|
|
Pepperberg, I. M. (2004). “Insightful” string-pulling in Grey parrots (Psittacus erithacus) is affected by vocal competence. Anim. Cogn., 7(4), 263–266.
Abstract: Four Grey parrots (Psittacus erithacus) were tested on their ability to obtain an item suspended from a string such that mutiple, repeated, coordinated beak-foot actions were required for success (e.g., Heinrich 1995). Those birds with little training in referential English requests (e.g. “I want X”) succeeded, whereas birds who could request the suspended item failed to obtain the object but engaged in repeated requesting.
|
|
|
|
Fortes, A. F., Merchant, H., & Georgopoulos, A. P. (2004). Comparative and categorical spatial judgments in the monkey: “high” and “low”. Anim. Cogn., 7(2), 101–108.
Abstract: Adult human subjects can classify the height of an object as belonging to either of the “high” or “low” categories by utilizing an abstract concept of midline that divides the vertical dimension into two halves. Children lack this abstract concept of midline, do not have a sense that these categories are directional opposites, and their categorical and comparative usages of high(er) or low(er) are restricted to the corresponding poles. We investigated the abilities of a rhesus monkey to perform categorical judgments in space. We were also interested in the presence of the congruity effect (a decrease in response time when the objects compared are closer to the category pole) in the monkey. The presence of this phenomenon in the monkey would allow us to relate the behavior of the animal to the two major competing hypotheses that have been suggested to explain the congruity effect in humans: the analog and semantic models. The monkey was trained in delayed match-to-sample tasks in which it had to categorize objects as belonging to either a high or low category. The monkey was able to generate an abstract notion of midline in a fashion similar to that of adult human subjects. The congruity effect was also present in the monkey. These findings, taken together with the notion that monkeys are not considered to think in propositional terms, may favor an analog comparison model in the monkey.
|
|
|
|
Goto, K., Wills, A. J., & Lea, S. E. G. (2004). Global-feature classification can be acquired more rapidly than local-feature classification in both humans and pigeons. Anim. Cogn., 7(2), 109–113.
Abstract: When humans process visual stimuli, global information often takes precedence over local information. In contrast, some recent studies have pointed to a local precedence effect in both pigeons and nonhuman primates. In the experiment reported here, we compared the speed of acquisition of two different categorizations of the same four geometric figures. One categorization was on the basis of a local feature, the other on the basis of a readily apparent global feature. For both humans and pigeons, the global-feature categorization was acquired more rapidly. This result reinforces the conclusion that local information does not always take precedence over global information in nonhuman animals.
|
|
|
|
Yamazaki, Y., Shinohara, N., & Watanabe, S. (2004). Visual discrimination of normal and drug induced behavior in quails (Coturnix coturnix japonica). Anim. Cogn., 7(2), 128–132.
Abstract: The ability to discriminate the physical states of others could be an adaptive behavior, especially for social animals. For example, the ability to discriminate illness behavior would be helpful for avoiding spoiled foods. We report on an experiment with Japanese quails testing whether these birds can discriminate the physical states of conspecifics. The quails were trained to discriminate between moving video images of quails injected with psychoactive drugs and those in a normal (not injected) condition. Methamphetamine (stimulant) or ketamine (anesthetic) were used to produce drug-induced behaviors in conspecifics. The former induced hyperactive behavior and the latter hypoactive behavior. The subject quails could learn the discrimination and showed generalization to novel images of the drug-induced behaviors. They did not, however, show discriminative behavior according to the type and dosage of the drugs. Thus, they categorized the behavior not on the basis of degree of activity, but on the basis of abnormality.
|
|
|
|
Hampton, R. R., Zivin, A., & Murray, E. A. (2004). Rhesus monkeys (Macaca mulatta) discriminate between knowing and not knowing and collect information as needed before acting. Anim. Cogn., 7(4), 239–246.
Abstract: Humans use memory awareness to determine whether relevant knowledge is available before acting, as when we determine whether we know a phone number before dialing. Such metacognition, or thinking about thinking, can improve selection of appropriate behavior. We investigated whether rhesus monkeys ( Macaca mulatta) are capable of a simple form of metacognitive access to the contents of short-term memory. Monkeys chose among four opaque tubes, one of which concealed food. The tube containing the reward varied randomly from trial to trial. On half the trials the monkeys observed the experimenter baiting the tube, whereas on the remaining trials their view of the baiting was blocked. On each trial, monkeys were allowed a single chance to select the tube containing the reward. During the choice period the monkeys had the opportunity to look down the length of each tube, to determine if it contained food. When they knew the location of the reward, most monkeys chose without looking. In contrast, when ignorant, monkeys often made the effort required to look, thereby learning the location of the reward before choosing. Looking improved accuracy on trials on which monkeys had not observed the baiting. The difference in looking behavior between trials on which the monkeys knew, and trials on which they were ignorant, suggests that rhesus monkeys discriminate between knowing and not knowing. This result extends similar observations made of children and apes to a species of Old World monkey, suggesting that the underlying cognitive capacities may be widely distributed among primates.
|
|
|
|
Jackson, R. R., & Li, D. (2004). One-encounter search-image formation by araneophagic spiders. Anim. Cogn., 7(4), 247–254.
Abstract: An experimental study of search-image use by araneophagic jumping spiders (i.e., salticid spiders that prey routinely on other spiders) supports five conclusions. First, araneophagic salticids have an innate predisposition to form search images for specific prey from their preferred prey category (spiders) rather than for prey from a non-preferred category (insects). Second, single encounters are sufficient for forming search images. Third, search images are based on selective attention specifically to optical cues. Fourth, there are trade-offs in attention during search-image use (i.e., forming a search image for one type of spider diminishes the araneophagic salticid's attention to other spiders). Fifth, the araneophagic salticid's adoption of search images is costly to the prey (i.e., when the araneophagic salticid adopts a search, the prey's prospects for surviving encounters with the araneophagic salticid are diminished). Cognitive and ecological implications of search-image use are discussed.
|
|
|
|
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.
|
|
|
|
Bovet, D., Vauclair, J., & Blaye, A. (2005). Categorization and abstraction abilities in 3-year-old children: a comparison with monkey data. Anim. Cogn., 8(1), 53–59.
Abstract: Three-year-old children were tested on three categorization tasks of increasing levels of abstraction (used with adult baboons in an earlier study): the first was a conceptual categorization task (food vs toys), the second a perceptual matching task (same vs different objects), and the third a relational matching task in which the children had to sort pairs according to whether or not the two items belonged to the same or different categories. The children were tested using two different procedures, the first a replication of the procedure used with the baboons (pulling one rope for a category or a relationship between two objects, and another rope for the other category or relationship), the second a task based upon children's prior experiences with sorting objects (putting in the same box objects belonging to the same category or a pair of objects exemplifying the same relation). The children were able to solve the first task (conceptual categorization) when tested with the sorting into boxes procedure, and the second task (perceptual matching) when tested with both procedures. The children were able to master the third task (relational matching) only when the rules were clearly explained to them, but not when they could only watch sorting examples. In fact, the relational matching task without explanation requires analogy abilities that do not seem to be fully developed at 3 years of age. The discrepancies in performances between children tested with the two procedures, with the task explained or not, and the discrepancies observed between children and baboons are discussed in relation to differences between species and/or problem-solving strategies.
|
|
|
|
O'Connell, S., & Dunbar, R. I. M. (2005). The perception of causality in chimpanzees (Pan spp.). Anim. Cogn., 8(1), 60–66.
Abstract: Chimpanzees (Pan spp.) were tested on a habituation/dishabituation paradigm that was originally developed to test for comprehension of causality in very young human infants. Three versions of the test were used: a food item being moved by a hand, a human pushing another human off a chair to obtain a food item, and a film clip of natural chimpanzee behaviour (capturing and eating a monkey). Chimpanzees exhibited similar results to those obtained with human infants, with significantly elevated levels of looking on the dishabituation trials. Since the level of response was significantly greater on natural/unnatural sequences than on unnatural/natural sequences, we conclude that the chimpanzees were not responding just to novelty but rather to events that infringed their sense of natural causation.
|
|
|
|
Osthaus, B., Lea, S. E. G., & Slater, A. M. (2005). Dogs (Canis lupus familiaris) fail to show understanding of means-end connections in a string-pulling task. Anim. Cogn., 8(1), 37–47.
Abstract: Domestic dogs (Canis lupus familiaris) were tested in four experiments for their understanding of means-end connections. In each of the experiments, the dogs attempted to retrieve a food treat that could be seen behind a barrier and which was connected, via string, to a within-reach wooden block. In the experiments, either one or two strings were present, but the treat was attached only to one string. Successful retrieval of the treat required the animals to pull the appropriate string (either by pawing or by grasping the wooden block in their jaws) until the treat emerged from under the barrier. The results showed that the dogs were successful if the treat was in a perpendicular line to the barrier, i.e. straight ahead, but not when the string was at an angle: in the latter condition, the typical response was a proximity error in that the dogs pawed or mouthed at a location closest in line to the treat. When two strings that crossed were present, the dogs tended to pull on the wrong string. The combined results from the experiments show that, although dogs can learn to pull on a string to obtain food, they do not spontaneously understand means-end connections involving strings.
|
|
