Covariation bias in the affect-modulated startle paradigm.

A covariation bias (CB) reflects the overestimation of an objectively random covariation between fear-relevant picture stimuli (e.g., spiders) and aversive consequences (e.g., electric shocks). The affect-modulated startle (AMS) paradigm is similar to it because aversive reflex probes are delivered in the context of unpleasant, neutral or pleasant picture stimuli. The present study explored if a covariation bias is present in the affect-modulated startle paradigm. There was a covariation bias for unpleasant and pleasant compared to neutral pictures probably due to differences in arousal. Startle reflexes were modulated by picture valence. No correlation between a covariation bias index and the startle response modulation was found. It is concluded that both phenomena are mediated by different underlying mechanisms.