In this study conversation with a remote person (hands-free phone), an in-vehicle person (passenger), and a no conversation (baseline) condition were compared on measures of attention and peripheral detection. We held conversation pace constant so that any difference found in attention or peripheral detection could be attributed to the distinctive feature of the type of conversation (remote, in-vehicle). The difficulty level of the verbal task was included as a second independent variable. Forty-eight undergraduate students participated in all conditions of a within-subjects design. The results revealed that conversation resulted in slower reactions and fewer correct responses on both attention and Peripheral Detection tasks compared to no conversation, while conversation type (remote/in-person) did not make a significant difference. Difficulty of the verbal task affected performance on the Peripheral Detection task but not on the attention task. These findings imply that conversation has a negative effect on attention and peripheral detection which are important components of driving. This effect may be greater with difficult conversations. (c) 2005 Elsevier Ltd. All rights reserved.