Unconscious Processing of Body Actions Primes Subsequent Action Perception but Not Motor Execution Sonia Mele, Alan D. A. Mattiassi, and Cosimo Urgesi University of Udine and Scientific Institute IRCCS Eugenio Medea, San Vito al Tagliamento, Pordenone, Italy Previous studies have shown that viewing body actions primes not only the visual perception of congruent versus incongruent actions, but also their motor execution. Here, we used a masked-priming paradigm to explore whether visuoperceptual and visuomotor action priming may also occur when the prime is not consciously perceived. In 5 experiments, healthy individuals were presented with masked implied-action primes and were then prompted to perceive congruent or incongruent implied-action stimuli or to execute congruent or incongruent finger movements. Results showed that implied-action primes affected subsequent action perception also when they were not consciously perceived. Uncon- scious visuoperceptual action priming effects were independent from spatial compatibility and reflected genuine action representation. Conversely, masked implied-action primes affected motor preparation and execution processes only when they were consciously perceived. The results provide evidence of unconscious visuoperceptual but not visuomotor action priming effects, suggesting that unconscious processing of actions affects perceptual, but not motor representations. Keywords: automatic imitation, masked priming, motor resonance, stimulus response compatibility, unconscious processing Common coding hypotheses claim that perceived and executed actions are represented in a common code (Hommel, Müsseler, Aschersleben, & Prinz, 2001; Prinz, 1997; Schütz-Bosbach & Prinz, 2007), suggesting a bidirectional, causal link between per- ceptual and motor processing (Avenanti, Candidi, & Urgesi, 2013; Avenanti & Urgesi, 2011). In keeping with these hypotheses, several studies have shown that action execution induces short- term (Casile & Giese, 2006; Cattaneo & Barchiesi, 2011; Hamil- ton, Wolpert, Frith, & Grafton, 2006) and long-lasting (Abernethy, Zawi, & Jackson, 2008; Aglioti, Cesari, Romani, & Urgesi, 2008; Urgesi, Savonitto, Fabbro, & Aglioti, 2012) effects on the way others’ actions are perceived. On the other hand, there is also evidence that action perception influences the execution of one’s own motor actions. Indeed, observing a moving body parts facil- itates not only the subsequent perception of similar actions (visuo- perceptual priming; Costantini, Committeri & Galati, 2008; Gül- denpenning, Koester, Kunde, Matthias, & Schack, 2011), but also the execution of congruent as compared with incongruent body movements (visuomotor priming or automatic imitation; Brass, Bekkering, Wohlschläger, & Prinz, 2000; Heyes, 2011; Kilner, Paulignan, & Blakemore, 2003; Stürmer, Aschersleben, & Prinz, 2000). The visuomotor action priming effect is found when view- ing either dynamic action sequences (Brass et al., 2000; Brass, Bekkering, & Prinz, 2001; Kilner et al., 2003; Stürmer et al., 2000) or single frames that imply actions (Brass et al., 2000; Craighero, Bello, Fadiga, & Rizzolatti, 2002; Craighero, Fadiga, Rizzolatti, & Umilta `, 1999; Craighero, Fadiga, Umilta `, & Rizzolatti, 1996; Vogt, Taylor, & Hopkins, 2003). Furthermore, the effect is con- sidered automatic because it is independent from the observer’s intent to imitate or even to process the action stimulus (Heyes, 2011) and it is not modulated by the predictability of the prime-cue association (e.g., manipulating the proportion of congruent and incongruent trials; Hogeveen & Obhi, 2013). It is unknown, how- ever, whether action priming effects require perceptual awareness or whether they occur also in response to actions that are not consciously perceived. The present study was aimed at testing the effects of actions that are not consciously perceived on subsequent action perception and execution processes. A typical paradigm to test automatic imitation requires partici- pants to provide finger responses that are congruent or not with the observed finger movements (e.g., Brass et al., 2000). The re- sponses to congruent movements are faster than those to incon- gruent movements, suggesting the observer is automatically en- gaged in the simulation of the observed movement, although processing the action stimulus is not explicitly required by the task and is even detrimental for task performance (Brass et al., 2000). Further studies (Bertenthal, Longo, & Kosobud, 2006; Brass et al., 2001; Catmur & Heyes, 2011; Jiménez et al., 2012; Wiggett, Sonia Mele, Alan D. A. Mattiassi, and Cosimo Urgesi, Department of Human Sciences, University of Udine, Udine, Italy and Scientific Institute IRCCS Eugenio Medea, San Vito al Tagliamento, Pordenone, Italy. The first and last authors thank Prof. G. Berlucchi for his generous support during their initial research training and for insightful discussion on topics related to the present study. The research was supported by grants from Istituto Italiano di Tecnologia SEED 2009 [Prot. no. 21538; to Cosimo Urgesi], from the Ministero Istruzione Universita ` e Ricerca [Progetti di Ricerca di Interesse Nazionale, PRIN 2009; Prot. no. 2009A8FR3Z; Futuro In Ricerca, FIR 2012, Prot. N. RBFR12F0BD; to Cosimo Urgesi], and from Istituto di Ricovero e Cura a Carattere Scientifico “E. Medea” [Ricerca Corrente 2012, Ministero Italiano della Salute; to Cosimo Urgesi,]. The authors declare no competing financial interests. Correspondence concerning this article should be addressed to Sonia Mele, Department of Human Sciences, University of Udine, via Margreth, 3, I-33100, Udine, Italy. E-mail: sonia.mele@uniud.it This document is copyrighted by the American Psychological Association or one of its allied publishers. This article is intended solely for the personal use of the individual user and is not to be disseminated broadly. Journal of Experimental Psychology: Human Perception and Performance © 2014 American Psychological Association 2014, Vol. 40, No. 2, 000 0096-1523/14/$12.00 DOI: 10.1037/a0036215 1 AQ: 1 AQ: au AQ: 2 AQ: 7 tapraid5/zfn-xhp/zfn-xhp/zfn00214/zfn3067d14z xppws S=1 3/7/14 18:10 Art: 2013-1385 APA NLM