| Although there is empirical evidence that conversation impairs driving performance, the cognitive mechanisms that mediate this relationship remain underspecified. One possibility is that conversation impairs driving by reducing a driver's situation awareness (SA). Johannsdottir and Herdman (2010) reported that a phonological working memory task decreased driver SA for vehicles located behind them while a visuospatial task impaired SA for vehicles ahead. It was hypothesized here that because conversation taxes the phonological loop, SA would be reduced for cars behind the driver. Participants completed 20 trials in a medium-fidelity driving simulator. The screens were blanked 40 -- 60 s into each trial and participants estimated the positions of other vehicles. The driving impairments caused by conversation (e.g., SA for location of other vehicles) were greater for vehicles located behind the driver than for those in front. These findings suggest that conversation impairs drivers' SA by taxing working memory's phonological loop. |
