Social transmission of natural variations in pain behaviour

Is Pain Contagious? Innocuous Stimulation Can be Transformed Into the Pain Experience by Observational Learning

Studies indicate that classical and operant conditioning have potential to play a role in the formation of the allodynic effect. Only a few studies have examined the role of observational learning in pain induction. Due to some methodological challenges, evidence that the allodynic effect can be learned through observation is limited. In the present study, healthy participants (n = 88) received 2 series of innocuous electrocutaneous stimuli: at the beginning of the study and after observation of a model who rated all the stimuli as painful. Participants and the model rated all the stimuli alternately (real-time group), or the participant first observed the model and then rated the stimuli, while the model stayed in (post-hoc+ group) or left (post-hoc- group) the laboratory. There was no model in the control group. The study demonstrated that allodynia can be induced by observational learning. Furthermore, this effect was shown to be similar, regardless of whether stimuli were received during the observation of the model and rated immediately afterwards, or when the observation and stimuli reception were time-separated. The mere presence of the model during the stimuli reception also did not affect the magnitude of this effect. This research may contribute to our understanding of the mechanisms of chronic pain development and assist in the development of suitable treatment for it. PERSPECTIVE: This article presents study results on the role of observational learning in allodynia induction without tissue injury. The results may contribute to our understanding of the mechanisms of chronic pain development and assist in the development of suitable treatment for it.

The effectiveness of parental distraction during children's acute pain: The moderating effect of socioeconomic status

BACKGROUND

Parental responses to children's pain shape how children interpret and cope with pain symptoms through parental modelling and operant conditioning. Evidence suggests that parental distraction is effective in reducing children's acute pain responses, but findings are inconsistent across pain tolerance, intensity and unpleasantness, and are limited to samples of primarily middle and upper-middle class families. Although socioeconomically disadvantaged families may have fewer psychological resources to cope with pain, no studies have examined whether the utility of parent distraction varies by family socioeconomic status (SES). The current study tested the hypothesis that relations between parental distraction and acute pain responses in children vary by family SES, with children from higher versus lower SES families experiencing more substantial benefits.

METHODS

Children's pain symptoms and parents' use of verbal distraction during a cold pressor task were examined in a community sample of 530 twin children aged 7-12 years old and their primary caregivers.

RESULTS

Parental distraction was positively associated with children's pain tolerance and unrelated to intensity and unpleasantness, but these associations are qualified by significant moderation. In families with higher SES, parental distraction was an effective technique in children's pain management, associated with more pain tolerance and less pain intensity and unpleasantness. However, for families with lower SES, these same benefits were not present.

CONCLUSIONS

Findings suggest that the effectiveness of parental distraction for children's acute pain may depend on family SES.

SIGNIFICANCE

Study findings suggest that the effects of parental distraction on children's responses to an acute pain task vary by family SES. Although parental distraction may be effective for higher SES children, further research is needed to identify whether and why distraction may not be beneficial for lower SES families.

A child in pain: A psychologist’s perspective on changing priorities in scientific understanding and clinical care

My research and clinical career followed a trajectory of increasing appreciation for the importance of social factors as determinants of pain experience and expression. The social contexts of children’s lives determine whether infants and children are exposed to pain, how socialization in family and ethnocultural contexts lead to pain as a social experience, comprised of thoughts and feelings as well as sensory input, how others shape pain experience and expression, less so for automatic/reflexive features than purposeful representations, and how other's appraisals of children’s pain reflect the observer's unique background and capacities for intervening in the child’s interests. A greater understanding of the social dimensions of pain, as reflected in the social communication model of pain, would support innovation of psychological and social interventions.

Rewarded placebo analgesia: A new mechanism of placebo effects based on operant conditioning

BACKGROUND

Placebo analgesia is explained by two learning processes: classical conditioning and observational learning. A third learning process, operant conditioning, has not previously been investigated as a mechanism of placebo effects. We aimed to induce placebo analgesia by operant conditioning.

METHODS

Three groups of participants received electrocutaneous pain stimuli of the same intensity, preceded by either an orange or blue stimulus. In the conditioning phase of the study, participants from the experimental group were rewarded for low pain responses following one of the colour stimuli (placebo) and for high pain responses following the other colour stimuli (non-placebo). Moreover, they were punished when their pain responses were high following placebo stimuli and low following non-placebo stimuli. To investigate the role of contingency, that is dependent relation between rewards/punishers and pain responses, the random-control group received rewards and punishers in a non-contingent manner. The colour-control group did not receive any rewards or punishers to control for nonassociative learning. Pain intensity ratings were used as an outcome measure, and verbal feedback on pain ratings was used as rewards/punishers.

RESULTS

When rewarding and punishment were stopped, only participants from the experimental group experienced less pain following the placebo than following the non-placebo stimuli; that is, placebo analgesia was found in this group. This effect was not extinguished during the study.

CONCLUSIONS

Placebo analgesia can be induced by operant conditioning, which should be considered a third mechanism for producing placebo effects. Moreover, the contingency between pain responses and rewards/punishers is crucial to induce placebo analgesia through operant conditioning.

SIGNIFICANCE

According to the current placebo literature, placebo analgesia can be explained by two learning processes: classical conditioning and observational learning. A third learning process, operant conditioning, has not previously been investigated as a mechanism of placebo effects. Our study reveals that patients can learn placebo analgesia as a result of operant conditioning, suggesting that randomized controlled trials could be improved by controlling the reinforcement that might occur spontaneously when patients interact with, for example, medical personnel.

Mothers' modeling influences children's pain during a cold pressor task

We set out to determine whether observing one's mother's reaction during a cold pressor test changes ratings of pain threshold, pain intensity, and observed pain-related facial behavior during a cold pressor test, using a Repeated Measures Mixed Factorial design in the setting of the Psychology Department, Dalhousie University, Halifax, Canada. The participants were: 96 mothers (mean age 41 years,) and 96 children (48 males, mean age 12.6 years), all in good general health. Pain intensity was measured using a 0-10 rating scale. Pain threshold was measured by asking participants to signal the moment any pain began and recording time elapsed since immersion. The Child Facial Coding System (CFCS; Revised manual for the child facial coding system (unpublished). Dalhousie University and University of British Columbia; Chambers et al., 1996) measured pain-related facial behavior. Mothers assigned to the Exaggerate condition were instructed, via videotape, to slightly exaggerate their display of pain and indicate a pain threshold within the first 10-20 s of a 4-min cold pressor task using water at 10 degrees C. Mothers in the Minimize condition were instructed to minimize their display of pain. Mothers assigned to the Control condition were given no specific instructions. All mothers privately rated their own pain intensity every 30 s. Children then completed a similar cold pressor task and made similar ratings. Children assigned to the Exaggerate Group (mean 21.7 s; SD 3.9) had lower thresholds than did children in the Control Group (mean 35.6 s; SD 21.8; t(1,76)=2.515, P=0.014). No difference in threshold was observed between the Control and the Minimize Groups (mean 32.2 s; SD 4.2; t(1,76)=0.610, P=0.544). No differences were observed in the self-report pain ratings of children between groups (F<1). CFCS Scores were significantly lower in the Minimize group compared to the Control group (95% CI 4.98-20.19, P=0.001), but no difference was noted between the Exaggerate and Control groups (95% CI -8.03-6.93, P=0.884). Children's pain threshold and their facial behavior are altered by exposure to mother's behavior during a cold pressor task suggesting that modeling has an impact on a child's pain behavior.

Differences in postoperative pain severity among four ethnic groups

Subjects (N = 543) reporting on acute postoperative dental pain were classified into four major ancestral groups: Asian (N = 96), black American (N = 65), European (N = 296), and Latino (N = 88). Pain severity was measured using a 10-cm visual analogue scale following a standardized operative procedure. The subjects of European descent reported significantly less severe pain than those of black American or Latino descent. They also reported less pain than Asians, although this finding did not reach significance. Evaluation of covariates, including gender, age, education, generation in the United States, and difficulty of the surgical extraction, demonstrated that gender was significant, with men reporting less pain than women regardless of ancestry. Possible implications of these findings are discussed in terms of potential differences in physiology, in addition to social learning.