Aversive event unpredictability causes stress-induced hypoalgesia

Amadeu Quelhas Martins, David McIntyre, Christopher Ring

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


Temporal predictability, or knowing when a noxious stimulus will occur, has been implicated in stress‐induced hypoalgesia, but the contribution of event predictability, or knowing what the stimulus will be, remains poorly understood. To address this issue, we examined the effects of event predictability on pain intensity ratings and nociceptive flexion reflex responses. Participants repeatedly experienced five intensities of electrocutaneous stimulation, ranging from nonpainful to extremely painful, delivered either randomly (unpredictability group) or blocked (predictability group) with no cues provided. Unpredictable shocks produced the lowest pain ratings while evoking the highest flexion reflex responses. Moreover, anticipatory heart rate data indicated that unpredictable trials were the most physiologically arousing. Our findings show that uncertainty about the upcoming stimulus intensity is stressful and unpleasant, thereby causing hypoalgesia and reflex potentiation.
Original languageEnglish
Pages (from-to)1066-1070
Number of pages5
Issue number8
Early online date29 Mar 2015
Publication statusPublished - Aug 2015


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