Caffeine enhances the physiological response to occupational stress in medical students

Caffeine (3.3 mg/kg) was tested against a placebo in 20 male medical students during periods of low (no exams) versus high (final exams) work stress. On each of 8 test days, heart rate and blood pressure were measured at baseline and over a 40-min postdrug interval; immediately afterward, blood was drawn to test plasma cortisol and serum lipid concentrations. Exams increased heart rate (p less than .005) and systolic blood pressure (p less than .02). Caffeine decreased heart rate (p less than .0001) and increased systolic blood pressure (p less than .005), diastolic blood pressure (p less than .0001), plasma cortisol levels (p less than .01), and serum cholesterol levels (p less than .02). Caffeine effects were additive with those of exams, and together they increased the number of men showing systolic blood pressures in the borderline hypertensive range. Thus, caffeine use during periods of increased occupational stress may enhance the cumulative stress response.     

Defense mechanisms and physiological reactivity to stress

The relation between the use of defense mechanisms and autonomic nervous system reactivity, under conditions of laboratory stress, was studied in 78 men and women. Both diastolic blood pressure (DBP) and skin conductance level (SCL) were monitored during exposure to ten stress tasks; concurrently, the use of three defense mechanisms was assessed by coding Thematic Apperception Test stories. Autonomic reactivity was found to be related to defenses; the nature of that relation differed across the defenses. DBP, typically found to be associated with cognitive work, was higher in those individuals who used more Identification, a defense that requires greater cognitive activity. The use of Projection, on the other hand, was associated with lower DBP. In addition, the use of Identification showed a tendency to be associated with lower SCL.     

Cynical hostility and vulnerability to disease: social support, life stress, and physiological response to conflict

Previous research has indicated that high scores on the Cook and Medley Hostility (Ho) scale are associated with increased risk of coronary heart disease and other illness. Our study attempts to clarify this relationship by providing additional evidence concerning the construct assessed by the Ho scale, examining the level of physiological reactivity during interpersonal conflict in high- and low-Ho groups, and assessing the psychosocial profile associated with this characteristic. Extremely high and low Ho groups were selected from a pool of male undergraduates. Consistent with previous findings, high-Ho participants reported greater anger proneness and a more cynical, disparaging view of others than did low-Ho participants. The high-Ho group also tended to be more hostile and less friendly during role-played interactions involving high and low levels of interpersonal conflict, respectively. High-Ho persons also displayed greater diastolic blood pressure reactivity during interpersonal conflict. Finally, the high-Ho group reported less social support and more negative life events and daily irritants then did the low-Ho group. These results support the interpretation of the Ho scale as a measure of cynical hostility and are consistent with the hypothesis that it is related to disease by way of excessive physiological reactivity and a generally stressful, unsupportive social network.     

Alcohol-related motivational tendencies in hazardous drinkers: assessing implicit response tendencies using the modified-IAT

This study examined the utility of an implicit measure of cognitive associations, the Implicit Association Test (IAT; ), to assess alcohol-related approach dispositions. Forty-seven hazardous drinkers completed a modified IAT procedure that assessed the relation between alcohol and behavioral categories (i.e., approach and avoid). Participants completed a series of individual difference measures before an alcohol cue exposure task in which they anticipated alcohol consumption. Results indicate that the modified IAT is associated with binge drinking episodes, perceived difficulty controlling alcohol use, and appetitive responses to alcohol cues. Findings are discussed in terms of the potential value of this measure to assess alcohol-related memory associations among those whose alcohol use puts them at risk for harm.     

Sleep and the affective response to stress and pain.

OBJECTIVE: The current study examined sleep disturbance (i.e., sleep duration, sleep quality) as a correlate of stress reactivity and pain reactivity. DESIGN AND OUTCOME MEASURES: An ecological momentary assessment design was used to evaluate the psychosocial functioning of men and women with fibromyalgia or rheumatoid arthritis (N=49). Participants recorded numeric ratings of pain, the occurrence of a stressful event, as well as positive and negative affect 7 times throughout the day for 2 consecutive days. In addition, participants reported on their sleep duration and sleep quality each morning. RESULTS: Sleep disruption was not found to be an independent predictor of affect. However, sleep was found to buffer the relationship between stress and negative affect and the relationship between pain and both positive and negative affect. CONCLUSION: These results are consistent with a model in which good-quality sleep acts as a biobehavioral resource that minimizes allostatic load.     

Psychopathy and physiological response to emotionally evocative sounds

Despite considerable evidence that psychopathic criminals are deviant in their emotional reactions, few studies have examined responses to both pleasurable and aversive stimuli or assessed the role of different facets of psychopathy in affective deviations. This study investigated physiological reactions to emotional sounds in prisoners selected according to scores on the 2 factors of Hare's Psychopathy Checklist--Revised (PCL-R; R. D. Hare, 1991). Offenders high on the PCL-R emotional-interpersonal factor, regardless of scores on the social deviance factor, showed diminished skin conductance responses to both pleasant and unpleasant sounds, suggesting a deficit in the action mobilization component of emotional response. Offenders who scored high only on the social deviance factor showed a delay in heart rate differentiation between affective and neutral sounds. These findings indicate abnormal reactivity to both positive and negative emotional stimuli in psychopathic individuals, and suggest differing roles for the 2 facets of psychopathy in affective processing deviations.     

Frames and brains: elicitation and control of response tendencies

Using magnetic resonance imaging, De Martino and colleagues investigated the neural signature that is associated with decisions between small sure amounts of money and large riskier amounts when the framing of the outcomes is varied. We interpret their results within a dual-system framework, in which different frames evoke distinct emotional responses that different individuals can suppress to various degrees. The study advances the integration of brain imaging results into cognitive theory.     

Imitative response tendencies following observation of intransitive actions

Clear and unequivocal evidence shows that observation of object affordances or transitive actions facilitates the activation of a compatible response. By contrast, the evidence showing response facilitation following observation of intransitive actions is less conclusive because automatic imitation and spatial compatibility have been confounded. Three experiments tested whether observation of a finger movement (i.e., an intransitive action) in a choice reaction-time task facilitates the corresponding finger movement response because of imitation, a common spatial code, or some combination of both factors. The priming effects of a spatial and an imitative stimulus were tested in combination (Experiment 1), in opposition (Experiment 2), and independently (Experiment 3). Contrary to previous findings, the evidence revealed significant contributions from both automatic imitation and spatial compatibility, but the priming effects from an automatic tendency to imitate declined significantly across a block of trials whereas the effects of spatial compatibility remained constant or increased slightly. These differential effects suggest that priming associated with automatic imitation is mediated by a different regime than priming associated with spatial compatibility.     

Response probability and similarity of retrieved response tendencies as determinants of response suppression difficulty

The primary objective of this study was to test the validity of the here labelled ‘suppression-time’ assumption which contends that the more difficult the response suppression operation, the longer the time required for its successful implementation. A secondary interest addressed the possibility that output suppression difficulty would be influenced by the level of response-response (R-R) compatibility existing between retrieved response tendencies. Two basic requirements confronted subjects within an experimental session: (a) dual-initiation (Dual-I) of paired arm movements, (b) initiation/suppression (I/S) of retrieved outputs, the irrelevant response being suppressed, the relevant output initiated. RT(I/S) magnitude and failure-to-inhibit error frequency increased as response probability increased, thereby providing support for the ‘suppression-time’ assumption. But R-R compatibility degree variations, when realized, did not consistently affect response suppression difficulty.     

Touch attenuates infants’ physiological reactivity to stress

Animal studies demonstrate that maternal touch and contact regulate infant stress, and handling during periods of maternal deprivation attenuates the stress response. To measure the effects of touch on infant stress reactivity during simulated maternal deprivation, 53 dyads were tested in two paradigms: still‐face (SF) and still‐face with maternal touch (SF+T). Maternal and infant cortisol levels were sampled at baseline, reactivity, and recovery and mother’s and infant’s cardiac vagal tone were measured during the free play, still‐face, and reunion episodes of the procedure. Cortisol reactivity was higher among infants in the SF condition and while cortisol decreased at recovery for infants in the SF+T, it further increased for those in the SF. Vagal tone showed a greater suppression when SF was not accompanied by maternal touch. Touch synchrony during free play was associated with higher infant vagal tone, whereas touch myssynchrony – maternal tactile stimulation while the infant gaze averts – correlated with higher maternal and infant cortisol. In humans, as in mammals, the provision of touch during moments of maternal unavailability reduces infants’ physiological reactivity to stress.     

Stuck in a rut: perseverative response tendencies and the neuroticism-distress relationship

Clinical views of neuroticism-linked distress often make reference to the perseverative sorts of mental processes that reinforce such experiences. The goal of the present 7 studies, involving 488 undergraduate participants, was to directly examine such perseverative processes. Individual differences in response perseveration were operationalized in terms of choice reaction time difficulties switching (vs. repeating) responses across consecutive trials. Response perseveration interacted with neuroticism in predicting negative emotion, dissatisfaction with life, and displays of negative emotion (Studies 1-4). Specifically, neuroticism-outcome relations were quite a bit stronger at high levels of perseveration. Additional studies (Studies 5-7) provided support for the convergent and discriminant validity of response perseveration. Overall, the results highlight the manner in which response perseveration reinforces experiences of negative emotion.     

Reaction time indices of automatic imitation measure imitative response tendencies

In his review, Ramsey (2018) argues that it is currently unclear what reaction time indices of automatic imitation measure due to lacking research on their validity and domain-specificity. In our commentary, we argue that this conclusion is based on two misconceptions, namely that automatic imitation was designed as a laboratory measure of motor mimicry and that psychometric approaches to validity can readily be applied to experimental settings. We then show that reaction time indices of automatic imitation measure covert imitative response tendencies. Furthermore, while irrelevant for their validity, we argue that these indices are associated with some, but not necessarily all, types of overt imitation. Finally, we argue that mapping out the brain networks does not suffice to understand the brain processes underlying imitative control.