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McGreevy, P. D. (2004).
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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.
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Nakagawa, S., & Waas, J. R. (2004). 'O sibling, where art thou?' – A review of avian sibling recognition with respect to the mammalian literature. Biological Reviews of the Cambridge Philosophical Society, 79(1), 101–119.
Abstract: Avian literature on sibling recognition is rare compared to that developed by mammalian researchers. We compare avian and mammalian research on sibling recognition to identify why avian work is rare, how approaches differ and what avian and mammalian researchers can learn from each other. Three factors: (1) biological differences between birds and mammals, (2) conceptual biases and (3) practical constraints, appear to influence our current understanding. Avian research focuses on colonial species because sibling recognition is considered adaptive where 'mixing potential' of dependent young is high; research on a wider range of species, breeding systems and ecological conditions is now needed. Studies of acoustic recognition cues dominate avian literature; other types of cues (e.g. visual, olfactory) deserve further attention. The effect of gender on avian sibling recognition has yet to be investigated; mammalian work shows that gender can have important influences. Most importantly, many researchers assume that birds recognise siblings through 'direct familiarisation' (commonly known as associative learning or familiarity); future experiments should also incorporate tests for 'indirect familiarisation' (commonly known as phenotype matching). If direct familiarisation proves crucial, avian research should investigate how periods of separation influence sibling discrimination. Mammalian researchers typically interpret sibling recognition in broad functional terms (nepotism, optimal outbreeding); some avian researchers more successfully identify specific and testable adaptive explanations, with greater relevance to natural contexts. We end by reporting exciting discoveries from recent studies of avian sibling recognition that inspire further interest in this topic.
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Brosnan, S. F., & de Waal, F. B. M. (2004). A concept of value during experimental exchange in brown capuchin monkeys, Cebus apella. Folia Primatol (Basel), 75(5), 317–330.
Abstract: We evaluated the response of brown capuchin monkeys to two differentially valued tokens in an experimental exchange situation akin to a simple barter. Monkeys were given a series of three tests to evaluate their ability to associate tokens with food, then their responses were examined in a barter situation in which tokens were either limited or unlimited. Capuchins did not perform barter in the typical sense, returning the tokens which were associated with the reward. However, females, but not males, showed a different response, preferring the higher-value token. This may indicate that they learned to prefer one token over the other rather than to associate the tokens with their specific rewards. This sex difference parallels previous findings of greater reciprocity in female brown capuchins than in males.
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Bering, J. M. (2004). A critical review of the “enculturation hypothesis”: the effects of human rearing on great ape social cognition. Anim. Cogn., 7(4), 201–212.
Abstract: Numerous investigators have argued that early ontogenetic immersion in sociocultural environments facilitates cognitive developmental change in human-reared great apes more characteristic of Homo sapiens than of their own species. Such revamping of core, species-typical psychological systems might be manifest, according to this argument, in the emergence of mental representational competencies, a set of social cognitive skills theoretically consigned to humans alone. Human-reared great apes' capacity to engage in “true imitation,” in which both the means and ends of demonstrated actions are reproduced with fairly high rates of fidelity, and laboratory great apes' failure to do so, has frequently been interpreted as reflecting an emergent understanding of intentionality in the former. Although this epigenetic model of the effects of enculturation on social cognitive systems may be well-founded and theoretically justified in the biological literature, alternative models stressing behavioral as opposed to representational change have been largely overlooked. Here I review some of the controversy surrounding enculturation in great apes, and present an alternative nonmentalistic version of the enculturation hypothesis that can also account for enhanced imitative performance on object-oriented problem-solving tasks in human-reared animals.
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Nakagawa, S. (2004). A farewell to Bonferroni: the problems of low statistical power and publication bias. Behav Ecol, 15.
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Nakagawa, S. (2004). A farewell to Bonferroni: the problems of low statistical power and publication bias. beheco, 15(6), 1044–1045.
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Brandt, K. (2004). A Language of Their Own: An Interactionist Approach to Human-Horse Communication. Society and Animals, 12(4), 299–316.
Abstract: This paper explores the process of human-horse communication using ethnographic data of in-depth interviews and participant observation. Guided by symbolic interactionism, the paper argues that humans and horses co-create a language system by way of the body to facilitate the creation of shared meaning. This research challenges the privileged status of verbal language and suggests that non-verbal communication and language systems of the body have their own unique complexities. This investigation of humanhorse communication offers new possibilities to understand the subjective and intersubjective world of non-verbal language using beings-human and nonhuman alike.
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McBride, S. D., Hemmings, A., & Robinson, K. (2004). A preliminary study on the effect of massage to reduce stress in the horse. Journal of Equine Veterinary Science, 24(2), 76–81.
Abstract: The use of massage (as a potential form of acupressure) has long been documented as a human relaxation aid. However, little scientific research has been carried out into its potential use as a form of stress reduction in the horse. This preliminary study investigated the effect of massage at six different sites (thoracic trapezius [withers], mid-brachiocephalicus, cervical ventral serrate and cervical trapezius [mid-neck], proximal gluteal fascia and proximal superficial gluteal [croup], proximal and mid-semitendinosus [second thigh], lateral triceps, proximal extensor carpi radialis and proximal common digital extensor [forearm], proximal brachiocephalicus, proximal splenius and ear [poll and ears) on stress-related behavioral and physiological (heart rate [HR]) measures in the horse. Ten riding school ponies/horses were massaged at each of the six sites (three preferred and three nonpreferred sites of allogrooming (mutual grooming between conspecifics) and changes in HR and behavior were recorded. The results indicated that during massage, all sites except the forearm resulted in a significant reduction in HR (P < .05) with massage at the withers, mid-neck, and croup having the greatest effect (preferred sites of allogrooming). Massage at preferred sites of allogrooming also elicited significantly more (P < .05) positive behavioral responses compared with the three nonpreferred sites. The practical implications of this study are discussed.
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Pinchbeck, G. L., Clegg, P. D., Proudman, C. J., Morgan, K. L., & French, N. P. (2004). A prospective cohort study to investigate risk factors for horse falls in UK hurdle and steeplechase racing. Equine Vet J, 36(7), 595–601.
Abstract: REASONS FOR PERFORMING STUDY: Equine fatalities during racing continue to be a major welfare concern and falls at fences are responsible for a proportion of all equine fatalities recorded on racecourses. OBJECTIVES: To identify and quantify risk factors for horse falls in National Hunt (NH) racing and to report the frequency of falling and falling-associated fatalities. METHODS: A prospective cohort study was conducted on 2879 horse starts in hurdle and steeplechase races on 6 UK racecourses. Any horse that suffered a fall at a steeplechase or hurdle fence during the race was defined as a case. Data were obtained by interview and observations in the parade ring and from commercial databases. Multivariable logistic regression models, allowing for clustering at the level of the track, were used to identify the relationship between variables and the risk of falling. RESULTS: There were 124 falling cases (32 in hurdling and 92 in steeplechasing) identified. The injury risk of fallers was 8.9% and fatality risk 6.5%. Duration of journey to the racecourse, behaviour in the parade ring and weather at the time of the race were associated with falling in both hurdle and steeplechase racing. Age, amount of rainfall and going were also associated with falling in steeplechase racing. CONCLUSIONS: Falls at fences are significant contributors to equine fatalities during NH racing. Potentially modifiable risk factors identified were the condition of track surfaces and journey time to the racecourse. POTENTIAL RELEVANCE: It is hoped that information from this study may be used in future interventions to improve horse and jockey safety in racing. The study has also identified areas requiring further research, such as equine behaviour and its effect on racing performance, and the effect of light conditions on jumping ability.
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