Generalization of instrumentally acquired pain-related avoidance to novel but similar movements using a robotic arm-reaching paradigm

• Published in: Behaviour research and therapy Vol. 124; p. 103525
• Main Authors: Glogan, Eveliina, Gatzounis, Rena, Meulders, Michel, Meulders, Ann
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.01.2020; Elsevier Science Ltd
• Subjects: Acquired; Arm; Avoidance behavior; Avoidance generalization; Chronic pain; Deviation; Disability; Expectancy; Fear; Fear & phobias; Fear generalization; Operant conditioning; Pain; Reinforcement; Resistance; Fear generalization; Operant conditioning; Avoidance generalization; Chronic pain; Avoidance behavior
• ISSN: 0005-7967; 1873-622X
• DOI: 10.1016/j.brat.2019.103525

Avoidance is considered a key contributor to the development and maintenance of chronic pain disability, likely through its excessive generalization. This study investigated whether acquired avoidance behavior generalizes to novel but similar movements. Using a robotic arm, participants moved their arm from a starting to a target location via one of three possible movement trajectories. For the Experimental Group, the shortest, easiest trajectory was always paired with pain (T1 = 100% reinforcement/no resistance and deviation). Pain could be partly or completely avoided by choosing increasingly effortful movements (T2 = 50% reinforcement, moderate resistance/deviation; T3 = 0% reinforcement, strongest resistance/largest deviation). A Yoked Group received the same number of painful stimuli irrespective of their own behavior. Outcomes were self-reported fear of movement-related pain, pain-expectancy, avoidance behavior, (maximal deviation from the shortest trajectory), and trajectory choice behavior. We tested generalization to three novel trajectories (G1-3) positioned next to the acquisition trajectories. Whereas acquired fear of movement-related pain and pain-expectancy generalized in the Experimental Group, avoidance behavior did not, suggesting that threat beliefs and high-cost avoidance may not be directly related. The lack of avoidance generalization may be due to a perceived context-switch in the configurations of the acquisition and the generalization phases. •Avoidance is a key characteristic of both anxiety and chronic pain disorders.•Chronic pain patients show altered fear learning, in particular overgeneralization.•Avoidance is the crucial link from fear to disability, yet an understudied topic.•We tested whether acquired operant avoidance behavior generalizes to new movements.•Pain-related fear and expectancy generalized to novel movements, avoidance did not.