|
Miller J,. (1986). National forest management of wild horses and burros: Current position and policy. J Equine Vet Sc, 6, 259–260.
|
|
Turner Jw, K. J. (1986). Fertility control as a management tool for feral horse populations. J Equine Vet Sc, 6, 278–284.
|
|
Turner Jw, K. J. (1986). Hormones and reproduction in feral horses. J Equine Vet Sc, 6, 250–258.
|
|
White Dj,. (1986). The american humane association: Position on wild horse management. J Equine Vet Sc, 6, 276–277.
|
|
Wolfe Ml,. (1986). Population dynamics of feral horses in western North America. J Equine Vet Sc, 6, 231–235.
|
|
Berg Wa,. (1986). Effective population size estimates and breeding in feral horses: A preliminary assessment. J Equine Vet. Sc., 6, 240–245.
|
|
Boyles Js,. (1986). Managing America's wild horses and burros. J Equine Vet. Sc., 6, 261.
|
|
Smith Ma,. (1986). Potential competitive interactions between feral horses and other grazing animals. J Equine Vet. Sc., 6, 238–239.
|
Biederman, G. B., Robertson, H. A., & Vanayan, M. (1986). Observational learning of two visual discriminations by pigeons: a within-subjects design. J Exp Anal Behav, 46(1), 45–49.
Abstract: Pigeon's observational learning of successive visual discrimination was studied using within-subject comparisons of data from three experimental conditions. Two pairs of discriminative stimuli were used; each bird was exposed to two of the three experimental conditions, with different pairs of stimuli used in a given bird's two conditions. In one condition, observers were exposed to visual discriminative stimuli only. In a second condition, subjects were exposed to a randomly alternating sequence of two stimuli where the one that would subsequently be used as S+ was paired with the operation of the grain magazine. In a third experimental condition, subjects were exposed to the performance of a conspecific in the operant discrimination procedure. After exposures to conspecific performances, there was facilitation of discriminative learning, relative to that which followed exposures to stimulus and reinforcement sequences or exposures to stimulus sequences alone. Exposure to stimulus and food-delivery sequences enhanced performance relative to exposure to stimulus sequences alone. The differential effects of these three types of exposure were not attributable to order effects or to task difficulty; rather, they clearly were due to the type of exposure.
|
Zentall, T. R., Jackson-Smith, P., Jagielo, J. A., & Nallan, G. B. (1986). Categorical shape and color coding by pigeons. J Exp Psychol Anim Behav Process, 12(2), 153–159.
Abstract: Categorical coding is the tendency to respond similarly to discriminated stimuli. Past research indicates that pigeons can categorize colors according to at least three spectral regions. Two present experiments assessed the categorical coding of shapes and the existence of a higher order color category (all colors). Pigeons were trained on two independent tasks (matching-to-sample, and oddity-from-sample). One task involved red and a plus sign, the other a circle and green. On test trials one of the two comparison stimuli from one task was replaced by one of the stimuli from the other task. Differential performance based on which of the two stimuli from the other task was introduced suggested categorical coding rules. In Experiment 1 evidence for the categorical coding of sample shapes was found. Categorical color coding was also found; however, it was the comparison stimuli rather than the samples that were categorically coded. Experiment 2 replicated the categorical shape sample effect and ruled out the possibility that the particular colors used were responsible for the categorical coding of comparison stimuli. Overall, the results indicate that pigeons can develop categorical rules involving shapes and colors and that the color categories can be hierarchical.
|
