Selective attention and the breadth of learning: A developmental study

Nursery school and second-grade subjects were trained on an optional intradimensional/extradimensional shift task with (1) no overtraining, (2) overtraining on the initial problem only, (3) overtraining on the shift problem only, or (4) overtraining on both the initial and the shift problems. Predictions concerning the effects of age and training conditions on the type of solution and the breadth of learning for the shift problem were derived from selective attention theory. However, the results were not consistent with the one-look assumption of such models. Instead, a multiple-look theory in which the breadth of attention varies with task demands seems most tenable.     

The child's memory for actional, locational, and serial scenes

Three-, four-, and six-year-old children (N = 180) were tested for recall of a toy missing from a previously seen display of four toys. Toys were displayed initially as a series (StoS), as a unit (UtoU), or moved from a series to a unit as S watched (StoU). There was a significant increase in memory for the missing toy with age. In addition, children viewing StoU displays remembered significantly more toys than did children viewing the other displays, independent of age. Twenty-five percent of the 6-year-olds rehearsed spontaneously while viewing the displays. Results indicated that the nature of a memory unit does not change with age, that memory improves with age, and that separate visual and verbal memories are operative in Ss in this age range.     

The development of procedures for identifying competitive behavior in children

This study identified events in the competitive process that could be employed to discriminate between competition and individual, non-social behaviors. When children competed they overtly sought out information on how they were doing vis-à-vis their fellow competitor. In addition, their performance was a function of some competitive contingency: a reward for surpassing another. The procedures developed in this study were designed to manipulate competitive contingencies while observing their effects on task performance and social comparisons. The investigator could thus infer that competition was present when (1) subjects sought out information on how they were doing, as well as how another was doing on comparable tasks during competitive contingencies, and (2) their task performance was a function of the competitive contingency.     

Audience reaction as a determinant of the speaker's self-persuasion

This paper tests effects of audience feedback on speaker attitudes. One hundred and seven male subjects with initial beliefs on both sides of an issue (women's role) were assigned to speak for or against their own position; then an “audience” provided one of three types of feedback (speaker was sincere, speaker was insincere, no feedback) in a 2 × 2 × 3 design. Subjects who received sincere feedback showed greater change in the direction of their speech than did those who received insincere feedback. No feedback treatments resulted in intermediate change. This sincere > no feedback > insincere ordering of means held for both pro- and counterattitudinal speakers and for both pretest attitudes. A main effect for pretest attitude was also obtained. Two additional control groups allow for a separate analysis of the effects of (1) preparing and delivering the speech, and (2) audience reaction to the speech.     

Inducing ordinal and cardinal representations of the first five natural numbers

The prediction that the ordinal property of natural number symbols (using these symbols to represent the terms in an ordered progression) is more easily learned than the cardinal property of natural number symbols (using these symbols to represent the manyness of collections) was examined in this experiment. Preschoolers who evidenced no proficiency with either the ordinal or cardinal properties of natural number symbols were trained to acquire these properties via simple feedback. Both properties proved to be trainable. The most important findings were that the ordinal property was much easier to train than the cardinal property, ordinal training effects were more durable across a 1-week interval than cardinal training effects, and ordinal training appeared to transfer better than cardinal training.     

Positive contrast obtained in reacquisition following interpolation of nonreinforced or partially reinforced trials

Two experiments investigated the effects of shifting from either nonreinforcement or partial reinforcement (PRF) to continuous reinforcement conditions (CRF). In the first experiment, three groups of rats were given food reinforcement under CRF conditions in a runway followed by regular extinction trials (RE), extinction trials where Ss were delayed for 30 sec before entering the empty goal box (DE), or CRF trials where Ss were delayed for 30 sec before entering the baited goal box (DF). Then all Ss were run on the delayed reinforcement condition (DF). In the final delayed reinforcement condition, group DE ran significantly faster than group DF, reflecting positive contrast. In the second experiment, four groups of rats were trained in a runway to receive either 4% or 18% sucrose reinforcers under either PRF or CRF conditions. Then all Ss were transferred to a Skinner box and bar presses were continuously reinforced, with each S continuing to receive the same sucrose concentration as before. The former PRF Ss, regardless of the reinforcer, bar pressed at a significantly higher rate in the Skinner box than the former CRF Ss. The evidence seemed to favor the view that the effectiveness of a reinforcer is not an absolute, unchanging quantity but rather depends on the historical context in which the reinforcer occurs.     

Production deficits in aphasia: A voice-onset time analysis

An experimental study was conducted to examine phonetic and phonemic deficits in the speech production of aphasics. Subjects included four Broca's aphasics, four Conduction aphasics, five Wernicke's aphasics, one nonaphasic dysarthric patient, and four normal controls. The subjects read a list of words containing word-initial stop consonants which were subsequently measured acoustically for voice-onset time. The results showed that Broca's aphasics exhibit a more severe production disorder than Conduction aphasics who in turn exhibit a more severe disorder than Wernicke's aphasics, in accord with clinical observations. In addition, although Broca's aphasics produced both phonetic and phonemic errors, the results showed that they have a pervasive phonetic disorder which affects their correct target productions as well as the total number of phonetic errors produced. This deficit however seems to be a speech deficit rather than a low-level motor control problem. In contrast, the Wernicke's aphasics show a deficit characterized by isolated phonemic mistargeting errors. Finally, the pattern of productions for the Conduction aphasics indicates that some patients show a predominantly phonetic disorder similar to the Broca's aphasics and others show predominantly a phonemic disorder similar to the Wernicke's aphasics.     

Electrode placement,EMG feedback,and relaxation for tension headaches

Fifteen tension headache subjects were allocated to one of three groups: direct EMG feedback (from a site corresponding to the source of pain), indirect EMG feedback (from a site not corresponding to the source of the pain) and relaxation instructions. There were two base-line, six treatment and one post-treatment sessions. No significant differences were found between base-line and post-treatment EMG levels, for any of the groups; however, some significant reductions in levels were obtained within sessions. EMG levels recorded during headache attacks did not differ significantly from levels recorded during base-line. Frequency and intensity of headaches were significantly reduced, particularly in the relaxation group. At follow-up this improvement was maintained for subjects with forehead pain, but differences between the groups had disappeared.     

外科临床决策的核心在精于选择

造就名医是个系统工程,理论和实践统一才有功底。为病人提供优质服务,要求医生有能力对病情进行综合分析思考、辨认、评估,对诊断、治疗进行鉴别,为选择科学的临床决策提供依据。理论与临床实践高水平的结合,难能可贵的是忌粗取精、忌浅求深、忌表识里,从临床汇集资料来思考、分析,最终做出选择,再到临床上去验证,从而得出正确的诊断和处理方案。善于选择和精于选择,是临床决策的核心,是临床医生综合素质走向成熟的产物,是一代名医成长的必然之路。