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Cheney DL, & Seyfarth RM. (1992). Characterizing the mind of another species. Behav. Brain Sci., 15, 172.
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Lin AC, Bard KA, & Anderson JR. (1992). Development of self-recognition and self-conscious emotions. Child Dev., 106, 120.
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Povinelli DJ, & deBlois S. (1992). Young children's understanding of knowledge information in themselves and others. J. Comp. Psychol., 106, 228.
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Povinelli DJ, Nelson KE, & Boysen ST. (1992). Comprehension of role reversal in chimpanzees: evidence of empathy? Anim. Behav., 43, 633.
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Rubenstein, D. I., & Hack, M. A. (1992). Horse signals: The sounds and scents of fury. Evol. Ecol., 6(3), 254–260.
Abstract: During contests animals typically exchange information about fighting ability. Among feral horses these signals involve olfactory or acoustical elements and each type can effectively terminate contests before physical contact becomes necessary. Dung transplant experiments show that for stallions, irrespective of rank, olfactory signals such as dung sniffing encode information about familiarity suggesting that such signals can be used as signatures. As such they can provide indirect information about fighting ability as long as opponents associate identity with past performance. Play-back experiments, however, show that vocalizations, such as squeals, directly provide information about status regardless of stallion familiarity. Sonographs reveal that squeals of dominants are longer than those of subordinates and that only those of dominants have at their onset high-frequency components.
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Anderson, J. R., Fornasieri, I., Ludes, E., & Roeder, J. - J. (1992). Social processes and innovative behaviour in changing groups of lemur fulvus. Behav. Process., 27(2), 101–112.
Abstract: A group of brown lemurs was presented with one or two baited food-boxes requiring a specific type of motor response in order to be opened. Subsequently, four groups containing different combinations of experienced individuals from the original group and naive individuals were tested. Solutions to the problem and access to the food were recorded and considered in relation to social factors. In the original group, two adult males learned to open the boxes, with one male increasingly preventing the other from approaching. In the second group, with the subordinate male and certain females removed, the dominant male tolerated successful performances by a juvenile female. Group 3 consisted of three passive female participants from the original group and a naive female; one of the three original females now became the sole box-opener. The introduction of the subordinate male from the original group into the all-female group led to a sharing of box-opening by this subject and the skilled female. In the final group, intense aggression toward the skilled female by a new, naive adult male resulted in two previously passive females succeeding on some occasions. In lemurs, at least some `scroungers' appear able to learn to perform a new act when the social context permits.
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Keiper, R., & Receveur, H. (1992). Social interactions of free-ranging Przewalski horses in semi-reserves in the Netherlands. Appl. Anim. Behav. Sci., 33(4), 303–318.
Abstract: Social interactions were recorded in two bands of free-ranging Przewalski horses living on large (greater than 30 ha) pastures in the Netherlands. The average number of aggressive interactions per hour was 8.86 at Lelystad and 10.36 at Noorderheide. The most common aggressive interactions were lower intensity, lower cost displacements (17.2% of all aggressive acts at Lelystad, 13.2% at Noorderheide), threats to bite (42.3% and 40.7%, respectively) and threats to kick (15.4% and 23.9%, respectively). Analysis of aggression revealed that a clear, linear dominance hierarchy was present in each band. For each band there was a positive and highly significant correlation between the age of a horse and its rank in the hierarchy. In each band, the stallion was not the highest ranked horse. Non-agonistic behaviors exceeded the number of agonistic interactions (1253 vs. 558 for Lelystad; 1257 vs. 995 at Noorderheide). There was a negative correlation between the rank of a horse in the dominance hierarchy and the number of non-agonistic behaviors displayed. The group displaying the highest number of non-agonistic interactions were foals (48.9% of total non-agonistic behaviors at Lelystad; 51.1% at Noorderheide). The non-agonistic/agonistic ratio was greater than 1 for yearlings and the band stallion, as was also the case for foals, but was less than 1 for males.
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Timney, B., & Keil, K. (1992). Visual acuity in the horse. Vis. Res., 32(12), 2289–2293.
Abstract: We assessed the ease with which horses could learn visual discriminations and measured their resolution acuity. We trained three horses to press their noses against one of two large wooden panels to receive a small food reward. Following training on a series of two-choice discrimination tasks, resolution acuity was measured. Although there was some variability between animals, the best acuity obtained was 23.3 c deg-1. Within the margin of error imposed by limited anatomical data, the obtained values are consistent with predictions based on retinal ganglion cell density estimates and posterior nodal distance/axial length ratios. They suggest that the resolution acuity of the horse is limited by ganglion cell density in the temporal portion of the narrow visual streak.
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Kabuga, J. D. (1992). Social relationships in N'dama cattle during supplementary feeding. Appl. Anim. Behav. Sci., 34(4), 285–290.
Abstract: Social relationships of 30 N'dama cows during supplementary feeding, post-grazing, were studied over a period of 1.5 years. Dominance ranks determined during idling and feeding periods were strongly correlated (Spearman's rank correlation (rs = 0.964, P < 0.01). The number of animals dominated by a cow during feeding was strongly (P < 0.01) related to liveweight (r = 0.822) and age (r = 0.755). Low status cows ate less frequently than medium and high status animals, while middle ranking cows were ejected more frequently from the feed trough than other dominance groups. Animals had preferences in the use of feed troughs, with social rank being the dominant factor determining the location of feed trough space used. Cows of similar status were generally preferred feeding and movement neighbours and antagonists. However, the dominance rank of an animal and its preferred neighbour during idling were not significantly correlated (rs = 0.220, P > 0.05). Voluntary leadership ranks into and out of the pen were, respectively, related closely (P < 0.01) to feeding dominance ranks (rs = 0.661, 0.640) and idling dominance ranks (rs = 0.621, 0.669).
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Brunner, D., Kacelnik, A., & Gibbon, J. (1992). Optimal foraging and timing processes in the starling, Sturnus vulgaris: effect of inter-capture interval. Anim. Behav., 44(4), 597–613.
Abstract: Laboratory experiments with starlings, Sturnus vulgaris, were conducted to investigate the interaction between timing and cost-benefit considerations. The design simulated an environment in which food was distributed in patches. Patches contained a random number of food items (N=0-4) separated by a fixed inter-capture interval or fixed interval. All patches ended with sudden depletion. The time elapsed since the last prey capture was the only way to detect the depletion of the patch. Once the patch was depleted a new patch could be reached by travelling between two perches. Three measures of timing were taken: (1) rate of working for food as function of `waiting' time in a patch, (2) the time of the last response in a patch or `giving-in' time, and (3) the time at which travel was initiated or `moving-on' time. The fixed interval that characterized patches was varied between conditions. The mean time of the peak in working rate was consistently centred around the fixed interval, while the other two measures of timing kept a roughly linear relation to the fixed interval, with slope greater than one. In accordance with Scalar Expectancy Theory, variability in the three forms of timing was proportional to the magnitude of the fixed interval. The birds seemed to take account of this increase in variability as shown by the mean value of their giving-up criterion. These results imply that information-processing constraints are important for modelling behavioural optimality.
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