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Cynx, J., Hulse, S. H., & Polyzois, S. (1986). A psychophysical measure of pitch discrimination loss resulting from a frequency range constraint in European starlings (Sturnus vulgaris). J Exp Psychol Anim Behav Process, 12(4), 394–402.
Abstract: Earlier research (Hulse & Cynx, 1985) revealed that a number of species of songbirds acquired a pitch discrimination between rising and falling sequences in an arbitrarily defined training range of frequencies, but then failed to generalize the discrimination to new frequency ranges--a frequency range constraint. The two experiments here provide a psychophysical estimate of how pitch discrimination deteriorated in one species as sequences were stepped out from the training range. The gradient showing loss of discrimination was much sharper than would have been anticipated by stimulus generalization or the training procedures, and appeared unaffected by the removal of rising and falling frequency information. The frequency range constraint and its psychophysical properties have implications both for the analysis of birdsong and the study of animal cognition.
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Clement, T. S., & Zentall, T. R. (2003). Choice based on exclusion in pigeons. Psychon Bull Rev, 10(4), 959–964.
Abstract: When humans acquire a conditional discrimination and are given a novel-sample-comparison choice, they often reject a comparison known to be associated with a different sample and choose the alternative comparison by default (or by exclusion). In Experiment 1, we found that if, following matching training, we replaced both of the samples, acquisition took five times longer than if we replaced only one of the samples. Apparently, the opportunity to reject one of the comparisons facilitated the association of the other sample with the remaining comparison. In Experiment 2, we first trained pigeons to treat two samples differently (to associate Sample A with Comparison 1 and Sample B with Comparison 2) and then trained them to associate one of those samples with a new comparison (e.g., Sample A with Comparison 3) and to associate a novel sample (Sample C) with a different, new comparison (Comparison 4). When Sample B then replaced Sample C, the pigeons showed a significant tendency to choose Comparison 4 over Comparison 3. Thus, when given the opportunity, pigeons will choose by exclusion.
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Zentall, T. R., Clement, T. S., & Weaver, J. E. (2003). Symmetry training in pigeons can produce functional equivalences. Psychon Bull Rev, 10(2), 387–391.
Abstract: Functional stimulus equivalence has been demonstrated using a transfer of training design with matching-to-sample training in which two sample stimuli are associated with the same comparison stimulus (A-B, C-B; many-to-one matching). Equivalence is shown by training a new association (A-D) and demonstrating the presence of an emergent relation (C-D). In the present experiment, we show that symmetry training, in which a bidirectional association is trained between two stimuli (A-B, B-A, using successive stimulus presentations followed by reinforcement), can also produce functional equivalence using a transfer of training design (i.e., train B-C, test A-C). The results suggest that training pigeons in the substitutability of two stimuli may be sufficient to produce functional stimulus equivalence between them. The results also have implications for the development of an emergent transitive relation, because training on A-B and B-C relations results in the emergence of an untrained A-C relation, if B-A training also is provided.
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Sole, L. M., Shettleworth, S. J., & Bennett, P. J. (2003). Uncertainty in pigeons. Psychon Bull Rev, 10(3), 738–745.
Abstract: Pigeons classified a display of illuminated pixels on a touchscreen as sparse or dense. Correct responses were reinforced with six food pellets; incorrect responses were unreinforced. On some trials an uncertain response option was available. Pecking it was always reinforced with an intermediate number of pellets. Like monkeys and people in related experiments, the birds chose the uncertain response most often when the stimulus presented was difficult to classify correctly, but in other respects their behavior was not functionally similar to human behavior based on conscious uncertainty or to the behavior of monkeys in comparable experiments. Our data were well described by a signal detection model that assumed that the birds were maximizing perceived reward in a consistent way across all the experimental conditions.
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Zentall, T. R. (2006). Imitation: definitions, evidence, and mechanisms. Anim. Cogn., 9(4), 335–353.
Abstract: Imitation can be defined as the copying of behavior. To a biologist, interest in imitation is focused on its adaptive value for the survival of the organism, but to a psychologist, the mechanisms responsible for imitation are the most interesting. For psychologists, the most important cases of imitation are those that involve demonstrated behavior that the imitator cannot see when it performs the behavior (e.g., scratching one's head). Such examples of imitation are sometimes referred to as opaque imitation because they are difficult to account for without positing cognitive mechanisms, such as perspective taking, that most animals have not been acknowledged to have. The present review first identifies various forms of social influence and social learning that do not qualify as opaque imitation, including species-typical mechanisms (e.g., mimicry and contagion), motivational mechanisms (e.g., social facilitation, incentive motivation, transfer of fear), attentional mechanisms (e.g., local enhancement, stimulus enhancement), imprinting, following, observational conditioning, and learning how the environment works (affordance learning). It then presents evidence for different forms of opaque imitation in animals, and identifies characteristics of human imitation that have been proposed to distinguish it from animal imitation. Finally, it examines the role played in opaque imitation by demonstrator reinforcement and observer motivation. Although accounts of imitation have been proposed that vary in their level of analysis from neural to cognitive, at present no theory of imitation appears to be adequate to account for the varied results that have been found.
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Benard, J., Stach, S., & Giurfa, M. (2006). Categorization of visual stimuli in the honeybee Apis mellifera. Anim. Cogn., 9(4), 257–270.
Abstract: Categorization refers to the classification of perceptual input into defined functional groups. We present and discuss evidence suggesting that stimulus categorization can also be found in an invertebrate, the honeybee Apis mellifera, thus underlining the generality across species of this cognitive process. Honeybees show positive transfer of appropriate responding from a trained to a novel set of visual stimuli. Such a transfer was demonstrated for specific isolated features such as symmetry or orientation, but also for assemblies (layouts) of features. Although transfer from training to novel stimuli can be achieved by stimulus generalization of the training stimuli, most of these transfer tests involved clearly distinguishable stimuli for which generalization would be reduced. Though in most cases specific experimental controls such as stimulus balance and discriminability are still required, it seems appropriate to characterize the performance of honeybees as reflecting categorization. Further experiments should address the issue of which categorization theory accounts better for the visual performances of honeybees.
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Sousa, C., Okamoto, S., & Matsuzawa, T. (2003). Behavioural development in a matching-to-sample task and token use by an infant chimpanzee reared by his mother. Anim. Cogn., 6(4), 259–267.
Abstract: We investigated the behavioural and cognitive development of a captive male infant chimpanzee, Ayumu, raised by his mother, Ai. Here we report Ayumu's achievements up to the age of 2 years and 3 months, in the context of complex computer-controlled tasks. From soon after birth, Ayumu had been present during an experiment performed by his mother. The task consisted of two phases, a matching-to-sample task in which she received token rewards, and the insertion of these tokens into a vending machine to obtain food rewards. Ayumu himself received no reward or encouragement from humans for any of the actions he exhibited during the experiment. At the age of 9 months and 3 weeks, Ayumu performed his first matching-to-sample trial. At around 1 year and 3 months, he began to perform them consistently. Also during this period, he frequently stole food rewards from his mother. At 2 years and 3 months, Ayumu succeeded for the first time in inserting a token into the vending machine. Once he had succeeded in using a token, he performed both phases of the task in sequence 20 times consecutively. The infant's behaviour was not shaped by food rewards but by a strong motivation to copy his mother's behaviour. Our observations of Ayumu thus mirror the learning processes shown by wild chimpanzees.
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Kuroshima, H., Fujita, K., Adachi, I., Iwata, K., & Fuyuki, A. (2003). A Capuchin monkey (Cebus apella) recognizes when people do and do not know the location of food. Anim. Cogn., 6(4), 283–291.
Abstract: In a previous study, Kuroshima and colleagues demonstrated that capuchin monkeys (Cebus apella) learned to discriminate between a “knower” who inspected a box for food, and a “guesser” who did not. The aim of the present study was to specify whether the subjects learned a simple conditional discrimination or a causal relationship that seeing leads to knowing. In experiment 1, we introduced five types of novel containers to two subjects. Each container was of different shape and color. The subjects gradually learned to reach toward the container the knower suggested. In experiment 2, we diversified the behavior of the knower and the guesser. In experiment 3, in order to eliminate the possibility of discrimination based on differences in the magnitude and the complexity of two trainers, we equated their behaviors. One subject adapted to the novel behaviors of the knower and the guesser, successfully discriminating the two trainers. Thus this monkey clearly learned to use the inspecting action of the knower and the non-inspecting action of the guesser as a discriminative cue to recognize the baited container. This result suggests that one capuchin monkey learned to recognize the relationship between seeing and knowing.
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