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Cain, K. E., Rich, M. S., Ainsworth, K., & Ketterson, E. D. (2011). Two Sides of the Same Coin? Consistency in Aggression to Conspecifics and Predators in a Female Songbird. Ethology, 117(9), 786–795.
Abstract: Different forms of aggression have traditionally been treated separately according to function or context (e.g., aggression towards a conspecific vs. a predator). However, recent work on individual consistency in behavior predicts that different forms of aggression may be correlated across contexts, suggesting a lack of independence. For nesting birds, aggression towards both conspecifics and nest predators can affect reproductive success, yet the relationship between these behaviors, especially in females, is not known. Here, we examine free-living female dark-eyed juncos (Junco hyemalis) and compare their aggressive responses towards three types of simulated intruders near the nest: a same-sex conspecific, an opposite-sex conspecific, and a nest predator. We also examine differences in the strength of response that might relate to the immediacy of the perceived threat the intruder poses for the female or her offspring. We found greater aggression directed towards a predator than a same-sex intruder and towards a same-sex than an opposite-sex intruder, consistent with a predator being a more immediate threat than a same-sex intruder, followed by an opposite-sex intruder. We also found positive relationships across individuals between responses to a same-sex intruder and a simulated predator, and between responses to a same-sex and an opposite-sex intruder, indicating that individual females are consistent in their relative level of aggression across contexts. If correlated behaviors are mediated by related mechanisms, then different forms of aggression may be expressions of the same behavioral tendency and constrained from evolving independently.
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Ramsden, S., Richardson, F. M., Josse, G., Thomas, M. S. C., Ellis, C., Shakeshaft, C., et al. (2011). Verbal and non-verbal intelligence changes in the teenage brain. Nature, advance online publication.
Abstract: Intelligence quotient (IQ) is a standardized measure of human intellectual capacity that takes into account a wide range of cognitive skills1. IQ is generally considered to be stable across the lifespan, with scores at one time point used to predict educational achievement and employment prospects in later years1. Neuroimaging allows us to test whether unexpected longitudinal fluctuations in measured IQ are related to brain development. Here we show that verbal and non-verbal IQ can rise or fall in the teenage years, with these changes in performance validated by their close correlation with changes in local brain structure. A combination of structural and functional imaging showed that verbal IQ changed with grey matter in a region that was activated by speech, whereas non-verbal IQ changed with grey matter in a region that was activated by finger movements. By using longitudinal assessments of the same individuals, we obviated the many sources of variation in brain structure that confound cross-sectional studies. This allowed us to dissociate neural markers for the two types of IQ and to show that general verbal and non-verbal abilities are closely linked to the sensorimotor skills involved in learning. More generally, our results emphasize the possibility that an individual’s intellectual capacity relative to their peers can decrease or increase in the teenage years. This would be encouraging to those whose intellectual potential may improve, and would be a warning that early achievers may not maintain their potential.
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Pays, O., Sirot, E., & Fritz, H. (2011). Collective Vigilance in the Greater Kudu: Towards a Better Understanding of Synchronization Patterns. Ethology, , no-no.
Abstract: Collective detection of predators is one of the main advantages of living in groups in prey species. However, the mechanisms linking individual and collective vigilance remain largely unknown. Here, we investigated individual and collective vigilance in a natural population of greater kudu (Tragelaphus strepsiceros), a gregarious ruminant living under high predation risk. Controlling for environmental, individual and group factors, we show that the proportion of time during which at least one individual was vigilant increased with group size, whereas individual investment in vigilance decreased. We also show that individuals tended to synchronize both vigilance and feeding activities. More generally, and whatever the considered group size, we demonstrate how the independent scanning assumption underestimated both the proportion of time during which no individual was vigilant and the proportion of time during which all individuals were simultaneously vigilant, but overestimated the proportion of time during which one vigilant individual only was present. Our results thus contrast with the point of view that the alternative to independent vigilance is coordinated vigilance and plead for a better description of the processes whereby reciprocal influences between individuals shape collective patterns of vigilance.
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Hobaiter, C., & Byrne, R. (2011). Serial gesturing by wild chimpanzees: its nature and function for communication. Anim. Cogn., 14(6), 827–838.
Abstract: Chimpanzees at Budongo, Uganda, regularly gesture in series, including ‘bouts’ of gesturing that include response waiting and ‘sequences’ of rapid-fire gesturing without pauses. We examined the distribution and correlates of 723 sequences and 504 bouts for clues to the function of multigesture series. Gesturing by older chimpanzees was more likely to be successful, but the success rate of any particular gesture did not vary with signaller age. Rather, older individuals were more likely to choose successful gestures, and these highly successful gestures were more often used singly. These patterns explain why bouts were recorded most in younger animals, whereas older chimpanzees relied more on single gestures: bouts are best interpreted as a consequence of persistence in the face of failure. When at least one gesture of a successful type occurred in a sequence, that sequence was more likely to be successful; overall, however, sequences were less successful than single gestures. We suggest that young chimpanzees use sequences as a ‘fail-safe’ strategy: because they have the innate potential to produce a large and redundant repertoire of gestures but lack knowledge of which of them would be most efficient. Using sequences increases the chance of giving one effective gesture and also allows users to learn the most effective types. As they do so, they need to use sequences less; sequences may remain important for subtle interpersonal adjustment, especially in play. This ‘Repertoire Tuning’ hypothesis explains a number of results previously reported from chimpanzee gesturing.
Keywords: Biomedizin & Life Sciences
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Gaunet, F., & Deputte, B. (2011). Functionally referential and intentional communication in the domestic dog: effects of spatial and social contexts. Animal Cognition, 14(6), 849–860.
Abstract: In apes, four criteria are set to explore referential and intentional communication: (1) successive visual orienting between a partner and distant targets, (2) the presence of apparent attention-getting behaviours, (3) the requirement of an audience to exhibit the behaviours, and (4) the influence of the direction of attention of an observer on the behaviours. The present study aimed at identifying these criteria in behaviours used by dogs in communicative episodes with their owner when their toy is out of reach, i.e. gaze at a hidden target or at the owner, gaze alternation between a hidden target and the owner, vocalisations and contacts. In this study, an additional variable was analysed: the position of the dog in relation to the location of the target. Dogs witnessed the hiding of a favourite toy, in a place where they could not get access to. We analysed how dogs engaged in communicative deictic behaviours in the presence of their owner; four heights of the target were tested. To control for the motivational effects of the toy on the dogs’ behaviour and for the referential nature of the behaviours, observations were staged where only the toy or only the owner was present, for one of the four heights. The results show that gazing at the container and gaze alternation were used as functionally referential and intentional communicative behaviours. Behavioural patterns of dog position, the new variable, fulfilled the operational criteria for functionally referential behaviour and a subset of operational criteria for intentional communication: the dogs used their own position as a local enhancement signal. Finally, our results suggest that the dogs gazed at their owner at optimal locations in the experimental area, with respect to the target height and their owner’s (or their own) line of gaze.
Keywords: Biomedizin & Life Sciences
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Peeters, M., Sulon, J., Beckers, J. - F., Ledoux, D., & Vandenheede, M. (2011). Comparison between blood serum and salivary cortisol concentrations in horses using an adrenocorticotropic hormone challenge. Equine Veterinary Journal, 43(4), 487–493.
Abstract: Reasons for performing study: In horses, serum cortisol concentration is considered to provide an indirect measurement of stress. However, it includes both free and bound fractions. The sampling method is also invasive and often stressful. This is not the case for salivary cortisol, which is collected using a more welfare-friendly method and represents a part of the free cortisol fraction, which is the biologically active form. Objectives: To compare salivary and serum cortisol assays in horses, in a wide range of concentrations, using an adrenocorticotropic hormone (ACTH) stimulation test, in order to validate salivary cortisol for stress assessment in horse. Methods: In 5 horses, blood samples were drawn using an i.v. catheter. Saliva samples were taken using swabs. Cortisol was assayed by radioimmunoassay. All data were treated with a regression method, which pools and analyses data from multiple subjects for linear analysis. Results: Mean ± s.d. cortisol concentrations measured at rest were 188.81 ± 51.46 nmol/l in serum and 1.19 ± 0.54 nmol/l in saliva. They started increasing immediately after ACTH injection and peaks were reached after 96 ± 16.7 min in serum (356.98 ± 55.29 nmol/l) and after 124 ± 8.9 min in saliva (21.79 ± 7.74 nmol/l, P<0.05). Discharge percentages were also different (225% in serum and 2150% in saliva, P<0.05). Correlation between serum and salivary cortisol concentrations showed an adjusted r2= 0.80 (P<0.001). The strong link between serum and salivary cortisol concentrations was also estimated by a regression analysis. Conclusions: The reliability of both RIAs and regression found between serum and salivary cortisol concentrations permits the validation of saliva-sampling as a noninvasive technique for cortisol level assessment in horses.
Keywords: horse; cortisol; ACTH challenge; saliva; stress
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Krueger, K., & Farmer, K. (2011). Laterality in the Horse [Lateralität beim Pferd ]. mup, 4, 160–167.
Abstract: Horses are one-sided, not only on a motor level, but they also prefer to use one eye, ear or nostril over the other under particular circumstances. Horses usually prefer using the left eye to observe novel objects and humans. This preference is more marked in emotional situations and when confronted with unknown persons. Thus the horse’s visual laterality provides a good option for assessing its mental state during training or in human-horse interactions. A strong preference for the left eye may signal that a horse cannot deal with certain training situations or is emotionally affected by a particular person.
Pferde benutzen für die Begutachtung von Objekten und Menschen bevorzugt eine bestimmte Nüster, ein Ohr oder ein Auge. So betrachten die meisten Pferde Objekte und Menschen mit dem linken Auge. Die Lateralitätsforschung erklärt diese sensorische Lateralität mit der Verarbeitung von Informationen unterschiedlicher Qualität in verschiedenen Gehirnhälften und zeigt auf, dass positive und negative emotionale Informationen sowie soziale Sachverhalte mit dem linken Auge aufgenommen und vorwiegend an die rechte Gehirnhälfte weitergegeben werden. In diesem Zusammenhang ermöglicht die visuelle Lateralität, den Gemütszustand des Pferdes im Training und im therapeutischen Fördereinsatz zu erkennen und zu berücksichtigen. |
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Krueger K., F. K., Byrne R. (2011). The use of sensory laterality for indicating emotional and cognitive reactions on environmental stimuli in animals [Die sensorische Lateralität als Indikator für emotionale und kognitive Reaktionen auf Umweltreize beim Tier]. In M. Erhard, U. Pollmann, B. Puppe, K. Reiter, & S. Waiblinger (Eds.), Current research in applied ethology [Aktuelle Arbeiten zur artgemäßen Tierhaltung (pp. 13–23). Darmstadt: KTBL.
Abstract: Summary
Many animals are lateralized when using sensory organs such as the eyes, ears or nostrils. Sensory laterality is not, as previously believed, caused by adjustment to motor laterality, but rather by one sided information processing in the particular brain hemi-spheres. While the right hemisphere predominantly analyses emotional information, the left hemisphere governs controlled rational, cognitive decisions. Since the brain hemi-spheres are largely connected with contralateral sensory organs, it is possible to infer how the information may be being interpreted by the side of preferred eye, ear or nostril used. The left eye usually dominates in emotional situations, i.e. fear or positive ex-citement, and the right eye in rational situations. Moreover, laterality increases when animals are stressed, e.g. when animals are confronted with anthropogenic or natural factors they can not handle, such as unsuitable housing or training conditions or un-avoidable predation pressure and social competition. A strong or increasing laterality could therefore potentially indicate welfare issues. Zusammenfassung Viele Tiere zeigen eine eindeutige sensorische Lateralität, sprich sie benutzen bevor-zugt ein Auge, ein Ohr, oder eine Nüster zur Aufnahme von Sinneseindrücken. Dies korreliert in den meisten Fällen nicht mit der motorischen Lateralität, sondern wird viel mehr durch die einseitige Verarbeitung von Informationen in den jeweiligen Gehirnhe-misphären bedingt. So werden emotionale Reaktionen von der rechten, reaktiven Ge-hirnhemisphäre und rationale Reaktionen von der linken, kognitiven Gehirnhemisphäre gesteuert. Da die Gehirnhälften zum Großen Teil mit den kontrolateralen Sinnesorga-nen verbunden sind lässt die Seite mit welcher Sinneseindrücke aufgenommen werden Schlüsse auf deren Informationsgehalt zu. So zeigen Tiere bei linksseitiger Aufnahme von Sinneseindrücken vermehrt reaktive, emotionalen Reaktionen, wie etwa bei Angst oder freudige Erregung, und bei rechtsseitig aufgenommene Sinneseindrücke eher rationales, gesteuertes Verhalten. Zudem verstärkt sich die sensorische Lateralität wenn Tiere Stress erfahren, sprich wenn sie wiederholt mit Situationen anthropogenen oder natürlichen Ursprungs konfrontiert werden denen sie nicht gewachsen sind, wie etwa bei unpassenden Haltungs- und Trainingsbedingungen, oder bei unausweichli-chem Raubtierdruck und sozialer Konkurrenz. Eine stark ausgeprägte, zunehmende sensorische Lateralität kann daher auf ein beeinträchtigtes Wohlergehen der Tiere hinweisen. |
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Uchiyama, H., Ohtani, N., & Ohta, M. (2011). Three-dimensional analysis of horse and human gaits in therapeutic riding. Appl. Anim. Behav. Sci., 135(4), 271–276.
Abstract: Therapeutic horse riding or hippotherapy is used as an intervention for treating individuals with mental and physical disabilities. Equine-assisted interventions are based on the hypothesis that the movement of the horse's pelvis during horseback riding resembles human ambulation, and thus provides motor and sensory inputs similar to those received during human walking. However, this hypothesis has not been investigated quantitatively and qualitatively. This study aimed to verify the hypothesis by conducting a three-dimensional analysis of the horse's movements while walking and human ambulation. Using four sets of equipments, we analysed the acceleration patterns of walking in 50 healthy humans and 11 horses. In addition, we analysed the exercise intensity by comparing the heart rate, breathing rate, and blood pressure of 127 healthy individuals before and after walking and horse riding. The acceleration data series of the stride phase of horse walking were compared with those of human walking, and the frequencies (in Hz) were analysed by Fast Fourier transform. The acceleration curves of human walking overlapped with those of horse walking, with the frequency band of human walking corresponding with that of horse walking. Exercise intensity, as measured by the heart rate and breathing rate, was not significantly different between horse riding and human walking. The levels of diastolic blood pressure were slightly higher during horse riding than during walking, but were lower during both conditions compared with those in normal conditions (P < 0.01). The present study shows that, although not completely matched, the accelerations of the horse and human walking are comparable quantitatively and qualitatively. Horse riding at a walking gait could generate motor and sensory inputs similar to those produced by human walking, and thus could provide optimum benefits to persons with ambulatory difficulties.
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König von Borstel, U., Pasing, S., & Gauly, M. (2011). Towards a more objective assessment of equine personality using behavioural and physiological observations from performance test training. Appl. Anim. Behav. Sci., 135(4), 277–285.
Abstract: Current definitions of horse personality traits are rather vague, lacking clear, universally accepted guidelines for evaluation in performance tests. Therefore, the aim of the present study was to screen behavioural and physiological measurements taken during riding for potential links with scores the same horses received in the official stallion performance test for rideability and personality traits. Behaviour, heart rate (HR) and HR variability from thirty-six stallions participating in a performance test were recorded repeatedly during their performance test training. Using the coefficient of determination, regression analysis revealed that about 1/3 of variation (ranging between r = 0.26 (“constitution” (i.e. fitness, health)) and r = 0.46 (rideability)) in the personality trait scores could be explained by selecting the three most influential behaviour patterns per trait. These behaviour patterns included stumbling (with all traits except character), head-tossing (temperament, rideability), tail-swishing (willingness to work), involuntary change in gait (character) and the rider's use of her/his hands (constitution, rideability), voice (temperament) or whip (constitution). Subsequent mixed model analysis revealed a significant (P < 0.05) influence of the behaviour pattern “horse-induced change in gait” on character (-0.98 ± 0.31 scores per additional occurrence of change in gaits), of head-tossing (-0.25 ± 0.08 scores) and rider's use of voice (-0.51 ± 0.25; P = 0.0594) on temperament, and of stumbling on each of the following: willingness to work (-2.5 ± 1.2), constitution (-2.5 ± 1.2 scores; P = 0.0516) and rideability scores (-3.3 ± 1.4). In addition, constitution scores tended (P = 0.0889) to increase with higher low frequency/high frequency heart rate variation ratios (LF/HF), indicating a shift towards sympathetic dominance and thus a higher stress load in horses with higher scores for constitution. Rideability scores from the training phase were also significantly influenced by head-tossing (-0.5 ± 0.1), and in addition rideability scores from the final test were influenced by the training rider, ranging between average estimated rideability scores of 6.8 ± 0.4 for one training rider and 8.36 ± 0.3 scores for another training rider. Horses ridden with their nose-line predominantly behind the vertical received higher scores for rideability (8.3 ± 0.3) than horses ridden with their nose-line at the vertical (7.7 ± 0.2). These findings indicate that either judges perceive horses to have a better rideability when they readily offer a more extreme poll flexion, or that riders make use of horses’ better rideability by imposing a more extreme poll flexion. Several of the above described associations, but also of the non-existing links (e.g. no association between shying or heart rate and temperament) between behaviour patterns and scores for personality traits are rather surprising, warranting further investigation regarding the underlying causes of these relationships. Some of these behaviour patterns should be considered when redesigning the current guidelines for evaluation of personality traits during breeding horse performance tests, ultimately leading to improved genetic selection for equine personality traits. However, ethical implication of defining aversive behaviour such as head-tossing as an indicator of, for example, poor temperament, should not be neglected when devising new guidelines: such aversive behaviour may in fact be an indication of inadequate training techniques rather than poor horse personality.
Keywords: Horse; Personality; Behaviour; Heart rate variability; Riding; Performance test
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