Cognition 103 (2007) 491–501 www.elsevier.com/locate/COGNIT 0010-0277/$ - see front matter  2006 Elsevier B.V. All rights reserved. doi:10.1016/j.cognition.2006.04.011 Brief article Can blindsight be superior to ‘sighted-sight’?  Ceri T. Trevethan ¤ , Arash Sahraie, Larry Weiskrantz Vision Research Laboratories, School of Psychology, University of Aberdeen, Aberdeen, AB24 2UB Scotland, UK Received 11 January 2006; revised 20 April 2006; accepted 21 April 2006 Abstract DB, the Wrst blindsight case to be tested extensively (Weiskrantz, 1986) has demonstrated the ability to detect and discriminate a range of visual stimuli presented within his perimetri- cally blind visual Weld defect. In a temporal two alternative forced choice (2AFC) detection experiment we have investigated the limits of DB’s detection ability within his Weld defect. Blind Weld performance was compared to his sighted Weld performance and to an age-matched control group (n D 6). DB reliably detected the presence of a small (2°), low contrast (7%), 4.6 c/° Gabor patch with the same space-averaged luminance as the background presented within his blind Weld but performed at chance levels at the same eccentricity (11.3°) within his sighted Weld. Investigation of detection as a function of stimulus contrast revealed DB’s ability to detect the presence of an 8% contrast stimulus within his blind Weld, compared to 12% in his sighted Weld. No signiWcant diVerence in detection performance between DB’s sighted Weld and the performance of six age-matched control participants suggests poor sighted Weld perfor- mance does not account for the results. Monocular testing also rules out diVerences between the eyes as an explanation, suggesting that DB demonstrates superior detection for certain stimuli within his visual Weld defect compared to normal vision.  2006 Elsevier B.V. All rights reserved. Keywords: Blindsight; Contrast sensitivity; Two alternative forced choice detection  This manuscript was accepted under the editorship of Jacques Mehler. * Corresponding author. Tel.: +44 0 1224 274393; fax: +44 0 1224 273426. E-mail address: c.trevethan@abdn.ac.uk (C.T. Trevethan).