The phenomenology of controlling a moving object with another person John A. Dewey a,⇑ , Elisabeth Pacherie b , Guenther Knoblich a a Department of Cognitive Science, Central European University, Frankel Leó út 30-34, Budapest 1023, Hungary b Institut Jean Nicod, UMR 8129, Pavillon Jardin, Ecole Normale Supérieure, 29 rue d’Ulm, F-75005 Paris, France article info Article history: Received 8 October 2013 Revised 19 March 2014 Accepted 6 May 2014 Keywords: Agency Control Joint action Phenomenology abstract The phenomenology of controlling what one perceives is inﬂuenced by a combination of sensory predictions and inferential processes. While it is known that external perturba- tions can reduce the sense of control over action effects, there have been few studies inves- tigating the impact of intentional co-actors on the sense of control. In three experiments, we investigated how individuals’ judgments of control (JoC) over a moving object were inﬂuenced by sharing control with a second person. Participants used joysticks to keep a cursor centered on a moving target either alone or with a co-actor. When both participants’ actions had similar perceptual consequences, JoC ratings were highest when self-generated movements were the only inﬂuence on the cursor, while the appearance of sharing control with a second person decreased JoC ratings. By contrast, when participants performed complementary actions with perceptually distinctive consequences, JoC ratings were high- est when both participants were able to inﬂuence the cursor. The phenomenology of con- trol during joint action is inﬂuenced by low-level visuomotor correlations, the presence of competing causal inﬂuences, and group-level performance. Ó 2014 Elsevier B.V. All rights reserved. 1. Introduction To control something is to act in order to bring it to a pre-speciﬁed condition, possibly in the face of external forces or changes in the environment that tend to alter it (Powers, 1978). This broad deﬁnition encompasses most purposeful human behavior, as voluntary actions are usually performed with the intent of producing a particular change in the environment that can be perceived as a sensory outcome of performance (henceforth ‘‘action effects’’). The question of what processes contribute to the phe- nomenology of controlling what one perceives has moti- vated much research. The emerging consensus is that the sense of control is not a unitary phenomenon, but rather depends on a combination of efferent motor signals, sensory predictions and higher level cognitive processes (Haggard & Tsakiris, 2009; Pacherie, 2008; Synofzik, Vosgerau, & Newen, 2008). The sense of control over body movements is thought to depend on a system of sensori- motor comparators which detects discrepancies between sensory predictions triggered by efferent motor signals, and actually executed movements (Blakemore, Wolpert, & Frith, 1998; Frith, 2012; Tsakiris, Haggard, Franck, Mainy, & Sirigu, 2005). Sensory predictions also inﬂuence the sense of control over distal events outside the body. For example, auditory stimuli triggered by keystrokes are more likely to be attributed to external sources when the timing or frequency is different from what was expected (Knoblich & Repp, 2009; Sato & Yasuda, 2005). The sense of control can also be inﬂuenced by inferen- tial processes. For example, priming unintended action effects has been shown to increase feelings of authorship, http://dx.doi.org/10.1016/j.cognition.2014.05.002 0010-0277/Ó 2014 Elsevier B.V. All rights reserved. ⇑ Corresponding author. Tel.: +36 1 887 5136. E-mail address: DeweyJ@ceu.hu (J.A. Dewey). Cognition 132 (2014) 383–397 Contents lists available at ScienceDirect Cognition journal homepage: www.elsevier.com/locate/COGNIT