Partition-edit-count: naive extensional reasoning in judgment of conditional probability

The authors provide evidence that people typically evaluate conditional probabilities by subjectively partitioning the sample space into n interchangeable events, editing out events that can be eliminated on the basis of conditioning information, counting remaining events, then reporting probabilities as a ratio of the number of focal to total events. Participants' responses to conditional probability problems were influenced by irrelevant information (Study 1), small variations in problem wording (Study 2), and grouping of events (Study 3), as predicted by the partition-edit-count model. Informal protocol analysis also supports the authors' interpretation. A 4th study extends this account from situations where events are treated as interchangeable (chance and ignorance) to situations where participants have information they can use to distinguish among events (uncertainty).     

Size of the neocerebellar vermis is associated with cognition in healthy elderly men

Cerebellar volumes show small positive correlations with cognitive ability in young adults, but no studies have examined this relationship in older adults. Furthermore, no studies have examined relationships between sizes of subareas of the cerebellum and cognitive ability. We hypothesized that size of the two areas of the neocerebellar vermis would correlate with a battery of eight cognitive tests in 50 men aged 65-70. Size of the neocerebellar areas of the vermis correlated positively with several cognitive tests (r's=.29-.37, p<.05), whilst sizes of other parts of the vermis did not correlate with any cognitive tests. Total cerebellar volumes correlated significantly with a test of nonverbal reasoning (r=.030, p=.42). These findings suggest a specific association of neocerebellar vermis size with variations in cognitive ability in older adults.     

A new breed of computer users: Rats control a cursor via joystick manipulation

Many exciting findings have been reported in the 15 years since monkeys were first demonstrated to have the capacity to perform computerized tasks. The present data indicate that albino rats can also learn to respond to computer-generated stimuli by manipulating a joystick. Although the rat’s control of the cursor is not as skillful as has been reported for primate species, it is clearly better than chance and suggests the great potential for comparative investigation afforded by use of the computer test system.     

The relationship between interpersonal perception and post-traumatic stress disorder-related functional impairment: a social relations model analysis

This study used Kenny's social relations model to examine the relationship between Post-Traumatic Stress Disorder-related impairment and interpersonal perceptions. Participants were 124 students who had previously completed the Post-traumatic Stress Diagnostic Scale as part of a larger study. After engaging in brief dyadic conversations with 3 other students, participants recorded perceptions of personality traits for themselves, their interaction partners and how they believed their partners saw them (metaperceptions). Results indicated that those with more severe post-traumatic stress disorder-related impairment saw themselves negatively and believed their interaction partners also viewed them negatively. However, these individuals were not seen differently by others, except that they were rated as less dependable. Our findings suggest that post-traumatic stress disorder is associated with negative beliefs about the self that may influence self-esteem and interpersonal relationships.     

Developing a treatment manual for attention management in chronic pain

This article reports the development of a protocol for the therapeutic application of "attention control" for chronic pain. Attention control is the limitation of the impact of pain by switching or retunning attention. An expert systems approach was used to develop the protocol. In the first stage an extensive literature search retrieved published and unpublished accounts of attention control strategies and a draft treatment manual was prepared. In the second stage 6 experts were recruited and they independently read and reviewed the draft manual. They were interviewed using a semi-structured protocol to elicit their views on the draft manual. The manual was then revised to accommodate the information and expertise. In addition to providing expert opinion on the manual the experts also raised issues about the process of change in psychological treatment for chronic pain. These issues were organized into a process model of change in chronic pain.     

Context-processing deficits in schizophrenia: diagnostic specificity, 4-week course,and relationships to clinical symptoms

Previous research on schizophrenia suggests that context-processing disturbances are one of the core cognitive deficits present in schizophia. However, it is not clear whether such deficits are specific to schizophrenia as compared with other psychotic disorders. To address this question, the authors administered a version of the AX Continuous Performance Test designed to assess context processing in a sample of healthy controls, patients with schizophrenia, and patients with other psychotic disorders. Participants were tested at index (when medication naive and experiencing their first contact with psychiatric services) and 4 weeks later, following medication treatment. At index, patients with schizophrenia and the psychotic comparison group demonstrated similar impairments in context processing. However, context-processing deficits improved in the psychotic comparison group at 4 weeks but did not improve in patients with schizophrenia.     

Do age of onset and course of illness define biologically distinct groups within atypical depression?

Illness course separates patients with atypical depression into tricyclic responders and nonresponders as does perceptual asymmetry. The authors therefore investigated whether the course-of-illness parameters would define groups within atypical depression differing in brain laterality. Patients with atypical depression were assessed for illness course and brain laterality. Two patient groups were defined, 1 with onset prior to age 20 plus a very chronic course, and a 2nd group having later onset or less chronic illness. Patients reporting early onset of very chronic dysphoria showed significantly less right-ear (left-hemisphere) accuracy and also differed in characteristic perceptual asymmetry when compared to patients with later onset or less chronicity. Course of illness may usefully define more homogeneous depressive subgroups within atypical depression.     

Flanker and negative flanker effects in letter identification

In a speeded choice reaction time task, responses to centrally presented letter targets can be altered by the identity of surrounding task-irrelevant letters (flankers). In the standard flanker effect, flankers associated with the same response as the target lead to faster and more accurate responses, whereas flankers associated with a different response lead to slower and more error-prone responses. B. A. Eriksen and C. W. Eriksen (1974, pp. 143-149) have argued that these flanker effects occur through response competition. We present data from a novel version of the Eriksen task, in which some targets and flankers consist of letter forms that are morphed versions of target letters. In this paradigm, flankers induce classic flanker effects on well-formed targets. But flankers induce an opposite effect, termed a negative flanker effect on morphed letter targets. For example, targets that are morphs between the letters "A" and "H" are more likely to be identified as an "A" when flanked by an "H." The interpretation advanced here is that there are two distinct kinds of flanker effects contrast enhancement in perceptual processes and response competition in response selection processes.     

authors index

Authors Index

authors index     

Stress symptoms of two groups before and after the terrorist attacks of 9/11/01

This study investigated stress symptoms before and after the September 11, 2001 terrorist attack on the World Trade Center. Responses to the Smith Stress Symptoms Inventory were compared for Chicago area college students assessed 1 to 5 weeks after 9/11 (n=149) and a comparable sample tested up to 5 months prior to 9/11 (n=320). Post-9/11 participants scored higher on Attention Deficit. Contrary to prior research, post-9/11 participants did not score higher on distress, including Worry, Autonomic Arousal/Anxiety, Striated Muscle Tension, Depression, and Anger. It is suggested that those indirectly exposed to a terrorist attack may display traditional symptoms of distress and arousal (as suggested by previous research). Later symptoms of attention deficit and distancing may emerge. This work was based on independent pre- and post-9/11 samples and must be replicated longitudinally as a test-retest to draw conclusions regarding change over time.