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.     

Sensory and affective judgments of skin during inter- and intrapersonal touch

Here we report two experiments that investigated the tactile perception of one’s own skin (intrapersonal touch) versus the skin of other individuals (interpersonal touch). In the first experiment, thirteen female participants rated, along four perceptual attributes, the skin of their own palm and volar forearm, then that of several of the other participants. Ratings were made using visual analogue scales for perceived smoothness, softness, stickiness, and pleasantness. One’s own skin was rated less pleasant than the skin of others. For both intra- and interpersonal touch, the forearm skin was rated smoother, softer, less sticky and more pleasant than the palmar skin. In the second experiment, ten pairs of female participants rated each other’s palm and volar forearm skin, with the skin of the touched individual being assessed before and after the application of skin emollients that alter skin feel. As in the first experiment, the untreated skin of others was rated more pleasant than the participants’ own skin, and the forearm versus palm differences were replicated. However, the emollient had generally larger effects on self-assessments than the assessments of others, and the site effect showed greater positive sensory and pleasantness increases for palm versus volar forearm. The disparate results of the two experiments suggest that attention, influenced by the ecological importance of the stimulus, is more important to assessment of touched skin than ownership of the skin or the contribution to self-touch made by the additional receptors in the passively touched skin. In both experiments, the pleasantness of touched skin was associated with the skin’s perceived smoothness and softness, with weak trends toward negative associations with its perceived stickiness, consistent with prior research using inanimate surfaces (e.g., textiles and sandpapers).     

Facial-expression affective attributes and their configural correlates: components and categories

The present study investigates the perception of facial expressions of emotion, and explores the relation between the configural properties of expressions and their subjective attribution. Stimuli were a male and a female series of morphed facial expressions, interpolated between prototypes of seven emotions (happiness, sadness, fear, anger, surprise and disgust, and neutral) from Ekman and Friesen (1976). Topographical properties of the stimuli were quantified using the Facial Expression Measurement (FACEM) scheme. Perceived dissimilarities between the emotional expressions were elicited using a sorting procedure and processed with multidimensional scaling. Four dimensions were retained in the reconstructed facial-expression space, with positive and negative expressions opposed along D1, while the other three dimensions were interpreted as affective attributes distinguishing clusters of expressions categorized as "Surprise-Fear," "Anger," and "Disgust." Significant relationships were found between these affective attributes and objective facial measures of the stimuli. The findings support a componential explanatory scheme for expression processing, wherein each component of a facial stimulus conveys an affective value separable from its context, rather than a categorical-gestalt scheme. The findings further suggest that configural information is closely involved in the decoding of affective attributes of facial expressions. Configural measures are also suggested as a common ground for dimensional as well as categorical perception of emotional faces.     

Accessibility of affective versus cognitive components of attitudes

Four studies investigated differences in accessibility of affective and cognitive components of attitudes. Accessibility was measured by response times on bipolar semantic differential evaluative adjectives (e.g. ‘positive–negative’) in response to how one felt and thought, respectively, about an attitude object. The evaluative items were accompanied by affective and cognitive context items, which were not analysed, but were meant to promote the retrieval of affective and cognitive evaluations respectively. Responses to affective evaluations were given faster than responses to cognitive evaluations, suggesting that affect-based evaluations are more accessible in memory than cognition-based evaluations. The results were obtained in two attitude domains, i.e. brand names and countries. The results support the validity of a two-component affect–cognition model of attitude. © 1998 John Wiley & Sons, Ltd.     

Neural basis of affective touch and pain: A novel model suggests possible targets for pain amelioration

Pain is one of the most common health problems and has a severe impact on quality of life. Yet, a suitable and efficient treatment is still not available for all patient populations suffering from pain. Interestingly, recent research shows that low threshold mechanosensory C-tactile (CT) fibres have a modulatory influence on pain. CT-fibres are activated by slow gentle stroking of the hairy skin, providing a pleasant sensation. Consequently, slow gentle stroking is known as affective touch. Currently, a clear overview of the way affective touch modulates pain, at a neural level, is missing. This review aims to present such an overview. To explain the interaction between affective touch and pain, first the neural basis of the affective touch system and the neural processing of pain will be described. To clarify these systems, a schematic illustration will be provided in every section. Hereafter, a novel model of interactions between affective touch and pain systems will be introduced. Finally, since affective touch might be suitable as a new treatment for chronic pain, possible clinical implications will be discussed.     

A different kind of pain: affective valence of errors and incongruence*

People hiss and swear when they make errors, frown and swear again when they encounter conflicting information. Such error- and conflict-related signs of negative affect are found even when there is no time pressure or external reward and the task itself is very simple. Previous studies, however, provide inconsistent evidence regarding the affective consequences of resolved conflicts, that is, conflicts that resulted in correct responses. We tested whether response accuracy in the Eriksen flanker task will moderate the effect of trial incongruence using affective priming to measure positive and negative affect. We found that responses to incongruent trials elicit positive affect irrespective of their accuracy. Errors, in turn, result in negative affect irrespective of trial congruence. The effects of conflicts and errors do not interact and affect different dimensions of affective priming. Conflicts change the speed of evaluative categorisation while errors are reflected in categorisation accuracy. We discuss the findings in light of the “reward value and prediction” model and the “affect as a feedback for predictions” framework and consider the possible mechanisms behind the divergent effects.     

Cognitive and affective components of life events: Their relations and effects on weil-being

A model of how five key facets of life events are related to one another and influence mental health and functioning was examined. The facets are the experience of control over, anticipation of, pleasantness from, stress generated by, and adjustment to life events. Multivariate analyses of data from 420 adult male respondents yielded results that were largely consistent with the hypothesized model. The results suggested that control over and anticipation of life events influenced the perceived stress produced by the events and the ability to adjust to them. In turn, it appeared that such stress and adjustment influenced mental health and functioning. The effects of control and anticipation on mental health and functioning were indirect only. Contrary to our hypothesis, control seemed to heighten perceived stress; but control, as well as anticipation, appeared to increase the ability to adjust. Whereas previous studies found no effect of desirable events on well-being, this study found that pleasant events had a beneficial effect. The discussion examines the implications of the findings for future research.     

The puzzle of joking: Disentangling the cognitive and affective components of humorous distraction

Studies in cognitive psychology, marketing, and education indicate that humor distracts attention from non‐humorous information presented at the same time. Two experiments investigated why humor distracts attention. The two basic components of humor comprise (1) incongruency resolution, which poses cognitive demands and (2) positive affect. We disentangled the contributions of cognitive demands and positive affect on distraction based on the notions that (a) both components are possible sources of distraction, and (b) the components were always confounded in previous research. In an evaluative conditioning paradigm, novel products were consistently paired with humorous stimuli, whereas other products were paired with stimuli that were either (1) equally demanding but neutral, (2) equally positive but undemanding, and (3) undemanding and neutral. The results showed that cognitively demanding stimuli distracted attention, irrespective of stimulus positivity. These findings suggest that the cognitive demands of humor, not the positive affect it evokes, underlie the distraction effect. Copyright © 2009 John Wiley & Sons, Ltd.     

Alone but feeling no pain: Effects of social exclusion on physical pain tolerance and pain threshold, affective forecasting, and interpersonal empathy

Prior findings of emotional numbness (rather than distress) among socially excluded persons led the authors to investigate whether exclusion causes a far-reaching insensitivity to both physical and emotional pain. Experiments 1-4 showed that receiving an ostensibly diagnostic forecast of a lonesome future life reduced sensitivity to physical pain, as indicated by both (higher) thresholds and tolerance. Exclusion also caused emotional insensitivity, as indicated by reductions in affective forecasting of joy or woe over a future football outcome (Experiment 3), as well as lesser empathizing with another person's suffering from either romantic breakup (Experiment 4) or a broken leg (Experiment 5). The insensitivities to pain and emotion were highly intercorrelated.     

Chronic pain, stress, and the dynamics of affective differentiation

We describe a program of research examining how the relationship between positive and negative affect varies both between individuals and within individuals over time. This Dynamic Model of Affect (DMA) proposes that under conditions that promote maximal information processing, positive and negative affective systems function relatively independently. In contrast, under conditions characterized by uncertainty, including pain and stress, the affects become strongly inversely related. Included in our consideration are potential individual differences in the ability to sustain affective differentiation during pain and other stressors and the implications of this model for perceptions of social relations and for interventions to improve well-being among the chronically ill.     

Chronic pain relief after receiving affective touch: A single case report

Affective touch is gentle slow stroking of the skin, which can reduce experimentally induced pain. Our participant, suffering from Parkinson's Disease and chronic pain, received 1 week of non-affective touch and 1 week of affective touch as part of a larger study. Interestingly, after 2 days of receiving affective touch, the participant started to feel less pain. After 7 days, the burning painful sensations fully disappeared. This suggest that affective touch may reduce chronic pain in clinical populations.     

Independent effects of emotion and attention on sensory and affective pain perception

The present study investigated whether attention and emotion independently influence sensory and affective pain ratings. Fifty-four (27 female) participants rated sensory and affective pain in response to painful mechanic pressure stimulation while exposed to positive, neutral and negative slides from the International Affective Picture System. In doing so, participants were assigned to one of three groups, which focused attention either on the pictures or on the sensory or on the affective aspects of the pressure stimulation. Consistent with the motivational priming hypothesis, sensory and affective pain ratings were generally lower during exposure to positive compared to negative and neutral slides. In line with our assumptions, attention modulated sensory pain ratings with lowest ratings in the picture focusing group and highest in the affective pain focusing group. No attention effect for affective pain ratings and no interactions between emotional and attentional effects on pain perception were found.     

Some affective consequences of social comparison and reflection processes: the pain and pleasure of being close

A self-evaluation maintenance (SEM) model of social behavior was described. According to the comparison process, when another outperforms the self on a task high in relevance to the self, the closer the other the greater the threat to self-evaluation. According to the reflection process, when another outperforms the self on a task low in relevance to the self, the closer the other the greater the promise of augmentation to self-evaluation. Affect was assumed to reflect threats and promises to self-evaluation. In three studies, subjects were given feedback about own performance and the performance of a close (friend) and distant (stranger) other on tasks that were either low in self-relevance (Study 2) or that varied in self-relevance (Studies 1 and 3). In Study 1 (N = 31), subjects' performance on simple and complex tasks after each feedback trial served as a measure of arousal. Being outperformed by a close other resulted in greater arousal than being outperformed by a distant other. In Study 2 (N = 30), evaluative ratings of words unrelated to task performance served as an indirect measure of affect. Results indicated that when relevance is low, more positive affect is associated with a friend's outperforming the self than either a friend's performing at a level equal to the self or being outperformed by a stranger. In Study 3 (N = 31), subjects received feedback while their facial expressions were monitored. Pleasantness of expression was an interactive function of relevance of task, relative performance, and closeness of comparison other. The results of all three studies were interpreted as being generally consistent with the SEM model.     

Sensory information,fear level,and reactions to pain1

An experiment was conducted to investigate the conditions under which sensory information has beneficial versus detrimental value as preparatory information to assist individuals in coping with stress. Fourteen high fear and twelve low fear college women underwent exposure to the cold pressor test. Half of each fear group was provided with sensory information about the sensations produced by the cold pressor and half received a control message. Distress judgments made during the cold pressor showed (a) that sensory information effectively reduced distress for low fear women, but (b) sensory information exacerbated the distress of high fear women—at least during early portions of the cold pressor test. The data generally support Leventhal's (1979) perceptual-motor theory of emotion and have pragmatic implications for those persons who provide preparatory information to individuals anticipating a stressful encounter.     

Capturing frequency components of glided tones: Frequency separation,orientation, and alignment

If two sinusoidal glides, Y and Z, synchronous in onset and offset, glide in parallel on a log frequency scale, they fuse and sound like a single rich glide. However, it is possible to capture Y (the target) into a sequential stream by using as a captor a pure tone glide, X, that precedes the YZ glide in a repeating cycle. The cycle then breaks perceptually into two streams, an XY stream and a Z stream. The strength of capturing depends on the similarity of the captor and target glides with respect to both frequency range and orientation. There appears to be no special capturing effect when the captor and target glides are aligned on a common trajectory.     

Elevated emotional reactivity in affective but not cognitive components of theory of mind: A psychophysiological study

Recent research proposes that theory of mind (ToM), that is the ability to infer other people's mental state, is a multidimensional construct and that a distinction may be made between affective and cognitive ToM. We examined whether these two subcomponents of ToM correspond to different levels in skin conductance responses (SCRs). Seventeen healthy adults listened to ten affective (faux pas) ToM stories, ten cognitive ToM stories and ten non‐ToM stories. Results demonstrated significantly elevated SCR for affective ToM as compared with cognitive ToM and control stories, with no differences in SCR levels in the latter two story types. We discuss the possible underlying mechanisms for these differential psychophysiological correlates of affective and cognitive ToM processing, and suggest further investigations especially in clinical populations.