University College London, London, UKControversy and disagreement lie at the heart of scientificadvance and hypnosis has had its fair share of detractors,given its chequered history in some areas of medicine andlong standing association with mysticism and stage hypno-tism (Raz and Shapiro, 2002). Nevertheless, despite someunderstandable scepticism, hypnosis’s compelling behav-ioural and experiential phenomena continued to providea small number of neuroscientists with a rich paradigm forunderstanding the nature of hypnosis and using it to manip-ulate aspects of phenomenological consciousness (Spiegelet al.,1982; Kihlstrom, 1987; Crawford and Gruzelier, 1992;Kirsch and Lynn, 1995; Oakley, 1999; Kosslyn et al., 2000; Razet al., 2002; Barnier and McConkey, 2003).Recently, however, hypnosis has begun to attract renewedinterest from cognitive and social neuroscientists interestedin using hypnosis and hypnotic suggestion to test predictionsabout normal cognitive functioning (Jamieson, 2007; Oakleyand Halligan, 2009; Terhune and Kadosh, 2012; Del Casaleetal.,2012;Priftisetal.,2011;Connors,2012;Hoeftetal.,2012).This renewed interest was partly facilitated by the growingacceptance of consciousness as a legitimate field of enquiryfor cognitive neuroscience (Marcel and Bisiach, 1988;Velmans, 1996) but also critically, by the findings fromneurophysiological tools (Hinterberger et al., 2011) and inparticular the widespread availability of functional-imagingtechniques (Raz and Shapiro, 2002; Oakley and Halligan,2009). In tandem with improvements in experimental designand subject screening, these studies are now making inroadsinto the functional anatomy of hypnosis (Jamieson, 2007)aswell as paving the way for its use as an experimental tool forneuroscience research (Oakley, 2006). In particular thesestudies have begun to address the sceptic’s concern regardingthe subjective reality and comparability of hypnoticallysuggested phenomena previously dependent on the subjects’largely unverifiable report and behaviour (Raz and Campbell,2011; Terhune and Kadosh, 2012).As one indication of the progress made, the cover of thisspecial issue brings together one of the very first and one ofthe most recent ways of demonstrating objectively the powerof suggestion. The foreground contains Chevreul’s pendulumwhile the background provides a representation of brainactivations seen following hypnotic suggestion during func-tional magnetic resonance imaging (fMRI). The pendulumeffect was described in 1833 by the French chemist Michel-Eugene Chevreul in an open letter to the physicist Andre´Ampe`re (Chevreul, 1833; Spitz, 1977). The effect involvesamplifying small, unconscious (ideomotor) movements of thehand, arm and body of the individual holding the pendulum.The origin and direction of the movement is determined bythecontentoftheconcurrentsuggestionsprovidedbyanotherperson, by environmental cues and/or by implicit expectan-cies (via autosuggestion) on the part of the person holding thependulum, who experiences the movement as occurring ‘allby itself’. This ideomotor response captured by the Chevreulpendulum effect is a classic hypnotic phenomenon respon-sible for the apparently spontaneous movements experiencedin the context of water divining, automatic writing, the use ofouija boards and table turning in se´ances. It is also a goodexample of ‘cold control’ e described by Dienes and Hutton(2013). The background image on the cover features approxi-mate surface projections of activated voxels revealed by fMRIduring hypnotically suggested heat pain (Derbyshire et al.,2004), superimposed on a glass brain. These activations weresimilar to those produced by an actual painful heat stimulusbut different from those seen when the hypnotised subjectwas instructed to imagine the same pain experience.