Conversation Limits Attention: The Impact of Conversation Complexity Paul Atchley and Jeff Dressel University of Kansas Introduction The risk of conversing on a cellular phone while driving is well documented (Cain & Burris, 1999; Strayer, Drews, and Johnston, 2003). Atchley and Dressel (2004) have suggested that the Useful Field of View (UFOV) is a possible mechanism by which this risk can be explained. Few studies have been conducted to investigate the aspects of conversation that can lead to this interference effect. These experiments investigate two common types of conversational material, directional and emotional, and compare their relative interference effects. General Method The Useful Field of View test consists of three subtests: discrimination, divided attention, and selective attention. Participants completed each UFOV test in each experiment alone, as well as while performing a concurrent conversational task which served to simulate cellular phone use. Presentation time thresholds were determined by an adaptive staircase. Experiment One The UFOV tests were administered with and without a concurrent conversational task. The concurrent conversational task used in this experiment required participants to listen for a given “vertical plane” directional term (e.g., upper right, left), and to respond with the congruent cardinal direction (e.g., Northwest, West). Results Each increasing level of difficulty in the UFOV test yielded significantly larger presentation time thresholds, F(2,38) = 30.8, p<.001. There was a significant main effect of the dual-task presence, F(1,19) = 45.8, p<.001. The interaction of these variables was significant, F(2,38) = 5.5, p<.01. When the concurrent conversational task was being performed, each increasing level of the UFOV task yielded greater increases in threshold than when the UFOV task was performed alone. (See below) Experiment Two The concurrent conversational task used in this experiment required participants to respond to a given word with a word that began with the final letter of the given word, as in Atchley and Dressel (2004). Participants heard one of two classes of words: positive emotional valence, or negative emotional valence. Results A pattern of results consistent with Experiment One was observed (I.e., main effects of UFOV level, dual-task presence, and interaction, ps<.01). Overall, the size of the interference efects for this experiment are the laregest we’ve found, though only by mariginal significance (p=.056 for one planned comparison). (See below). However, when only negative valence words are analyzed, the interference is the largest we’ve seen, significantly larger then those reported in Atchley and Dressel (2004). (See right). Discussion All conversational tasks employed in these experiments yielded large effects on the presentation time required to perform basic visual attention tasks (here, a five-fold increase in thresholds). The directional conversational task interference could be due to the similarity of the information (I.e., directional) required to perform both the conversation and vision tasks (Wickens, 2002). The emotional conversational task interference was (for negative emotion) the greatest we’ve found. This is consistent with a long history of work on attention and emotion (e.g., Easterbrook, 1959). References Atchley, P., & Dressel, J. (2004). Conversation limits the Functional Field of View. Human Factors, 64, 644-673. Cain, A. & Burris, M. (1999). Investigation of the use of mobile phones while driving. Report of the Center for Urban Transportation Research. Easterbrook, J.A. (1959). The effect of emotion on cue utilization and the organization of behavior. Psychological Review, 66, 183-201. Owsley, C., Ball, K., McGwin, G., Sloane, M.E., Roenker, D.L., White, M.F., & Overley, T. (1998). Visual impairment and risk of motor vehicle crash among older adults. Journal of the American Medical Association, 279, 1083-1088. Strayer, D., Drews, F., & Johnston, W. (2003). Cell-phone induced failures of visual attention during simulated driving. Journal of Experimental Psychology: Applied, 9, 23-32. Wickens, C.D. (2002). Multiple resources and performance prediction. Theoretical Issues in Ergonomics Science, 3, 159-177. Sample screen of the UFOV test.