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Diekamp, B., Prior, H., & Güntürkün, O. (1999). Functional lateralization, interhemispheric transfer and position bias in serial reversal learning in pigeons (Columba livia). Anim. Cogn., 2(4), 187–196.
Abstract: In the present study we investigated lateralization of color reversal learning in pigeons. After monocular acquisition of a simple color discrimination with either the left or right eye, birds were tested in a serial reversal procedure. While there was only a slight and non-significant difference in choice accuracy during original color discrimination, a stable superiority of birds using the right eye emerged in serial reversals. Both groups showed a characteristic 'learning-to-learn' effect, but right-eyed subjects improved faster and reached a lower asymptotic error rate. Subsequent testing for interocular transfer demonstrated a difference between pre- and post-shift choice accuracy in pigeons switching from right to left eye but not vice versa. This can be accounted for by differences in maximum performance using either the left or right eye along with an equally efficient but incomplete interocular transfer in both directions. Detailed analysis of the birds' response patterns during serial reversals revealed a preference for the right of two response keys in both groups. This bias was most pronounced at the beginning of a session. It decreased within sessions, but became more pronounced in late reversals, thus indicating a successful strategy for mastering the serial reversal task. Interocular transfer of response patterns revealed an unexpected asymmetry. Birds switching from right to left eye continued to prefer the right side, whereas pigeons shifting from left to right eye were now biased towards the left side. The results suggest that lateralized performance during reversal learning in pigeons rests on a complex interplay of learning about individual stimuli, stimulus dimensions, and lateralized response strategies.
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Á. Miklósi. (1999). The Evolution of Cognition. Anim. Cogn., 2(3), 179–180.
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Gould, J. L., Zabka, T. S., Malizia, R. W., Park, A., & Mukerji, J. (1999). Possible decision-making preadaptations in the molly Poecilia sphenops. Anim. Cogn., 2(2), 91–95.
Abstract: In many species females choose a mate from among several available males; in other species, the social system provides no apparent opportunity for making a decision among alternative suitors, and decision-making capacity is assumed to be minimal. The origins, bases, and logic of female mate choices are contentious questions with important cognitive implications. Female short-finned mollies, Poecilia sphenops, have never been observed to choose mates in the wild, where instead a male-contest social system prevails. Nevertheless they readily choose between models of males in the laboratory. Some of their decisions anticipate features found in males in more recently evolved species where the social system permits female choice. The willingness of females to choose traits in a species without such traits or evident need or opportunity for female choice in the wild is remarkable. These observations suggest that choice behavior can be latent in a species, and may direct or bias the development of behavioral preferences.
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Soler, M., & Soler, J. J. (1999). Innate versus learned recognition of conspecifics in great spotted cuckoos Clamator glandarius. Anim. Cogn., 2(2), 97–102.
Abstract: When birds raised by another species become adults, they (if they are non-brood-parasitic species) usually attempt to mate with birds of their foster species rather than with birds of their own species, a phenomenon called sexual imprinting. Avian brood parasites lay their eggs in nests of other species (the hosts) that rear the young, but the problem of sexual imprinting among brood parasites has generally been neglected, and brood parasites have been considered as an exception among birds. Here, we show, with data from field observations and field experiments, firstly, that adult great spotted cuckoos Clamator glandarius sometimes maintain contact with both older nestling and fledgling cuckoos. Adult cuckoos visited parasitized nests during the last days of the nestling period (5 observations) and, when parasitic chicks left the nest, adult cuckoos maintained contact with the young (14 observations). Adults and fledgling cuckoos communicated vocally (5 observations), and an adult great spotted cuckoo even fed a parasite fledgling in two cases. Secondly, when experimentally cross-fostered in nests of magpie Pica pica hosts outside the parasite breeding range (thus avoiding visual and acoustic communication with adult cuckoos), young cuckoos did not learn to recognize their own species when only one cuckoo chick was introduced per nest, but they learnt to recognize conspecifics when two cuckoos were reared together. This means that young great spotted cuckoos apparently must learn to recognize conspecifics, that is, recognition is not innate. Social interactions between adult brood parasites and young have also been reported in other brood parasites; thus, brood parasites are probably not an exception to the general phenomenon of imprinting, and young brood parasites may need to be imprinted on conspecifics, although more studies on other brood parasite species are needed to confirm this.
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Parr, L. A., Winslow, J. T., & Hopkins, W. D. (1999). Is the inversion effect in rhesus monkeys face-specific? Anim. Cogn., 2(3), 123–129.
Abstract: This study investigated the face inversion effect in rhesus monkeys (Macaca mulatta). Face stimuli consisted of ten black-and-white examples of unfamiliar rhesus monkey faces, brown capuchin faces, and human faces. Two non-face categories included ten examples of automobiles and abstract shapes. All stimuli were presented in a sequential matching-to-sample format using an automated joystick-testing paradigm. Subjects performed significantly better on upright than on inverted presentations of automobiles, rhesus monkey and capuchin faces, but not human faces or abstract shapes. These results are inconsistent with data from humans and chimpanzees that show the inversion effect only for categories of stimuli for which subjects have developed expertise. The inversion effect in rhesus monkeys does not appear to be face-specific, and should therefore not be used as a marker of specialized face processing in this species.
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Topál, J., & Csányi, V. (1999). Interactive learning in the paradise fish (Macropodus opercularis): an ethological interpretation of the second-order conditioning paradigm. Anim. Cogn., 2(4), 197–206.
Abstract: This study was aimed at the examination of 'mental construction' in paradise fish by interactive learning, which is suggested as an alternative hypothesis for backward or second-order conditioning. Avoidance of goldfish was established in paradise fish by presenting a harmless goldfish (a novel stimulus) after an aversive event (mild electric shocks) in the dark compartment of a shuttle tank. It was found that this avoidance depended on context pre-exposure. Experiment 1 was designed to study the effect of mild shocks on shuttling activity in a familiar context. Experiment 2 aimed at establishing fear-conditioning to the goldfish in a higher-order conditioning paradigm. In the course of training, unpaired stimuli were presented in the dark compartment of the shuttle tank in such a manner that the presentation of mild shocks (20 mA) preceded the encounter with a harmless fish (goldfish). Experiment 3 demonstrated the role of context pre-exposure in interactive learning. Results indicate that (1) while 60 mA shocks resulted in avoidance of the dark compartment, the 20 mA mild shocks affected exploratory behaviour; (2) after pre-exposure to the training environment, paradise fish avoided the dark compartment containing goldfish provided that subjects had previously encountered mild, explorative shocks there; (3) this conditioned fear, a 'mental construction' of a potential danger, was proved to be transferable to another context and was consequently aimed specifically at the goldfish, a living being, rather than the training context; (4) the pre-exposure to the shuttle tank was an important part of this training procedure, that is, only subjects habituated to the shuttle tank avoided the goldfish. Results are discussed in the framework of the Interactive Learning Hypothesis, which has been developed as an ethological approach to a higher-order conditioning paradigm.
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Wauters, A. M., Richard-Yris, M. - A., Richard, J. P., & Foraste M. (1999). Internal and external factors modulate food-calling in domestic hens. Anim. Cogn., 2(1), 1–10.
Abstract: Two series of experiments investigated factors affecting utterance of food calls in the domestic hen, Gallus domesticus. The first series of experiments tested the effect of food preference and the hen’s internal state on the utterance of food calls. Different food types were presented first singly and then in a choice test to 20 hens, first when hens were laying, and then when they were maternal. The second series of experiments tested the effect of hunger level on the utterance of food calls in laying hens, and maternal hens with or without chicks. These two series of experiments showed that laying hens and maternal hens showed a similar marked preference for certain types of food, but laying hens very rarely emitted food calls, in contrast to maternal hens. This shows the effect of the bird’s psychophysiological state on her tendency to emit food calls. The more a maternal hen preferred a food type, the more food calls she emitted. This was observed from the beginning of a test in single-food tests as well as in choice tests. Hunger level positively affected food-call production under certain feeding conditions in maternal hens, but not in laying hens. When maternal hens were tested in the absence of their chicks, utterance of food calls was more sustained than in the presence of chicks.
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Westergaard, G. C. (1999). Structural analysis of tool-use by tufted capuchins (Cebus apella) and chimpanzees (Pan troglodytes). Anim. Cogn., 2(3), 141–145.
Abstract: Using Matsuzawa's hierarchical system of classification, I compared tool-use patterns of tufted capuchins (Cebus apella) to those of chimpanzees (Pan troglodytes). The results indicated that wild C. apella exhibit fewer and less complex tool-use patterns than do captive C. apella and wild and captive P. troglodytes. Although most patterns of tool-use observed among P. troglodytes occur in captive C. apella, there are some notable exceptions, including tool-use in communicative contexts and the use ¶of three-tool combinations. I conclude that C. apella are unique among monkeys in their demonstrated propensities for higher-order combinatorial behavior and are likely capable of using symbolic combinations, although not at the level of complexity that has been demonstrated in ¶P. troglodytes.
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Wiltschko, W., Balda, R. P., Jahnel, M., & Wiltschko, R. (1999). Sun compass orientation in seed-caching corvids: its role in spatial memory. Anim. Cogn., 2(4), 215–221.
Abstract: The role of sun compass orientation in spatial memory of Clark's nutcrackers, Nucifraga columbiana, and pinyon jays, Gymnorhinus cyanocephalus, was studied in a series of cache recovery experiments. Birds were tested in an octagonal outdoor aviary with sand-filled cups inserted in the floor. For caching, only 12 such cups in a 90° sector were available, while for recovery 4-7 days later all 48 cups in the entire aviary were open. In control tests, the birds concentrated their search activity in the sector where they had cached. When their internal clock was shifted 6 h between caching and recovery, pinyon jays shifted their search activity to the 90° adjacent sector, as predicted if the sun compass was used. Clark's nutcrackers did not respond to the first clock-shift; however, they, too, shifted their search activity after a second clock-shift back to normal. This suggests that the sun compass is a component of spatial memory in both species. Clark's nutcrackers, however, seem to rely on their sun compass to a lesser degree than pinyon jays or the previously studied scrub jays. A comparison of the findings indicates that the role of the sun in spatial memory might reflect differences in habitat and ecology of the three corvid species.
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Theall, L. A., & Povinelli, D. J. (1999). Do chimpanzees tailor their gestural signals to fit the attentional states of others? Anim. Cogn., 2(4), 207–214.
Abstract: The use of vocalizations and tactile gestures by seven juvenile chimpanzees was experimentally investigated. The subjects interacted with an experimenter who typically handed them food rewards. In some trials, however, the experimenter waited 20 s before doing so. In these trials the experimenter's eyes were either open or closed, or the experimenter was either looking away from the subject or looking directly at him/her inquisitively with head movements. Although the chimpanzees produced at least one of the non-visual gestures mentioned (touching/tapping the experimenter or vocalizing) in 72% of all experimental trials, these actions and vocalizations were deployed without regard to the attentional state of their potential recipient, despite evidence that the subjects noticed the postures that defined the experimenter's attentional state. The results are discussed in the context of the distinction between the evolution of an understanding of seeing/attention as an internal mental state versus an understanding of behavioral postures alone.
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