[1] Royal Holloway Univ London, Dept Psychol, Egham Hill, Egham TW20 0EX, Surrey, England
[2] Novartis Pharmaceut, Dublin, Ireland
[3] Birkbeck Univ London, Dept Psychol Sci, Malet St, London WC1E 7HX, England
[4] UCL, Dept Expt Psychol, London, England
[5] Queen Mary Univ London, Sch Elect Engn & Comp Sci, Mile End Rd, London E1 4NS, England
[6] Aarhus Univ, Dept Clin Med, Aarhus, Denmark