The effect of social influence on relief-learning

Introduction Anticipation of pain triggers defensive responses such as startle potentiation, while its avoidance and termination result in positive sensations such as startle attenuation, called relief. These responses can become associated with and later elicited by other stimuli concurrently present. Importantly, social support reduces aversiveness of pain.

Methods We investigated the effect of social influence on relief responses and whether active relief (avoidance) differs from passive relief (pain termination) in 102 healthy females. During acquisition, the active group (N = 33) learned to actively oppress a painful stimulation (unconditioned stimulus, US), the social group (N = 35) believed that another participant oppressed the US, and the passive group (N = 34) had no influence. A visual stimulus (conditioned stimulus, CS+) followed US' termination. Subsequently (test phase), participants heard aversive startle probes presented with the CS+ or a novel visual stimulus (Control). Startle responses and fear ratings were collected as learning indices.

Results After acquisition, all participants rated CS+ as more frightening than Control, suggesting that on the explicit level, the relief-associated stimulus elicited fear in all groups. After test, fear ratings of CS+ further increased but did not differ from Control. The same was evident for startle responses to CS+ and Control in both passive and active group. Thus, physiological responses indicate equal implicit valence for passive and active relief. In comparison, the social group showed overall lower startle responses. However, responses were higher to CS+ than Control.

Conclusion In sum, our results indicate that social influence reduces the physiological response to aversive events, but does not enhance relief learning.