Individual differences in stress and fatigue in two field studies of driving

This paper reports the findings of two field studies of Australian drivers in which individual differences in stress and fatigue were investigated. In the first study, 58 professional drivers completed measures of mood, fatigue and other subjective stress state measures, before and after performing a prolonged driving trip. The results indicated that the scales were sensitive to increased fatigue following the driving trip, and correlated appropriately with Fatigue Proneness, a driver stress trait. In the second study, 104 non-professional drivers completed identical subjective stress state measures as the professional drivers, before and after performing a driving trip. Drivers completed a measure of driving-related stress traits, the Driver Stress Inventory (DSI), and a measure of coping, the Driving Coping Questionnaire (DCQ). Both measures were predictive of state response to driving, and the association between Fatigue Proneness and post-drive fatigue found in the first study was replicated. Findings from these studies suggest that fatigue and stress reactions to driving are psychometrically distinct, but may have some common antecedents, such as use of emotion-focused coping. The studies confirm the importance of fatigue and stress as potential safety problems, but also highlight the role of individual differences in response to the demands of driving.     

Internet-delivered assessment and manipulation of anxiety-linked attentional bias: Validation of a free-access attentional probe software package

It recently has been established within the laboratory that the attentional probe methodology not only can sensitively assess the threat attentional bias associated with anxiety vulnerability, but also can be configured to yield training tasks capable of modifying emotional vulnerability by manipulating such attentional selectivity. In order to appraise and exploit the potential practical applications of such procedures, it is desirable that clinical investigators without specialist equipment should become able to deliver such tasks within field settings. The present research program involved development of a fully customizable attentional probe software package, that delivers assessment and training versions of the probe task across the Internet. Two experimental studies served to validate the assessment and training efficacy of resulting probe task variants, completed remotely by GAD sufferers and nonclinical populations using their own computers. We advise fellow researchers how to freely download this software package for use within their own investigations.     

Skinner boxes for psychotics: operant conditioning at Metropolitan State Hospital

Between 1953 and 1965, Ogden Lindsley and his associates conducted free-operant research with psychiatric inpatients and normal volunteers at Metropolitan State Hospital in Waltham, Massachusetts. Their project, originally named "Studies in Behavior Therapy," was renamed "Harvard Medical School Behavior Research Laboratory" in 1955. This name change and its implications were significant. The role of the laboratory in the history of the relationship between the experimental analysis of behavior and applied behavior analysis is discussed. A case is made for viewing Lindsley's early work as foundational for the subfield of the experimental analysis of human behavior that formally coalesced in the early 1980s. The laboratory's work is also contextualized with reference to the psychopharmacological revolution of the 1950s. Finally, a four-stage framework for studying the historical and conceptual development of behavior analysis is proposed.     

Enhancement of phonological memory following transcranial magnetic stimulation (TMS)

Phonologically similar items (mell, rell, gell) are more difficult to remember than dissimilar items (shen, floy, stap), likely because of mutual interference of the items in the phonological store. Low-frequency transcranial magnetic stimulation (TMS), guided by functional magnetic resonance imaging (fMRI) was used to disrupt this phonological confusion by stimulation of the left inferior parietal (LIP) lobule. Subjects received TMS or placebo stimulation while remembering sets of phonologically similar or dissimilar pseudo-words. Consistent with behavioral performance of patients with neurological damage, memory for phonologically similar, but not dissimilar, items was enhanced following TMS relative to placebo stimulation. Stimulation of a control region of the brain did not produce any changes in memory performance. These results provide new insights into how the brain processes verbal information by establishing the necessity of the inferior parietal region for optimal phonological storage. A mechanism is proposed for how TMS reduces phonological confusion and leads to facilitation of phonological memory.     

Reading disability and hemispheric interaction on a lexical decision task

The assumptions tested were that the relative contribution of each hemisphere to reading alters with experience and that experience increases suppression of the simultaneous use of identical strategies by the non-dominant hemisphere. Males that were reading disabled and phonologically impaired, reading disabled and phonologically normal, or with no reading disability were presented familiar words, orthographically correct pseudowords, and orthographically incorrect non-words for lexical decision. Accuracy and response times in all groups showed a shift from no asymmetry in processing non-words to a stable left hemisphere advantage and clear suppression of the right hemisphere in processing words. In the pseudoword condition, accuracy scores were higher when both hemispheres were free to engage, especially in those with a reading disability and responses slowed in the phonologically impaired group but not the phonologically normal groups when the right hemisphere was disengaged. As familiar words typically invoke lexical processing by both hemispheres while pseudowords invoke lexical processing by the right and non-lexical processing by the left hemisphere, and as non-lexical processing is weak in the phonologically impaired, the results support the assumptions that were tested.     

Selective attention and emotional vulnerability: assessing the causal basis of their association through the experimental manipulation of attentional bias

Although it is well-established that vulnerability to negative emotion is associated with attentional bias toward aversive information, the causal basis of this association remains undetermined. Two studies addressed this issue by experimentally inducing differential attentional responses to emotional stimuli using a modified dot probe task, and then examining the impact of such attentional manipulation on subsequent emotional vulnerability. The results supported the hypothesis that the induction of attentional bias should serve to modify emotional vulnerability, as revealed by participants' emotional reactions to a final standardized stress task. These findings provide a sound empirical basis for the previously speculative proposal that attentional bias can causally mediate emotional vulnerability, and they suggest the possibility that cognitive-experimental procedures designed to modify selective information processing may have potential therapeutic value.     

Aging effects on memory encoding in the frontal lobes

Functional magnetic resonance imaging (fMRI) was used to compare frontal-lobe activation in younger and older adults during encoding of words into memory. Participants made semantic or nonsemantic judgments about words. Younger adults exhibited greater activation for semantic relative to nonsemantic judgments in several regions, with the largest activation in the left inferior frontal gyrus. Older adults exhibited greater activation for semantic judgments in the same regions. but the extent of activation was reduced in left prefrontal regions. In older adults, there was a significant association between behavioral tests of declarative and working memory and extent of frontal activation. These results suggest that age-associated decreases in memory ability may be due to decreased frontal-lobe contributions to the initial encoding of experience.     

The prediction of violent and nonviolent criminal behavior in a methadone maintenance population

The utility of traits associated with Antisocial Personality Disorder in making risk assessments of violent and nonviolent crimes was examined in 254 subjects sampled from a methadone maintenance population. A factor analysis of a number of baseline measures resulted in five factors measuring hostility, insecure attachment, impaired reality testing, antisocial personality, and empathy. These factors were used in logistic regression analysis to predict charges for violent and nonviolent crimes over a 2-year period. Individuals with high scores on the antisocial personality factor had an increased risk of both violent and nonviolent criminal charges. Individuals with low scores on the empathy factor were at high risk for violent crimes. In an analysis using the factor components rather than the factors, the measures of perspective-taking and a socialization were associated with violent criminal charges, and the measure of psychopathy, but not antisocial behavior, was associated with nonviolent criminal charges. The results support the use of measures of personality traits in addition to measures of a history of antisocial behavior in making violence risk assessments in substance-dependent patients. The DSM construct and diagnosis of Antisocial Personality Disorder may be enhanced by greater emphasis on personality traits associated with antisocial behavior.