Interference causes forgetting relevant information while driving much more strongly than decay

Road crashes remain a major public health issue around the world with an unacceptably high number of people getting killed and injured every day. As previous research has indicated, failures in taking other road users into account may be a major cause for a large proportion of these crashes. Recently it was suggested that in some of these cases drivers had looked at the road users at some point of time but had apperently forgotten about them ('saw but forgot' error). As research on memory indicates, there are two possible reasons for this forgetting: Information may decay in the working memory when too much time has passed. Additionally, information may be replaced by other information added to memory (interference). To examine the role of these mechanisms in forgetting (recall accuracy), an online 8x8 experimental design was used varying the elapsed time since presenting the information (0 to 14 s in 8 steps; decay hypothesis) and the amount of subsequent information since a situation was perceived (0-7 pieces of information; interference hypothesis). A scenario was used similar to driving on the highway with 89 participants. The results of the 8x8 repeated measures ANOVA show that the participants' recall accuracy decreased with an increasing amount of subsequent information but was not significantly affected by elapsed time. Accordingly, one would assume that 'saw but forgot' errors should occur more frequently with more information present, but not with more time passed. From a perspective of traffic safety, critical situations with a large number of information should be especially targeted for prevention measures.