Skin conductance responses as predictor of emotional responses to stressful life events

Preferential preattentive processing towards threat has been proposed to play a casual role in the development of anxiety, mainly because it reliably predicts emotional responding to stressful events. However, in the investigation of the predictive value of preferential preattentive processing towards threat, the emotional Stroop task has exclusively being used. This study was designed to prospectively investigate the predictive value of skin conductance reactivity in response to masked (i.e., preattentively perceived) threatening pictures on emotional responding following stressful life events. To collect skin conductance data, the picture perception task was administered to 136 police recruits due to enroll into active duty within 2-4 months. To assess psychological distress following emotionally stressful life events, the impact of event scale were administered approximately 24 months later. Controlling for trait anxiety, analyses indicated that enhanced skin conductance reactivity in response to masked threatening pictures (relative to neutrals) was a strong predictor of emotional responding to stressful life events. This finding support preferential preattentive processing towards threat as a relatively independent factor predictive of emotional responding.     

Conditioned placebo responses

Following earlier animal research, we attempt to condition placebo effects in human subjects. Four groups of 8 voluntary subjects were told that the experimenters would test a powerful new analgesic cream over three sessions by assessing its ability to reduce experimentally induced pain. The analgesic cream was, in fact, a placebo. In the first session all subjects were tested with and without the cream to assess their placebo response. In the second session, to condition two groups (with differing stimulation levels) to experience pain relief in response to the placebo, we repeatedly paired a reduction in nocioceptive stimulation with placebo administration. (Subjects were unaware that stimulation levels were manipulated). To condition the other two groups (with different stimulation levels) to experience an exacerbation of the pain, we paired an increase in nocioceptive stimulation with placebo administration. In the third session, all subjects were again tested for placebo response. Results suggested that placebo responses are conditionable in the laboratory in both a positive and negative direction. The clinical implications of a learning theory of placebo behavior are discussed.     

Rhythms and responses

Rhythms are fundamental to behavior, but the control mechanism for timed responses is not known. Many theorists have assumed that there is a central clock coordinating behavior in all sensory modalities and response modes. We tested this hypothesis using a rhythmic tapping task in which university undergraduates first attempted to synchronize responses with brief auditory, tactile, or visual stimuli and then continued to tap at the same rate on their own. Performance was most variable with visual stimuli and least variable with auditory stimuli. The detailed results suggest that performances are not based on a common clock, but, rather, different strategies are employed when the task is presented in different modalities. We reject the hypothesis of a single timing mechanism as controlling behavior and, in doing so, question the validity of information processing models that are formulated without regard to temporal relations among their conjectured processes.     

Conditioning of counter-empathetic emotional responses

The present research tested the hypothesis that the quality of an observer's vicarious emotional response, as measured by autonomic, expressive, and self-report indexes, is a function of the observer's conditioning history with particular facial expressive displays of emotion. It was predicted that conditions of congruence (Symmetry) between the affective expression of a model and the outcome (shock or reward) presented to an observer would enhance initial empathetic responses, but that conditions of incongruence (Asymmetry) between the model's displays and observer's outcomes would lead to counter-empathetic responses. These changes in the quality of observers' vicarious emotional responses should generalize to a test phase when no rewards or punishments are presented to observers. The results for all measures were consistent and indicate that asymmetric conditioning modified the initial empathetic responses of observers to either counter-empathetic responses or indifference. On the other hand, symmetric conditioning enhanced observers' initial empathetic responses. These effects were evident in the test phase when no reinforcements were administered to the subject. The results are consistent with the theoretical assumption that facial expressions of emotion can acquire meaning and hedonic valence because of their predictive significance and thus can function as conditioned stimuli capable of evoking empathetic and counter-empathetic emotional responses.     

Computer-based assessment of student-constructed responses

Student-constructed responses, such as essays, short-answer questions, and think-aloud protocols, provide a valuable opportunity to gauge student learning outcomes and comprehension strategies. However, given the challenges of grading student-constructed responses, instructors may be hesitant to use them. There have been major advances in the application of natural language processing of student-constructed responses. This literature review focuses on two dimensions that need to be considered when developing new systems. The first is type of response provided by the student-namely, meaning-making responses (e.g., think-aloud protocols, tutorial dialogue) and products of comprehension (e.g., essays, open-ended questions). The second corresponds to considerations of the type of natural language processing systems used and how they are applied to analyze the student responses. We argue that the appropriateness of the assessment protocols is, in part, constrained by the type of response and researchers should use hybrid systems that rely on multiple, convergent natural language algorithms.     

Conceptualizations of responses to stress

The article presents the concepts and methodologies used in a series of studies on responses to stress in different areas of life and in different age and social groups. The studies described include findings of the Bonn Longitudinal Study of Aging and several studies on reactions to stress, e.g. coping with chronic disease and other distressing life situations. The discussion of the empirical findings presented focuses on the concept of ‘response hierarchy’ and its possibilities for examining consistency in reactions to stress across time and different situations. The data presented emphasize the need for a process-centred view on stress and responding to stress in the context of a cognitive theory of personality comprehending the individual and her/his world as an undivisible dynamic unit.     

Fetal programming of stress responses

Epidemiological studies have shown that small size at birth is associated with an increased risk of coronary heart disease and its risk factors, including hypertension and Type 2 diabetes.It is suggested that these observations linking low birthweight with disease result from an imbalance between fetal nutrient demand and supply. This imbalance results in metabolic and endocrine adaptations, which benefit the fetus in the short term by reducing fetal growth and increasing fuel availability, but in the longer term they are maladaptive leading to an increased risk of coronary heart disease. Experimental data in animals and recent human observations have suggested that alterations in the set point of the hypothalamic-pituitary-adrenal axis and sympathoadrenal system are important long-term changes that occur in association with reduced fetal growth. These data suggest that the nature and amplitude of the stress response may be determined by intrauterine factors.     

Dissociation of bimanual responses with the Simon effect: on the nonunitization of bimanual responses

The authors examined whether responses of the 2 hands were completely unitized when participants (N=36) produced bimanual responses to lateralized targets in a Simon-type paradigm. Their primary aim was to investigate whether lateralized stimuli differentially influence the response dynamics of the 2 hands. Simon effects were obtained in reaction time and force components of the bimanual response by the hand on the same side as the lateralized stimulus were more forceful than were those of the other hand. Also, Simon effects were larger when the lateralized target appeared alone than when it was accompanied by a distractor on the other side of the display. Finally, responses of the 2 hands were correlated most strongly when stimulus displays were symmetrical. The authors conclude that bimanual responses are strongly coupled, but not perfectly so.     

The restoration of extinguished avoidance responses

Following extensive signaled shuttlebox avoidance training, Fischer 344 rats were given extinction trials until they reliably stopped responding and, thereafter, they received occasional classical CS-UCS pairings during the course of restoration test trials in which shock was absent. Experiment I demonstrated that the classical contingency was both necessary and sufficient for the complete recovery of such behavior. Experiment II revealed that the degree of recovery was not differentially affected by the frequency of such CS-UCS pairings. However, in Experiment III recovery in the presence of this contingency was shown to depend on the number of previous extinction trials, although even after a large number of such trials, a considerable degree of recovery occurred. These findings demonstrated the central role of the classical CS-UCS contingency in restoring a previously extinguished avoidance response.