Abstract: By definition, punishment makes a response less likely in the future. Because horses are largely trained by negative reinforcement, they are susceptible to inadvertent punishment. Delays in the release of pressure can make desirable responses less likely and thus punish them. This study examines the correct use of negative reinforcement and identifies a continuum between poorly timed negative reinforcement and punishment. It explores some of the problems of non-contingent punishment and the prospect of learned helplessness and experimental neurosis. It concludes by introducing the concept of ethical equitation.

Abstract: Sixteen horses were used to determine if number of trials given per training session (5, 10, 15 or 20) affected learning performance in an avoidance conditioning task. The horse had to move from one side of a test pen to the other during an auditory cue presentation to avoid aversive stimulation. A pen 8 mx3.6 m, divided into two equal sections by a 13-cm diameter plastic pipe lying on the ground, was used as the test pen. Painted plywood panels were fastened to the fence in half the pen to help horses distinguish visually between the two parts. A 10-s auditory cue was used as a signal for horses to move from one side of the test pen to the other. A 20-s intertrial interval was used. Training sessions were conducted every third day. Each trial was recorded as an avoidance (the horse completed the task during auditory cue presentation and avoided aversive stimulus) or an error (the horse received aversive stimulus). After completing ten consecutive avoidances (criterion), the horse was removed from the study. Numbers of training sessions, trials, avoidances and errors until reaching criterion were recorded for each horse. Horses varied greatly within these variables with ranges of 3-18 sessions, 37-121 trials, 20-68 avoidances and 17-53 errors to criterion. No differences were detected (P>0.05) in the number of conditioning trials per training session (treatment) for the mean number of trials, avoidances or errors to criterion. Number of training sessions to criterion differed (P<0.01) among treatments, indicating that an optimum number of learning trials per training session might exist. Mean sessions to criterion for horses receiving 5, 10, 15 and 20 trials per session were 15.1+/-1.3, 5.8+/-1.1, 5.3+/-1.1 and 4.6+/-1.1, respectively. Regression analysis indicated that 16.2 trials per training session would minimize number of sessions to criterion. Although it is widely assumed that learning efficiency in horses is decreased when intense activity is concentrated into a small number of sessions, these results indicate that moderate repetition of training activities is needed for efficient learning.

Abstract: Reliable physiological markers for performance evaluation in sport horses are missing. To determine the diagnostic value of plasma ACTH and cortisol measurements in the warmblood horse, 10 initially 3-yr-old geldings of the Hannovarian breed were either exposed to a training schedule or served as controls. During experimental Phase 1, horses were group-housed, and half of the horses were trained for 20 wk on a high-speed treadmill. During Phase 2, groups were switched and one group was trained for 10 wk as during Phase 1, whereas the control group was confined to boxes. During Phase 3 horses were initially schooled for riding. Thereafter, all horses were regularly schooled for dressage and jumping, and half of the horses received an additional endurance training for 24 wk. During all phases horses were exposed at regular intervals to various standardized treadmill exercise tests. During and after the tests frequent blood samples were taken from an indwelling jugular catheter for determination of ACTH and cortisol. Treadmill exercise increased both hormones. Maximum ACTH concentrations were recorded at the end of exercise, and maximum cortisol levels were recorded 20 to 30 min later. Except for one test there were no differences in ACTH levels between trained horses and controls. There was no significant effect of training on the cortisol response (net increase) to treadmill exercise in any of the tests during Phase 1. During Phase 2 higher cortisol responses were recorded in controls than in trained horses (P < .05) after 10 wk of training (controls confined to boxes). During Phase 3 plasma cortisol responses were also higher in controls than in trained horses (P < .05 after 6, 18, and 24, P < or = .07 after 12 wk of training) when the inclination of the treadmill was 5%, but not at 3%. There was no overlap in net cortisol responses at 30 min between trained and untrained horses. An ACTH application after 24 wk of training resulted in higher cortisol responses in controls than in trained horses (P < or = .05), without any overlap between the groups at 30 min after ACTH. Plasma cortisol responses to either treadmill exercise or ACTH injection may be a reliable physiological marker for performance evaluation. Prerequisites are sufficient differences in training status and sufficient intensity of exercise test conditions.

Abstract: The work of behavioural pharmacologists has concentrated on small animals, such as rodents and pigeons. The validity of extrapolation of their findings to humans depends upon the existence of parallels in both physiology and psychology between these animals and humans. This paper considers the question whether there are in fact substantial cognitive parallels between, first, different non-human groups of vertebrates and, second, non-humans and humans. Behavioural data from 'simple' tasks, such as habituation and conditioning, do not point to species differences among vertebrates. Using examples that concentrate on the performance of rodents and birds, it is argued that, similarly, data from more complex tasks (learning-set formation, transitive inference, and spatial memory serve as examples) reveal few if any cognitive differences amongst non-human vertebrates. This conclusion supports the notion that association formation may be the critical problem-solving process available to non-human animals; associative mechanisms are assumed to have evolved to detect causal links between events, and would therefore be relevant in all ecological niches. In agreement with this view, recent advances in comparative neurology show striking parallels in functional organisation of mammalian and avian telencephalon. Finally, it is argued that although the peculiarly human capacity for language marks a large cognitive contrast between humans and non-humans, there is good evidence-in particular, from work on implicit learning--that the learning mechanisms available to non--humans are present and do play an important role in human cognition.