Contributing to Discourse

For people to contribute to discourse, they must do more than utter the right sentence at the right time. The basic requirement is that they add to their common ground in an orderly way. To do this, we argue, they try to establish for each utterance the mutual belief that the addressees have understood what the speaker meant well enough for current purposes. This is accomplished by the collective actions of the current contributor and his or her partners, and these result in units of conversation called contributions. We present a model of contributions and show how it accounts for a variety of features of everyday conversations.     

Task sets under reconstruction: effects of partially incorrect precues.

To perform a task that differs from a previously performed one, it is necessary to prepare for the new task as well as to disable the task set of the preceding task. In a series of three experiments we examined whether preparation for a task shift implies a direct update of the task set that is carried over from the preceding trial. To this end, in Experiments 1 and 2 we factorially varied the relation of the task in trial n, first, to the task in trial n - 1 (intertask relation) and, second, to the task that was precued for trial n (precue-to-task relation). Invalid precues resulted in substantial costs, which increased with longer precueing intervals. However, this increasing effect of the precue-to-task relation was not accompanied by a decreasing effect of the intertask relation. Furthermore, both effects had different qualitative properties. These findings suggest that two tasks can be represented concurrently but on two different levels of representation. In Experiment 3 we observed that the persistence of the effect of the intertask relation depends on the possibility that task repetitions can occur in trials in which a task shift is precued. This suggests that the persistence of the effect of the intertask relation is controlled in a context-sensitive way.     

Statistical inference based on latent ability estimates

The quality of approximations to first and second order moments (e.g., statistics like means, variances, regression coefficients) based on latent ability estimates is being discussed. The ability estimates are obtained using either the Rasch, or the two-parameter logistic model. Straightforward use of such statistics to make inferences with respect to true latent ability is not recommended, unless we account for the fact that the basic quantities are estimates. In this paper true score theory is used to account for the latter; the counterpart of observed/true score being estimated/true latent ability. It is shown that statistics based on the true score theory are virtually unbiased if the number of items presented to each examinee is larger than fifteen. Three types of estimators are compared: maximum likelihood, weighted maximum likelihood, and Bayes modal. Furthermore, the (dis)advantages of the true score method and direct modeling of latent ability is discussed.     

Humor As a Stress Moderator in the Prediction of Blood Pressure Obtained during Five Stressful Tasks

In five consecutive stressful tasks we examined the role of humor as a potential stress moderator using systolic and diastolic blood pressure as an indication of cardiovascular reactivity. In all five tasks, the Coping Humor Scale interacted with sex in the prediction of blood pressure. The same pattern was found in response to each of the five tasks: Females who were higher in coping humor exhibited lower systolic blood pressure than females scoring lower on coping humor, while the reverse characterized males; males who scored high on the coping humor scale exhibited higher systolic blood pressure than males scoring low on that scale. Similar though less robust results were found when the Situational Humor Response Questionnaire was used as the measure of humor. In the Cold Pressor Task, which involves pain and endurance, interactions were found between humor, sex, and trials indicating a stress-moderator effect. The absence of interactions indicating stress moderation in most of the analyses with the other four stress tasks suggests that humor may play more of a role in moderating the impact of uncontrollable and passively experienced stressors. Tasks requiring more active, problem-solving behavior may be less amenable to the beneficial effects of humor. The findings do not clearly resolve the questions about the role of humor in effecting responses to stress. However, they do suggest that the subjects' sex may be an important consideration when evaluating the impact of humor as a stress moderator.     

Uses of hypnosis in evaluating malingering and deception

Hypnosis, as a method of detecting deception, is examined with respect to its forensic applications. The degree of hypnotizability and whether formal hypnotic procedures may be employed are discussed with both the relevant clinical and legal issues in mind. Finally, the use of hypnosis in determining the authenticity of psychosomatic conditions is addressed.     

Reinforcement from the sucking environment and subsequent modification of sucking behavior in the human neonate

The reinforcing aspects of sucking behavior in 36 human newborns was examined in a limited instrumental conditioning paradigm where sucking was both operant and reinforcer. During training, response density (rate based on sucking opportunity time) and latency were measures of two components of nonnutritive sucking, contingent negative pressure suction, and incidental jaw movement. The strategy for determining the reinforcing aspects of sucking involved comparisons of three types of sucking stimuli as reinforcers. The nature of modified operant sucking was investigated during extinction by examining number of sucks per burst, number of bursts emitted, and interburst interval time. The feedback from sucking which acted as reinforcement was concluded to be response density. Sucking was modified by changes in pausing behavior, including response latency and pauses between bursts of sucks. The number of sucks per burst also showed a significant change under certain conditioning arrangements.     

On the relation between visual surround and motion aftereffect velocity

Two experiments examined the effect of changes in the visual surround upon the velocity of motion aftereffects. Experiment I showed that introduction or reintroduction of a patterned surround midway through the test period was sufficient to produce an increase in apparent velocity. However, a greater increase was observed when a patterned surround instead of a dark homogeneous surround had been used during the induction period. Experiment II demonstrated that luminance change was also sufficient to produce an increase in apparent velocity, although the extent of the increase was not as great as that produced through the use of the patterned surround in Experiment I. These results indicate that a change in stimulus surround is sufficient to produce an increase in the velocity of a motion aftereffect and that the extent of the increase is dependent upon the characteristics of both the induction and test surrounds.     

On the process of comparing sentences against pictures

The present study outlines a theory of how people compare sentences against pictures. This theory was tested in four experiments in which Ss were timed as they judged whether a sentence (e.g., Star isn't above plus) was true or false of a picture (e.g., ⁺_∗). The latencies in these tasks were consistent with the thesis that: (1) sentences are represented in terms of elementary propositions; (2) pictures are encoded in the same interpretive format; (3) these two codes are compared in an algorithmic series of mental operations, each of which contributes additively to the response latency; and (4) sentence encoding, picture encoding, comparing, and responding are four serially ordered stages, and their component latencies are additive. From these results, it was also possible to rule out certain explanations based on visual imagery, conversion (e.g., converting isn't above into is below), reading time, normative word frequencies, and other factors. Finally, it was shown that this theory is consistent with previous studies on sentence comprehension, sentence verification, concept verification, and other related phenomena.     

A comparative analysis of two community stressors' long-term mental health effects

The investigation directly compared the long-term mental health consequences of two community-wide stressors, the Three Mile Island (TMI) nuclear accident and widespread unemployment due to layoff, in demographically comparable samples of women. Results showed a marked degree of similarity in the stressors' effects: Levels of subclinical symptomatology were elevated to similar degrees in each sample during the year following stressor onset, and symptom levels remained elevated in each sample 2 to 3 1/2 years later. Moreover, variables identified as predictors of enduring psychological distress were virtually identical for the two samples. Additional analyses revealed that the mental health status of unemployed husbands mediated the negative psychological effects of layoff on their wives. Implications of these results for understanding the long-term consequences of exposure to community-wide stress are discussed.