Visually guided catching and tracking skills in pigeons: A preliminary analysis

Research on reaching, tracking, and catching in the pigeon has been hampered by limitations of technology. A new system was developed in which the target was a small rectangle presented on a video display terminal and the pecking response was detected with touch technology. The target moved up and down vertically with sinusoidal velocity. A coincidence between the location of the pigeon's beak and the cursor produced reinforcement. The pigeon pecked ahead and behind the target, but most pecks occurred behind the target so the dominant tracking strategy was lagging. The pigeon was adept at “catching” the target at many locations throughout the trajectory. Transfer of motor learning was tested on probe trials during which the trajectory changed from vertical to horizontal. On transfer trials the pigeons' dominant pattern of pecking immediately shifted from vertical to horizontal. The motor skill displayed by the pigeons was flexible and adaptive, suggesting that the pigeons had learned to track the cursor.     

Transfer of matching-to-figure samples in the pigeon

Three pigeons were trained on a modified six-key matching-to-sample procedure. The third peck on the figure-sample key (which presented a bird, hand, face, beetle, rabbit, fish, flower, or red hue, as the sample) lighted only one comparison key. Every three additional pecks on the sample lighted another comparison key, up to a maximum of five keys. Pecks on keys of matching figures produced grain. Pecks on nonmatching keys (mismatches) turned off all lights on the comparison keys and repeated the trial. Three figures were used during acquisition. The birds learned to peck each sample until the matching comparison stimulus appeared on one of three comparison stimulus keys, and then to peck that key. Later, five novel stimuli, employed as both sample and comparison stimuli, and two additional matching keys were added. Each bird showed matching transfer to the novel samples. The data suggest that the birds may have learned the concept of figure matching rather than a series of two-component chains or discrete five-key discriminations.     

情境理论的迁移观及其教育意义

支撑—活动观、社会共享认知观以及实践共同体观是当前情境理论中具有代表性的迁移观点。这些观点分别从不同的角度强调情境特性对迁移的影响,并主张在常规的学校教育中突出情境、尤其是社会文化与社会实践情境的作用。     

体验活动对冲动性购买行为的影响:情感反应视角

冲动性购买在商场和超市的零售中占有相当的比例,本研究以旅游者和旅游购物为实证研究对象,在323份调查问卷的基础上,采用方差分析和回归分析的方法探讨了体验活动对冲动性购买行为的影响及其情感反应机制。结果表明：在激发消费者冲动性购买行为方面,顾客参与的效果最好,其次是顾客学习,再次是顾客娱乐;顾客参与会导致更多的快乐的情感反应,而快乐的情感反应对冲动性购买意愿的影响最为显著;顾客学习会导致更多的支配的情感反应,而支配的情感反应对冲动性购买意愿的影响较为显著。     

Determination of a behavioral transfer function: White-noise analysis of session-to-session response-ratio dynamics on concurrent VI VI schedules

Six pigeons were exposed to concurrent variable-interval schedules in which the programmed reinforcer ratios changed from session to session according to a pseudorandom binary sequence. This procedure corresponded to the stochastic identification paradigm (“white-noise experiment”) of systems theory and enabled the relation between log response ratios in the current session and log reinforcer ratios in all previous sessions to be determined. Such dynamic relations are called linear transfer functions. Both nonparametric and parametric representations of these, in the form of “impulse-response functions,” were determined for each bird. The session-to-session response ratios resulting from the session-to-session pseudorandom binary variations in reinforcer ratios were well predicted by the impulse-response functions identified for each pigeon. The impulse-response functions were well fitted by a second-order dynamic model involving only two parameters: a time constant and a gain. The mean time constant was 0.67 sessions, implying that the effects of abrupt changes in log reinforcer ratios should be 96% complete within about five sessions. The mean gain was 0.53, which was surprisingly low inasmuch as it should equal the sensitivity to reinforcement ratio observed under steady-state conditions. The same six pigeons were subjected to a similar experiment 10 months following the first. Despite individual differences in impulse-response functions between birds within each experiment, the impulse-response functions determined from the two experiments were essentially the same.     

The stages of acquisition in stimulus fading

Pigeons were exposed to a stimulus fading procedure in which control of responding was transferred from red and black stimuli to lines of different angular orientation. After superimposing one line on the red stimulus and the other line on the black stimulus, the intensity of the lines was gradually increased and that of the red stimulus was gradually reduced. Probes consisting of red and line stimuli presented separately were used during the course of fading to assess control exerted by each element of the compound. As the lines were faded in, they did not acquire control of responding. As red was faded out, control of responding was acquired first by the lower intensity red stimuli in combination with the line stimulus, and finally by the angular orientation of the lines. Probes also determined the point at which the line stimuli, presented alone, would maintain a high degree of stimulus control. The results demonstrated that new stimuli in fading acquire dimensional control of responding in two sequential stages. Acquisition of stimulus control in fading was explained in terms of attenuation of stimulus blocking.     

Beyond conflict: Functional facets of the work-family interplay

The present paper deals with three positive facets of the work-family interplay, i.e., transfer of competencies, transfer of positive mood, and cross-domain compensation. The latter refers to the experience that engagement in one domain helps dealing with failures in the other domain. In two correlational studies (N₁ = 107 working mothers, N₂ = 146 working men and women), cross-domain compensation predicted domain-specific well-being even when we controlled for work-family conflicts and the two other positive facets (viz., transfer of competencies and positive mood). In an additional experiment (N₃ = 63 working men and women), which exclusively focused on compensation, participants were asked to remember a job-related failure. Then they were instructed to think about a positive job-related experience (i.e., intradomain compensation) or family-related experience (i.e., cross-domain compensation). Compared to a control group, both experimental groups showed faster emotional recovery, with cross-domain compensation being a slightly more effective strategy at the beginning of that recovery.     

多媒体环境下图文的具体程度对学习效果的影响

让70名小学生在多媒体环境中学习概念材料与原理材料,以探讨文本和图画材料的具体程度对学习迁移效果的影响。结果表明,在概念材料上,文本与图画的具体性程度之间存在显著的交互作用,即在具体图水平上,具体文的迁移成绩显著高于抽象文;在抽象图水平上,具体文的迁移成绩低于抽象文,但没有达到显著性水平。在原理材料上,文本与图画的具体性程度之间也存在显著的交互作用,但交互作用的方式与概念材料相反,即在具体图水平上,具体文的迁移成绩显著低于抽象文;在抽象图水平上,具体文的迁移成绩高于抽象文,但没有达到显著水平。     

Prospective Relations Between Organized Activity Participation and Psychopathology During Adolescence

This longitudinal study examined psychopathology as a predictor and outcome of organized activity involvement during high school among 198 adolescents who varied in risk for psychopathology as a function of their mother's depression history. Higher levels of internalizing and externalizing symptoms in eighth grade significantly predicted lower levels of involvement in academic clubs during high school, over and above risk and SES. Tobacco use prior to high school predicted lower levels of involvement overall and in academic clubs and performance arts. Controlling for psychopathology prior to high school, higher levels of activity involvement were associated with lower levels of externalizing symptoms, less tobacco use, and fewer diagnoses of behavior disorders and substance abuse in 12th grade. The positive association between risk and adolescent psychopathology was not buffered by adolescent activity involvement. Overall, these findings suggest that involvement in organized activities may contribute to lower levels of externalizing psychopathology during high school even when controlling for prior psychopathology.     

On Biotechnology,Theology, and the Human Sciences

There may be very good Christian theological reasons to oppose human biotechnological enhancement. It is, however, difficult to discern what they are. Much of the specifically Christian response to transhumanist biotechnological enhancement has revolved around the metaphysics of human persons; this is hardly surprising, given that similar themes appear in other bioethical themes, such as over in vitro fertilization, abortion, and euthanasia. The main aim of this paper is to clarify the theological requirements for such responses, particularly those that are mistakenly delegated to scientists. In particular, the paper will focus on the need for a Christian theological account of human nature that does not unduly rely on biological accounts of the same.