Self-initiated action effects are often perceived as less intense than identical but externally generated stimuli. It is thought that forward models within the sensorimotor system pre-activate cortical representations of predicted action effects, reducing perceptual sensitivity and attenuating neural responses. As self-agency and predictability are seldom manipulated simultaneously in behavioral experiments, it is unclear if self-other differences depend on predictable action effect contingencies, or if both self- and externally generated stimuli are modulated similarly by predictability. We factorially combined variation in predictability (...) of action effects, spatial congruence, and performance by the self or computer to dissociate these influences on a visual discrimination task. Participants performed 2AFC speed judgments. Self-initiated motion was judged to be slower than computer-initiated motion when action effect contingencies were predictable, while spatial congruence influenced speed judgments only when action effect contingencies were unpredictable. Results are discussed in relation to current theories of sensory attenuation. (shrink)

The sense of agency is the perception of willfully causing something to happen. Wegner and Wheatley proposed three prerequisites for SA: temporal contiguity between an action and its effect, congruence between predicted and observed effects, and exclusivity . We investigated how temporal contiguity, congruence, and the order of two human agents’ actions influenced SA on a task where participants rated feelings of self-agency for producing a tone. SA decreased when tone onsets were delayed, supporting contiguity as important, but the order (...) of the agents’ actions also mattered. Relative contiguity was the main determinant of SA, as delayed tones were usually attributed to the most recent action. This was unaffected by contingencies between the two actors’ actions , showing that contiguity has a powerful influence on SA, even during joint action in the presence of other cues. (shrink)

The perception of sensory effects generated by one’s own actions is typically attenuated compared to the same effects generated externally. However, it is unclear whether this specifically relates to self-generation. Recent studies showed that sensory attenuation mainly relies on action preparation, not actual action execution. Hence, an attenuation of sensory effects generated by another person might occur if these actions can be anticipated and thus be prepared for.Here, we compared the perceived loudness of sounds generated by one’s own actions and (...) actions of another person that either could or could not be anticipated. We found an attenuation of the perceived loudness for self- as compared to other-generated sounds. This difference was independent of whether the sound-eliciting actions of the other person could be anticipated or not. Thus, sensory attenuation seems to be specifically tied to self-generation instead of being a secondary effect of agent-independent preparation for an upcoming action. (shrink)