Speed-accuracy tradeoff in double stimulation: Effects on the first response

A single-stimulation and two double-stimulation response conditions were compared using explicit payoff matrices to vary speed-accuracy tradeoff. Under accuracy payoff, response latency (RT(1)) to the first stimulus increased as ISI dropped but accuracy remained high and relatively constant. Under speed payoff, RT(1) was only slightly affected by ISI but accuracy dropped as ISI decreased. Transmitted information rates consistently reflected detrimental effects of short ISI. In double stimulation, but not in single stimulation, error response latency exceeded correct response latency. Furthermore, error response latencies were found to be far more variable and more sensitive to changes in speed-accuracy condition than were correct response latencies. Finally, under both speed and accuracy conditions, response latency to the first of two successive stimuli was faster if a response was also required to the second stimulus. Implications of the data for possible models of double-stimulation speed-accuracy tradeoff are considered.     

An experiment control computer system time shared by several laboratories

An experiment control computer system, operational for more than 2 years, is discussed. The system is multiprogammed, using a vendor supplied real-time operating system. Individual experiments employ multitasking—fast response functions are implemented in core resident tasks while interactive and other slow response functions are implemented in tasks that operate under time sharing. The areas of psychological research currently supported are concept formation studies, EEG evoked response studies, monitoring the autonomic nervous system, perception studies, and family interaction studies.     

A simple electrode to record fetal EEG for optimal signal analysis

A simple EEG electrode for Intrauterine use In the human fetus is described. The stainless steel screw electrode possesses low noise characteristics, is constructed from commercially available material, and is easily attached to the fetal head during labor. Principles of optical signal analysis as an improved method of spectral analysis of the fetal EEG are also presented. The optical system provides visual display and hard copy output of the fetal EEG.     

Social motives among Anglo American and Mexican American children: Experimental and projective measures

The measurement approaches to social motives, cooperation-competition games and projective tests, have revealed apparently similar findings: Anglo American children are more competitive and higher in n Achievement compared to Mexican American children, who are more cooperative and higher in n Affiliation. The present experiment tested the extent to which (1) competitiveness is related to n Achievement, (2) cooperativeness is related to n Affiliation, and (3) the cultural differences in cooperation-competition are related to those in n Affiliation and n Achievement. Results indicate that social motives inferred from a cooperation-competition game have a meaningful relation to those inferred from a projective test, but that the cultural differences in cooperation-competition are larger and are not explained by cultural differences in n Affiliation and n Achievement. Social motives inferred from each measurement methodology, while somewhat related, are distinct.     

Confounding effects of individualism in children's cooperation — Competition social motive measures

The exact nature of cooperation — competition differences among children has remained obscure because the effect of individualistic motivation has important but unanalyzed influence on the frequency of cooperative and competitive responding. In order to clarify the nature of cultural differences in cooperation — competition, a novel social motive game was developed that provides distinct cooperative, competitive, and individualist alternatives. The measure was administered to 120 fourth-through sixth-grade Anglo-American and Mexican-American children of lower- and upper-middle-income levels. Consistent with previous research, Mexican-American children were generally more cooperative than Anglo-American children. Contrary to previous conclusions, however, individualism, not competition, was the strongest social motive among children, and Anglo-American children were generally more individualistic but not generally more competitive than Mexican-American children. Culture findings challenge both the methods and the results of previous cooperation — competition studies.The present research was partially supported by a University of California Intramural Research Grant No. 5-538404-19900-5. The authors are grateful to Jan Allison, Allen Binegar, and Robert Green for their assistance in the data collection.     

ACQUISITION OF EXPRESSIVE SIGNING BY AUTISTIC CHILDREN: AN EVALUATION OF THE RELATIVE EFFECTS OF SIMULTANEOUS COMMUNICATION AND SIGN-ALONE TRAINING

Two methods of training autistic children to use manual signs were compared. Two children, one mute and one capable of some verbal imitation, were taught to use signs as expressive labels for pictures of objects. Using an alternating treatments design, speed of sign acquisition was compared across two training conditions in which signs were presented either accompanied by, or without, the corresponding verbal label. In both conditions, the training procedure incorporated reinforcement, modeling, prompting, fading, and stimulus rotation. The efficacy of training in both treatment conditions was demonstrated by the use of a multiple baseline control across signs, but no clear differences in acquisition speed across conditions were apparent. Posttests conducted to assess stimulus control of signing, and learning of verbal labels when these were present in training, showed that the behavior of the imitative, but not the mute, child was controlled by the verbal stimuli. The implications of the results both for understanding deficits characteristic of autistic children and for developing appropriate language training procedures are discussed.     

HENRY THOREAU, NATURE, AND AMERICAN DEMOCRACY

In a famous passage from "Slavery In Massachusetts," Thoreau writes, "The remembrance of my country spoils my walk. My thoughts are murder to the State, and involuntarily go plotting against her."¹ Here is Thoreau the anarchist, the misanthrope, the self-righteous angry young man, as he is so often portrayed in the secondary literature. It would be easy to consider the issue resolved: the conventional wisdom about Thoreau's misanthropy and anarchism are demonstrated, and there is little more to say. It would also be a significant mistake—one that has been made over and over again by commentators on both his political views and his nature writings. Thoreau's comment is not the climax of "Slavery in Massachusetts," but rather is the prelude to the climax. Consider the passage that follows and leads to the conclusion of the essay: