Arousal, working memory, and conscious awareness in contingency learning

There are wide individual differences in the ability to detect a stimulus contingency embedded in a complex paradigm. The present study used a cognitive masking paradigm to better understand individual differences related to contingency learning. Participants were assessed on measures of electrodermal arousal and on working memory capacity before engaging in the contingency learning task. Contingency awareness was assessed both by trial-by-trial verbal reports obtained during the task and by a short post-task recognition questionnaire. Participants who became aware had fewer non-specific skin conductance responses and tended to score higher on a digit span assessment. Skin conductance level was not significantly lower in the aware group than in the unaware group. These findings are consistent with studies showing that lower arousal and greater cognitive processing capacity facilitate conscious perception of a greater breadth of information within a scene or a task.     

The driver vigilance telemetric control system (DVTCS): Investigating sensitivity to experimentally induced sleep loss and fatigue

Vigilance technologies are used in the Australian rail industry to address the risks associated with driver sleepiness and fatigue. The aim of this study was to investigate whether a new device, designed to detect lowered states of arousal using electrodermal activity (EDA), would be sensitive to experimentally induced sleepiness and fatigue. Fifteen individuals (7 of them female, 9 male; 18–32 years of age) spent 3 consecutive days in the laboratory, which included 1 night of sustained wakefulness (28 h). The participants completed a 10-min psychomotor vigilance task (PVT) and fatigue and sleepiness ratings every 2 h, and a 30-min driving simulator every 4 h. As was expected, simulated driving, PVT, and subjective ratings indicated increasing levels of sleepiness and fatigue during sustained wakefulness. The EDA device output did not coincide with these findings. The results indicated that the EDA indicator was not sensitive to increased sleepiness and fatigue at the levels produced in the present study.     

The Role of Rumination in Predicting Seasonality

The impact of the changing seasons on mood and behavior (i.e., seasonality) has long been of interest to researchers. Recently, researchers have begun to look beyond biological explanations to investigate psychological variables that may play a role in the development of seasonal affective disorder (SAD) and subsyndromal (S-SAD) levels of seasonality. Rumination, in particular, has received initial support as a process that predicts more severe levels of winter depression. In the first study, we assessed the effects of rumination, current weather conditions, current level of depression, and attitudes toward weather conditions as predictors of seasonality. In addition to weather conditions, weather attitudes, and current depression, rumination emerged as a significant predictor of seasonality in females but not for males. In the second study, we followed individuals categorized as being high (S-SAD) and low in seasonality over time and assessed for depression at Time 1 and Time 2. Rumination, in addition to current weather conditions and weather attitudes, emerged as a significant predictor of depression for females in the S-SAD group. The results of these studies provide support for the role of rumination in seasonal depression, particularly for females. This type of research may contribute to attempts to better explain gender differences in seasonal depression.     

Cognitive-behavioural therapy for adolescents with bulimic symptomatology: The acceptability and effectiveness of internet-based delivery

Background

The evidence base for the treatment of adolescents with bulimia nervosa (BN) is limited.

Aims

To assess the feasibility, acceptability, and clinical outcomes of a web-based cognitive-behavioural (CBT) intervention for adolescents with bulimic symptomatology.

Method

101 participants were recruited from eating disorders clinics or from beat, a UK-wide eating disorders charity. The programme consisted of online CBT sessions (‘Overcoming Bulimia Online’), peer support via message boards, and email support from a clinician. Participants' bulimic symptomatology and service utilisation were assessed by interview at baseline and at three and six months. Participants' views of the treatment package were also determined.

Results

There were significant improvements in eating disorder symptoms and service contacts from baseline to three months, which were maintained at six months. Participants' views of the intervention were positive.

Conclusions

The intervention has the potential for use as a first step in the treatment of adolescents with bulimic symptomatology.     

Training redundant artificial neural networks: Imposing biology on technology

One biological principle that is often overlooked in the design of artificial neural networks (ANNs) is redundancy. Redundancy is the replication of processes within the brain. This paper examines the effects of redundancy on learning in ANNs when given either a function-approximation task or a pattern-classification task. The function-approximation task simulated a robotic arm reaching toward an object in two-dimensional space, and the pattern-classification task was detecting parity. Results indicated that redundant ANNs learned the pattern-classification problem much faster, and converge on a solution 100% of the time, whereas standard ANNs sometimes failed to learn the problem. Furthermore, when overall network error is considered, redundant ANNs were significantly more accurate than standard ANNs in performing the function-approximation task. These results are discussed in terms of the relevance of redundancy to the performance of ANNs in general, and the relevance of redundancy in biological systems in particular.     

Measurement of directional lever response reaction time with the Commodore 64

Routines are described for timing directional lever responses with the Commodore 64 micro-computer. Millisecond reaction timing is carried out with on-board hardware clocks, and lever responses are detected by monitoring the position of a joystick interfaced to a controller port. In a demonstration program, a machine code subroutine is used to measure the reaction times of lever responses in a spatial relations task. In addition, modifications to the demonstration program are suggested to adapt it for use with other tasks.     

Concurrent and predictive electrodermal correlates of symptomatology in recent-onset schizophrenic patients.

Electrodermal activity and symptomatology were interrelated in a group of 56 male and 13 female recent-onset schizophrenic patients. Electrodermal activity was indexed by the frequency of nonspecific skin conductances responses and the number of trials to habituation of the skin conductance orienting response. Symptomatology was assessed by the Brief Psychiatric Rating Scale (BPRS) on two separate test occasions. The first test occasion was during the inpatient period when psychotic symptoms were prevalent and medications were variable. The second test occasion was several months later during an outpatient period when symptoms were stabilized and medications held constant. Electrodermal activity was positively and significantly related to a number of symptoms in male patients, most reliably the BPRS factors Activation and Hostility/Suspiciousness. These relationships were most consistent during the outpatient period. Of particular theoretical interest, greater electrodermal activity during the inpatient period was associated with greater outpatient psychopathology. The results suggest that heightened inpatient electrodermal activity is predictive of poor short-term symptomatic recovery in recent-onset, acute, male schizophrenic patients.     

Lateral asymmetries in electrodermal responses to nonattended stimuli: a reply to Walker and Ceci

Walker and Ceci (1983) pose a number of interesting and potentially important criticisms and alternative explanations regarding the laterality finding and hypothesis of Dawson and Schell (1982). The present evaluation finds each of the criticisms and alternative explanations to be inadequate. We then distinguish between two alternative interpretations of the Dawson and Schell hypothesis, one based on inherent functional properties of the two hemispheres and the other based on the notion that each hemisphere is a partially independent pool of processing resources. Walker and Ceci's fundamental objection seems to apply only to the first interpretation.     

Scaling of apparent accentedness by magnitude estimation and sensory modality matching

In each of three experiments, 24 students judged the accentedness present in the speech of eight Spanish-English bilinguals.Ss gave magnitude estimations and also squeezed a hand dynamometer to indicate the amount of accentedness in the reading of an English passage by each of the speakers. There was significant agreement amongSs regarding the speech samples with each scaling method, and interscale agreement was good. Power functions fitted to the data had exponents falling in the range expected from earlier psychophysical studies. Scale values correlated significantly with the frequency of accented pronunciations by the speakers as judged by two independent judges. The use of these scaling methods for future research on linguistic features of accent and on the relation between accent and language attitudes is discussed.