Abstract: Among equestrians the “natural” training methods of horses are gaining widespread popularity due to their spectacular efficiency. Underlying philosophy of trainers – founders of different “natural horsemanship training” (NHT) schools, along with other not well documented statements includes argumentation of solely welfare- and human-friendly effects of NHT in the horse. The aim of this review was to screen scientific papers related to NHT to answer the question whether „natural“ training methods may actually exert only positive effects upon equine mental state and human-horse relationship. It appears that NHT trainers may reduce stress and emotional tension and improve learning processes as they appropriately apply learning stimuli. Basing on revised literature it can be concluded that training is successful provided that [i] the strength of the aversive stimulus meets sensitivity of an individual horse, [ii] the aversive stimulus is terminated at a right moment to avoid the impression of punishment, and [iii] the animal is given enough time to assess its situation and make an independent decision in the form of adequate behavioural reaction. Neglecting any of these conditions may lead to substantial emotional problems, hyperactivity, or excessive fear in the horse-human relationship, regardless of the training method. However, we admit that the most successful NHT trainers reduce aversive stimulation to the minimum and that horses learn quicker with fear or stress reactions, apparently decreasing along with training process. Anyway, NHT should be acknowledged for absolutely positive role in pointing out the importance of proper stimulation in the schooling and welfare of horses.

Abstract: Hearst and Jenkins proposed in 1974 that elicited responding accounts for the feature-positive effect. To test this position, pigeons were exposed to a feature-positive or feature-negative discrimination between successively presented displays--one consisted of a red and a green response key and the other consisted of two green response keys. There were four main conditions: 5-5 (5-sec trials, 5-sec intertrial intervals), 5-30, 30-30, and 30-180. Conditions 5-30 and 30-180 should produce the largest amount of elicited responding, and therefore the largest feature-positive effects. A response-independent bird was yoked to each response-dependent bird to allow direct assessment of the amount of elicited responding generated by each condition. Contrary to the predictions by Hearst and Jenkins's theory, response-dependent birds showed large feature-positive effects in each condition. The largest feature-positive effect was obtained in condition 5-5. Response-independent birds produced similar results, but manifested low response rates.

Abstract: Conflict management is one of the primary requirements for social complexity. Of the many forms of conflict management, one of the rarest and most interesting is third-party policing, or intervening impartially to control conflict. Third-party policing should be hard to evolve because policers personally pay a cost for intervening, while the benefits are diffused over the whole group. In this study we investigate the incidence and costs of policing in a primate society. We report quantitative evidence of non-kin policing in the nonhuman primate, the pigtailed macaque. We find that policing is effective at reducing the intensity of or terminating conflict when performed by the most powerful individuals. We define a measure, social power consensus, that predicts effective low-cost interventions by powerful individuals and ineffective, relatively costly interventions by low-power individuals. Finally, we develop a simple probabilistic model to explore whether the degree to which policing can effectively reduce the societal cost of conflict is dependent on variance in the distribution of power. Our data and simple model suggest that third-party policing effectiveness and cost are dependent on power structure and might emerge only in societies with high variance in power.

Abstract: A grooming posture previously reported for two wild chimpanzee (Pan troglodytes) communities developed spontaneously in a captive group of the same species. This offered a unique opportunity to follow the propagation of a new social custom. The posture consists of two partners grasping hands--either both right hands or both left hands--and raising the arms in an A-frame above their heads while mutually grooming with their free hands. The propagation of this pattern was followed over a 5 year period. In the beginning, handclasps were always initiated by the same adult female. This female initiated the posture mainly with her adult female kin. In subsequent years, these relatives became frequent participants in the posture with each other as well as with nonrelatives. Over the years the posture increased in frequency and duration and spread to the majority of adults and also to a few adolescents and older juveniles. The pattern persisted after removal of the apparent originator.