted into groups of dominant and subordinate dogs. In Experiment 1, dominant and subordinate dogs were tested without demonstration and we did not find any difference between the groups-they had similarly low detour performances on their own. In Experiment 2 and 3, dogs from single dog and multi-dog households were tested in the detour task with demonstration by an unfamiliar dog, or human, respectively. The results showed that social learning performance of the single dogs fell between the dominant and subordinate multi-dogs with both dog and human demonstration. Subordinate dogs displayed significantly better performance after having observed a dog demonstrator in comparison to dominant dogs. In contrast, the performance of dominant and subordinate dogs was almost similar, when they observed a human demonstrator. These results suggest that perceived dominance rank in its own group has a strong effect on social learning in dogs, but this effect seems to depend also on the demonstrator species. This finding reveals an intricate organization of the social structure in multi-dog households, which can contribute to individual differences existing among dogs.
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Treichler, F. R. (2005). Successive reversal of concurrent discriminations by macaques (Macaca mulatta): proactive interference effects. Anim. Cogn., 8(2), 75–83.
Abstract: Rhesus monkeys received concurrent within-session training on eight, two-choice object pairs and then underwent successive reversals of these problems. Initially, reversals required about six times more training than acquisition with no improvement over seven successive reversals. Surprisingly, performance on these eight problems was unimpaired if they were embedded in different eight-problem tasks, thereby indicating a release from proactive interference. When the original eight problems again underwent successive reversal, no improvement was seen over seven reversals, although there was significantly less error-per-reversal than in the initial test. Subsequently, monkeys appeared to be developing a learning set for successive reversal because performance on successive reversal of eight novel problems was not different from that seen with the old familiar task. Set acquisition was confirmed when proficient reversal was eventually achieved on both old and new concurrent tasks. Thus, “concurrent reversal set” did develop, but it required arduous training to overcome proactive interference effects on memory. The ubiquitous influence of measurement context on organization of monkey memory was noted.
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