Driving Distraction Research


by Sachi Mizobuchi, David Canella

Background & Motivation

• Emerging information and communication technologies give automobile drivers access to  all kinds of information (for navigation, communication, entertainment, etc.)
• Interacting with all this information may distract drivers from the driving task, creating potential safety hazards.
-> How can we implement communication technologies in cars without significantly increasing risk?


• To understand how human cognition & performance changes in multi-tasking (i.e., driving and interacting an information system) conditions.
• To provide UI design guidelines and design proposals based on relevant scientific results.


Divided attention and distraction in multitasking situations are related to the availability of attentional resources in the context of different combinations of perceptual, storage, and motor modalities.

Attentional resources are related to working memory.  Baddeley’s (1986) influential model of working memory assumes a Central Executive (CE) as the supervisory attentional system which is responsible for the selection, initiation, and termination of processing routines (e.g., encoding, storing, retrieval). In this research, we examine three prominent (among several that have been proposed) central executive functions,  namely “inhibition”, “shifting”, and “updating” (Figure 1), based on the characterization by Miyake et al. (2000).


Figure 1. Working memory and fractionated central executive model

Figure 2 shows the hypothesized relationship between CE functions and cognitive workload. As with other models of workload, workload is assumed to increase as available resources becoming insufficient to meet rising task demands. When a CE function is overloaded, the effect will be appeared in poorer performance.


Figure 2. Individual cognitive ability and experienced workload

We assume that workload experienced by individuals is defined as the interaction between individual differences and task requirements. Figure 3 represents our approach, where workload is attributable to task loadings on the three CE functions of inhibition, shifting, and updating. The model makes the following three assumptions:
– Individual differences exist in the capacity of each CE function;
– Different tasks load the CE to varying extents as a function of both the nature of the task itself and the unique effect of the task on each individual.


Figure 3. Models of cognitive workload based on the individual differences and different task requirements

We expect that examination of specific CE functions will allow a more fine-grained analysis of mental (cognitive) workload. Individuals with different cognitive ability should differ in terms of their susceptibility to different types of workload. Based on findings in the research literature, some people have higher shifting ability than others (and there are also differences in inhibition and updating ability) likely leading to differing abilities to handle multi-tasking situations.

In cases where device operation tasks have different levels of requirement for each of the CE functions we would expect levels of cognitive workload on each function to reflect the extent to which available levels of CE functions within the driver fail to meet the task requirements for those functions.


We set up multitasking experiments with a simulated driving or simplified driving-related task (such as target detect-response task or pedal tracking task for longitudinal control) and a variety of CE tasks. We obtained initial results concerning the impact of cognitive abilities and different multi-tasking contexts on the ability to perform driving related tasks and on experienced workload.

For more details and results & findings, please see our publication:

  • Mizobuchi, S., Chignell, M., Dilange, T. and Ho, W. (2014) Sensitivity of a Voluntary Interruption of Occlusion Measure to Cognitive Distraction During a Pedal Tracking, To be published in Proceedings of the Human Factors and Ergonomics Society Annual Meeting, October 2014 (HFES2014) [Please send email to request a copy]


  1. Baddeley, A.D. (1986) Working Memory. Oxford: Clarendon Press.
  2. Baddeley, A. D. (2003) Working Memory: Looking back and looking forward. Nature Reviews Neuroscience, 4 (10): 829-839.
  3. Miyake, A., Friedman, N. P., Emerson, M. J., Witzki, A. H. & Howerter A. (2000). The unity and diversity of executive functions and their contributions to complex ‘‘Frontal Lobe’’ tasks: A latent variable analysis. Cognitive Psychology, 41,  49–100.