Stress, reactivity, and immune function in healthy men.

We examined the effects of acute psychological stress on lymphocyte proliferation and circulating levels of interleukin-1 and -2. Healthy men were exposed to two viewings of a gruesome surgery film and were asked to recall details of the film twice during a 30-min period. These subjects were compared to a nonstress control group. Lymphocyte proliferation to the mitogen concanavalin A (Con A; 5 micrograms/ml) was decreased during and after exposure to the stressor when compared to the control group. This decrease was more pronounced in subjects exhibiting greater blood pressure reactivity while viewing the film than in subjects showing smaller blood pressure responses. None of the other immunological measures was significantly affected by the stressor. Cortisol was not correlated with lymphocyte responsiveness. Possible explanations for these results and implications for further research are discussed.     

Investigations of the reinstatement of extinguished fear

In two experiments, fear was conditioned to the situational cues in one compartment of a hurdle-jumping apparatus and was then extinguished. Subsequently, either one shock (Experiment 1) or three or nine shocks (Experiment 2) were given in a situation distinctively different from that in which conditioning and extinction had taken place. Although some associative strength between the situational cues and fear was shown to have remained after extinction, in neither experiment did the postextinction-shock treatment increase the fear elicited by these cues: Escape-from-fear performance was no better in the shocked groups than in control groups given no additional shock. Thus, the nonassociative hypothesis which postulates that inflating the value of the representation of the UCS with shock-alone presentations can reinstate the extinguished fear of a stimulus was not supported. Rather, the results showed that, after extinction, an increase in fear of a simulus depended on further conditioning to that stimulus. The data also indicated that the nonvisual components of the situational cues predominated over the visual component.     

Empirical tests of scientific realism: A quantitative framework

The scientific realism debate in philosophy of science raises some intriguing methodological issues. Scientific realism posits a link between a scientific theory's observational and referential success. This opens the possibility of testing the thesis empirically, by searching for evidence of such a link in the record of theories put forward in the history of science. Many realist philosophers working today propose case study methodology as a way of carrying out such a test. This article argues that a qualitative method such as case study methodology is not adequate for this purpose, for two reasons: to test scientific realism is to pose an effects-of-causes question, and observational and referential success are quantities that theories possess to a greater or lesser degree. The article concludes that an empirical test of scientific realism requires a quantitative method.     

Scientific realism and the criteria for theory-choice

The central terms of certain theories which were valued highly in the past, such as the phlogiston theory, are now believed by realists not to refer. Laudan and others have claimed that, in the light of the existence of such theories, scientific realism is untenable. This paper argues in response that realism is consistent with — and indeed is able to explain — such theories' having been highly valued and yet not being close to the truth. It follows that the set of highly-valued past theories cited by Laudan, presumed to militate against realism, is in fact innocuous to the doctrine. The argument hinges largely on identifying the grounds on which theory-adoption is actually performed.     

Effects of Eyewitness Evidence on Plea-Bargain Decisions by Prosecutors and Defense Attorneys1

The present experiment tested the relative impact of two types of eyewitness evidence (identification and non identification) on plea-bargain decisions by prosecutors and defense attorneys. A hypothetical case involving a robbery was mailed to three prosecutors and three defense attorneys in each of 47 states. The subjects were randomly assigned to receive a case in which an eyewitness claimed: (a) the defendant was the criminal (identification), (b) the defendant was not the criminal (non identification), or (c) it was not possible to tell whether the defendant was the criminal (control). Similar to findings with jurors, both prosecutors and defense attorneys underutilized the non identification information in making their plea-bargain decisions. In the case of the prosecutors, there was evidence that the underutilization of eyewitness non identification was at least partially mediated by the prosecutors' predictions of juror reaction to the evidence.     

Final part-word repetitions in school-age children: two case studies

In contrast to the many published accounts of the disfluent repetition of sounds at the beginnings of words, cases where it is predominantly the final parts of words that are repeated have been reported relatively rarely. With few exceptions, those studies that have been published have described either pre-school children or neurologically impaired subjects. The purpose of this case report was to describe final part-word repetitions in the speech of two school-age boys of normal intelligence with no known neurological lesions. Their speech was recorded during spontaneous conversation, reading, and sentence repetition. The repetitions occurred in all three speaking conditions, although the majority of instances were observed in spontaneous speech, and on both content words and function words. The participants exhibited no apparent awareness of the disfluencies, no abnormal muscle tension, and no accessory behaviours. Each child produced word-final repeated fragments whose phonological structure was highly predictable according to his individual set of rules. The results are discussed in terms of possible motor and cognitive explanations for the disfluencies. EDUCATIONAL OBJECTIVES: As a result of this activity, the participant will be able to: (1) summarize prior research into final part-word repetition; (2) describe the detailed characteristics of final part-word repetitions as displayed by two children of normal intelligence; and (3) discuss ways in which the behaviour might be explained as part of a model of speech production.     

Right-hemispheric cortical contributions to language ability in healthy adults

In this study we investigated the correlation between individual linguistic ability based on performance levels and their engagement of typical and atypical language areas in the brain. Eighteen healthy subjects between 21 and 64 years participated in language ability tests, and subsequent functional MRI scans measuring brain activity in response to a sentence completion and a word fluency task. Performance in both reading and high-level language tests correlated positively with increased right-hemispheric activation in the inferior frontal gyrus (specifically Brodmann area 47), the dorsolateral prefrontal cortex (DLPFC), and the medial temporal gyrus (Brodmann area 21). In contrast, we found a negative correlation between performance and left-hemispheric DLPFC activation.Our findings indicate that the right lateral frontal and right temporal regions positively modulate aspects of language ability.     

Bias in Eyewitness Accounts: The Effects of Question Format,Delay Interval,and Stimulus Presentation

One of three representations of a staged automobile collision was shown to 180 students from introductory psychology classes. We then questioned the students about details of the accident, using either marked or unmarked modifiers. Half the students were questioned immediately after viewing the stimulus material and half after a 20-min delay. The results indicated that estimates of the magnitude of a number of aspects of the collision were significantly greater when unmarked modifiers were used in phrasing the relevant questions. Students who were questioned after the 20-min delay gave significantly greater estimates of monetary damage than the students who answered immediately after viewing the representation. The nature of the stimulus material had inconsistent but significant effects.