An increasing number of researchers are exploring variations of the Concealed Knowledge Test (CKT) as alternatives to traditional ‘lie-detector’ tests. For example, the response times (RT)-based CKT has been previously shown to accurately detect participants who possess privileged knowledge. Although several studies have reported successful RT-based tests, they have focused on verbal stimuli despite the prevalence of photographic evidence in forensic investigations. Related studies comparing pictures and phrases have yielded inconsistent results. The present work compared an RT-CKT using verbal phrases as stimuli to one using pictures of faces. This led to equally accurate and efficient tests using either stimulus type. Results also suggest that previous inconsistent findings may be attributable to study procedures that led to better memory for verbal than visual items. When memory for verbal phrases and pictures were equated, we found nearly identical detection accuracies. Copyright © 2007 John Wiley & Sons, Ltd.