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Kaplan, G., & Rogers, L. J. (2002). Patterns of Gazing in Orangutans (Pongo pygmaeus). Int. J. Primatol., 23(3), 501–526.
Abstract: Eyes play an important role in communication amongst humans and animals. However, relatively little is known about specific differences in eye morphology amongst primates and how these features might be associated with social structure and direction of gaze. We present a detailed study of gazing and eye morphology-exposed sclera and surrounding features in orangutans. We measured gazing in rehabilitating orangutans in two contexts: interspecific viewing of the experimenter (with video camera) and intraspecific gazing (between subjects). Our findings show that direct staring is avoided and social looking is limited to certain age/social categories: juveniles engage in more looking at other orangutans than do adults or infants. While orangutans use eye movements in social communication, they avoid the more prolonged mutual gaze that is characteristic of humans, and also apparent in chimpanzees and gorillas. Detailed frame-by-frame analysis of videotapes from field and zoo studies of orangutans revealed that they pay visual attention to both human observers and conspecifics by glancing sideways, with the head turned at an angle away from the subject being observed. Mutual gaze was extremely rare, and we have observed only two incidences of gaze following. Orangutans in captivity appear to use a more restricted pattern of gazes compared to free-living, rehabilitating ones, possibly suggesting the presence of a pathological condition (such as depression) in the captive subjects. Our findings have implications for further investigations of social communication and cognition in orangutans.
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Crowley, P. H., Provencher, L., Sloane, S., Dugatkin, L. A., Spohn, B., Rogers, L., et al. (1996). Evolving cooperation: the role of individual recognition. Biosystems, 37(1-2), 49–66.
Abstract: To evaluate the role of individual recognition in the evolution of cooperation, we formulated and analyzed a genetic algorithm model (EvCo) for playing the Iterated Prisoner's Dilemma (IPD) game. Strategies compete against each other during each generation, and successful strategies contribute more of their attributes to the next generation. Each strategy is encoded on a `chromosome' that plays the IPD, responding to the sequences of most recent responses by the interacting individuals (chromosomes). The analysis reported in this paper considered different memory capabilities (one to five previous interactions), pairing continuities (pairs of individuals remain together for about one, two, five, or 1000 consecutive interactions), and types of individual recognition (recognition capability was maximal, nil, or allowed to evolve between these limits). Analysis of the results focused on the frequency of mutual cooperation in pairwise interactions (a good indicator of overall success in the IPD) and on the extent to which previous responses by the focal individual and its partner were associated with the partner's identity (individual recognition). Results indicated that a fixed, substantial amount of individual recognition could maintain high levels of mutual cooperation even at low pairing continuities, and a significant but limited capability for individual recognition evolved under selection. Recognition generally increased mutual cooperation more when the recent responses of individuals other than the current partner were ignored. Titrating recognition memory under selection using a fitness cost suggested that memory of the partner's previous responses was more valuable than memory of the focal's previous responses. The dynamics produced to date by EvCo are a step toward understanding the evolution of social networks, for which additional benefits associated with group interactions must be incorporated.
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McGreevy, P. D., & Rogers, L. J. (2005). Motor and sensory laterality in thoroughbred horses. Appl. Anim. Behav. Sci., 92(4), 337–352.
Abstract: We investigated lateralisation in horses because it is likely to be important in training and athletic performance. Thoroughbred horses (n = 106) were observed every 60 s for 2 h, when they were at pasture, and the position of the forelimbs in relation to one another was recorded. There was a population bias skewed to standing with the left forelimb advanced over the right (i.e. directional lateralisation). Using the first 50 observations, the distribution of preferences was 43 significantly left, 10 significantly right with 53 being non-significant (i.e. ambidextextrous). The strength of motor bias increased with age, suggesting maturation or an influence of training. The horses were also presented with an olfactory stimulus (stallion faeces) to score the tendency to use one nostril rather than the other. A significant preference to use the right nostril first was shown in horses under 4 years of age (n = 61) but not in older horses. Of the 157 horses tested for nostril bias, 76 had been assessed for motor bias and so were used for analysis of the relationship between laterality in the two modalities. There was no significant relationship between direction of foreleg motor bias and first nostril used, total number of inhalations or laterality index of nostril use. The absence of a correlation between laterality of nostril use and motor bias indicates that lateralisation of the equine brain occurs on at least two levels of neural organisation--sensory and motor--a finding that is consistent with other examples of lateralisation in species that have been examined in more detail.
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Rogers, L. J. (2002). Advantages and disadvantages of lateralization. In L. J. Rogers, & R. Andrew (Eds.), (pp. 126–153). New York: Cambridge University Press.
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Rogers, L. J. (2002). Evolution of Side Biases: Motor versus Sensory Lateralization. In M. K. Mandal, M. B. Bulman-Fleming, & G. Tiwari (Eds.), Side Bias: A Neuropsychological Perspective (3-p. 40). Springer Netherlands.
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Siniscalchi, M., Quaranta, A., & Rogers, L. J. (2008). Hemispheric specialization in dogs for processing different acoustic stimuli. PloS ONE, 3, e3349.
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Rogers, L. (2020). Asymmetry of Motor Behavior and Sensory Perception: Which Comes First? Symmetrie, 12(5), 690.
Abstract: By examining the development of lateralization in the sensory and motor systems of the human fetus and chick embryo, this paper debates which lateralized functions develop first and what interactions may occur between the different sensory and motor systems during development. It also discusses some known influences of inputs from the environment on the development of lateralization, particularly the effects of light exposure on the development of visual and motor lateralization in chicks. The effects of light on the human fetus are related in this context. Using the chick embryo as a model to elucidate the genetic and environmental factors involved in development of lateralization, some understanding has been gained about how these lateralized functions emerge. At the same time, the value of carrying out much more research on the development of the various types of lateralization has become apparent.
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Robins, A., & Rogers, L. J. (2004). Lateralized prey-catching responses in the cane toad, Bufo marinus: analysis of complex visual stimuli. Anim. Behav., 68(4), 767–775.
Abstract: We tested the responses of Bufo marinus to prey stimuli of varying visual complexity that were moved around the toads in either a clockwise or anticlockwise direction at 1.7 revolutions/min. Predatory responses directed at prey resembling an insect were frequent when the model insect moved clockwise across the visual midline into the right visual hemifield. In contrast, the toads tended to ignore such stimuli when they moved anticlockwise across the midline into the left hemifield. No such lateralization was found when a rectangular strip moved along its longest axis was presented in a similar way. The toads also directed more responses towards the latter stimulus than towards the insect prey. Hence, the results suggest that lateralized predatory responses occur for considered decisions on whether or not to respond to complex insect-like stimuli, but not for decisions on comparatively simple stimuli. We discuss similarities between the lateralized feeding responses of B. marinus and those of avian species, as support for the hypothesis that lateralized brain function in tetrapods may have arisen from a common lateralized ancestor.
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Austin, N. P., & Rogers, L. J. (2012). Limb preferences and lateralization of aggression, reactivity and vigilance in feral horses, Equus caballus. Anim. Behav., 83(1), 239–247.
Abstract: Observational field studies were conducted on two remote populations of feral horses in Australia to determine whether lateralization is a characteristic of Equus caballus as a species or results from handling by humans. Group 1 had been feral for two to five generations and Group 2 for 10–20 generations. In both groups, left-side biases were present during agonistic interactions and in reactivity and vigilance. Therefore, as in other vertebrates, the right hemisphere appears to be specialized to control agonistic behaviour and responses to potential threats. The leftwards bias was stronger in measures of behaviour involving more aggression and reactivity. Preferences to place one forelimb in front of the other during grazing were also determined. No population bias of forelimb preference was found, suggesting that such limb preferences present in domestic horses may be entrained. Since stronger individual limb preferences were found in immature than in adult feral horses, limb preference may be modified by maturation or experience in the natural habitat. Stronger limb preference was associated significantly with elevated attention to the environment but only in younger feral horses. No sex differences in lateralization were found. The findings are evidence that horses show visual lateralization, as in other vertebrates, not dependent on handling by humans. Limb preference during grazing, by contrast, does appear to depend on experience.
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Siniscalchi, M., McFarlane, J. R., Kauter, K. G., Quaranta, A., & Rogers, L. J. (2013). Cortisol levels in hair reflect behavioural reactivity of dogs to acoustic stimuli. Research in Veterinary Science, 94(1), 49–54.
Abstract: Cortisol levels in hair samples were examined in fourteen domestic dogs and related to the dogs’ responses to different acoustic stimuli. Stimuli were playbacks of species-typical vocalizations recorded during three different situations (“disturbance”, “isolation” and “play” barks) and the sounds of a thunderstorm. Hair samples were collected at 9:00 h and 17:00 h two weeks after the behavioural tests. Results showed that behavioural reactivity to playback of the various stimuli correlates with cortisol levels in hair samples collected at 9:00 h, and the same was the case for the separate measures of behaviour (i.e. hiding, running away, seeking attention from the tester, panting and lowering of the body posture). Hence, levels of cortisol in hair appear to reflect the dog’s chronic state of emotional reactivity, or temperament.
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