The effects of differential reinforcement of vocal duration were examined in a series of experiments in which each of 28 subjects (Ss) emitted a vowel whenever a light was flashed. In the first phase of each experiment, a penny was dispensed after each of 20 responses. In the second and subsequent phases, only those responses whose durations exceeded a criterion were reinforced; when 10 successive reinforcements were presented, one phase was terminated and the next begun. The criterion for reinforcement in each phase was determined by a different schedule in each of six experiments; it ranged from 80 to 120 per cent of the mean duration of the 10 terminal responses in the prior phase. Differential reinforcement effected a large and systematic change in the duration of vocal responses as long as the responses selected for reinforcement had a sufficiently high probability of occurrence. This requirement was formulated as the difference between the criterion duration and the mean duration of the terminal responses in the prior phase, divided by their standard deviation. This statistic, named the shaping index, was correlated with the number of responses emitted before each phase was terminated. It was found to be large whenever the shaping process failed. Many Ss failed to tact the reinforcement contingency despite marked changes in their vocal behavior and extensive probing by a questionnaire, administered at the end of each session. 相似文献
Observers make rapid eye movements to examine the world around them. Before an eye movement is made, attention is covertly shifted to the location of the object of interest. The eyes typically will land at the position at which attention is directed. Here we report that a goal-directed eye movement toward a uniquely colored object is disrupted by the appearance of a new but task-irrelevant object, unless subjects have a sufficient amount of time to focus their attention on the location of the target prior to the appearance of the new object. In many instances, the eyes started moving toward the new object before gaze started to shift to the color-singleton target. The eyes often landed for a very short period of time (25–150 ms) near the new object. The results suggest parallel programming of two saccades: one voluntary, goal-directed eye movement toward the color-singleton target and one stimulus-driven eye movement reflexively elicited by the appearance of the new object. Neuroanatomical structures responsible for parallel programming of saccades are discussed. 相似文献
Previous research has shown that during visual search young and old adults' eye movements are equivalently influenced by the appearance of task-irrelevant abrupt onsets. The finding of age-equivalent oculomotor capture is quite surprising in light of the abundant research suggesting that older adults exhibit poorer inhibitory control than young adults on a variety of different tasks. In the present study, we examined the hypothesis that oculomotor capture is age invariant when subjects' awareness of the appearance of task-irrelevant onsets is low, but that older adults will have more difficulty than young adults in inhibiting reflexive eye movements to task-irrelevant onsets when awareness of these objects is high. Our results were consistent with the level-of-awareness hypothesis. Young and old adults showed equivalent patterns of oculomotor capture with equiluminant onsets, but older adults misdirected their eyes to bright onsets more often than young adults did. 相似文献
Classical informal reasoning "fallacies," for example, begging the question or arguing from ignorance, while ubiquitous in everyday argumentation, have been subject to little systematic investigation in cognitive psychology. In this article it is argued that these "fallacies" provide a rich taxonomy of argument forms that can be differentially strong, dependent on their content. A Bayesian theory of content-dependent argument strength is presented. Possible psychological mechanisms are identified. Experiments are presented investigating whether people's judgments of the strength of 3 fallacies--the argumentum ad ignorantiam, the circular argument or petitio principii, and the slippery slope argument--are affected by the factors a Bayesian account predicts. This research suggests that Bayesian accounts of reasoning can be extended to the more general human activity of argumentation. 相似文献
Findings across a wide body of research suggest that media targeted at young audiences often portray characters according to stereotypical gender roles. Childhood is a particularly sensitive time in gender identity development, and logic from social cognitive theory suggests that repeatedly observing these stereotypes can have a lasting influence on young audiences’ worldview. Building on previous research investigating gender role displays in film content, and with the expectation that content creators use movie posters to convey a one-shot summary of films to audiences, we conducted a content analysis on the gendered power depictions of the main characters in movie posters of 152 popular U.S. animated children’s feature films produced over the last 80 years. Findings revealed that main characters were more likely to be male and that males were portrayed as more powerful. These results add to a growing, yet substantial, body of research illustrating the prevalence of stereotypical gender role portrayals across virtually every popular medium with which children come into contact. We discuss our results’ implications for potential short-term and long-term effects of exposure to films’ gender role stereotypes on young viewers’ real-life gender role expectations.
Patients with schizophrenia demonstrate marked impairments on most clinical neuropsychological tests. These findings suggest
that patients suffer from a generalized form of cognitive impairment, with little evidence of spared performance documented
in several large meta-analytic reviews of the clinical literature. In contrast, we review evidence for relative sparing of
aspects of attention, procedural memory, and emotional processing observed in studies that have employed experimental approaches
adapted from the cognitive and affective neuroscience literature. These islands of preserved performance suggest that the
cognitive deficits in schizophrenia are not as general as they appear to be when assayed with clinical neuropsychological
methods. The apparent contradiction in findings across methods may offer important clues about the nature of cognitive impairment
in schizophrenia. The documentation of preserved cognitive function in schizophrenia may serve to sharpen hypotheses about
the biological mechanisms that are implicated in the illness. 相似文献
How well we are attuned to the statistics of our environment is a fundamental question in understanding human behaviour. It seems particularly important to be able to provide accurate assessments of the probability with which negative events occur so as to guide rational choice of preventative actions. One question that arises here is whether or not our probability estimates for negative events are systematically biased by their severity. In a minimal experimental context involving an unambiguous, objective representation of probability, we found that participants judged a controllable event as more likely to occur when its utility was extremely negative than when it was more neutral. A decision-theoretic explanation based on loss function asymmetries is advanced which supports the claim that probability estimates are not intrinsically biased by utilities. 相似文献
Using a visual search paradigm, we investigated how a top-down goal modified attentional bias for threatening facial expressions.
In two experiments, participants searched for a facial expression either based on stimulus characteristics or a top-down goal.
In Experiment 1, participants searched for a discrepant facial expression in a homogenous crowd of faces. Consistent with
previous research, we obtained a shallower response time (RT) slope when the target face was angry than when it was happy.
In Experiment 2, participants searched for a specific type of facial expression (allowing a top-down goal). When the display
included a target, we found a shallower RT slope for the angry than for the happy face search. However, when an angry or happy
face was present in the display in opposition to the task goal, we obtained equivalent RT slopes, suggesting that the mere
presence of an angry face in opposition to the task goal did not support the well-known angry face superiority effect. Furthermore,
RT distribution analyses supported the special status of an angry face only when it was combined with the top-down goal. On
the basis of these results, we suggest that a threatening facial expression may guide attention as a high-priority stimulus
in the absence of a specific goal; however, in the presence of a specific goal, the efficiency of facial expression search
is dependent on the combined influence of a top-down goal and the stimulus characteristics. 相似文献