The Effect of Repeated Cue Exposure on Post-Completion Errors

The Effect of Repeated Cue Exposure on Post-Completion Errors Maartje G. A. Ament (m.ament@ucl.ac.uk) Anita Y. T. Lai (anita.y.t.lai@gmail.com) Anna L. Cox (anna.cox@ucl.ac.uk) UCL Interaction Centre University College London Gower Street London, WC1E 6BT United Kingdom Abstract investigated the role of motivation in the occurrence of post- completion errors. They found that motivation to avoid them does not lead to lower error rates on the post-completion (PC) step. In a similar study, Byrne and Davis (2006) investigated the effect of a number of interventions on the PCE, includ- ing motivation, retraining and redesign. They found that only redesigning the interface resulted in the complete elimination of PCEs, while reprimanding, praising or retraining partici- pants was not more effective than the control condition with no interventions at all. Another mitigation strategy that has seen recent investiga- tion is the use of visual cues. Chung and Byrne (2008) studied the effectiveness of a number of visual cues in reducing post- completion errors. They found that a red singleton onset ap- pearing just before the PC step was not effective in reducing the number of PCEs. However, a more aggressive cue with blinking arrows pointing at the PC button achieved the com- plete elimination of PCEs. Byrne (2008) further investigated the properties a cue must possess in order to be effective. He found that the most important attributes of a successful visual cue are, in order of importance: appearing just-in-time, being specific, and being salient. However, while visual cues can be effective in reducing slips, they also have their drawbacks. Ratwani, McCurry, and Trafton (2008), for instance, argued that cues can become less effective over time, and repeated exposure to them can be an- noying. To address these issues, they developed a real-time system that uses eye movements to predict when an error is likely to occur. This allowed them to provide a cue only when needed, reducing some of the concerns associated with visual cues. Ratwani and Trafton (2009) reported that this system is very effective in reducing error rates. Byrne (2008) highlighted another potential drawback of the use of visual cues. He argued that providing repeated cues may lead people to become dependent on the cue to remem- ber a particular step. This could be problematic in situations in which the cue fails, such as when loud traffic noise masks the ATM beeping sounds upon returning the card, or when a user uses a different device to perform a task which does not provide cues for the same steps. It is possible that, if people learn to rely on repeated cues, they become particularly prone to errors on the cued step, beyond what is expected of a user Slip errors in routine procedures are notoriously difficult to eliminate. They are not the result of a lack of knowledge, so retraining or increasing motivation is not effective. Recently, a number of studies have used visual cues in an attempt to re- duce post-completion errors. These slip errors occur when the last step in a task is forgotten after the main goal has been com- pleted. Visual cues have been shown to be effective in reduc- ing post-completion errors if sufficiently aggressive. However, concerns have been raised over whether repeated exposure to visual cues may lead people to rely on them, and therefore be- come more prone to errors should the cue inadvertently be un- available. Alternatively, people may anticipate the appearance of the cue, which may have a positive effect on error rates. We report on an experiment that tests the effect of repeated exposure to a strong visual cue on the post-completion error rate. Participants were repeatedly exposed to an aggressive vi- sual cue just before the post-completion step, and this cue was withdrawn on a number of target trials. Our results show that error rates on these non-cued target trials are similar to those of non-cued control participants. Moreover, eye-movement pat- terns are similar for target and non-target trials. These results suggest that participants do not become over-reliant on the cue, while they partially support the hypothesis that participants an- ticipate the appearance of the cue. As such, visual cues are a safe and effective way to reduce slip errors. Keywords: Human error; routine procedural action; visual cues; post-completion error; eye-tracking; slip errors. Introduction Despite having the correct knowledge, people still make er- rors while executing routine procedures. Often, these slip er- rors are inconsequential, but in safety-critical domains such as aviation, medicine and nuclear power plant operations they can have severe consequences. While slip errors occur only occasionally, they are nevertheless persistent. They do not occur as a result of a lack of knowledge, and this makes them difficult to eliminate, or even reduce (e.g. Byrne & Davis, A growing body of empirical work has studied these cog- nitive slips in the laboratory. For instance, Byrne and Bo- vair (1997) argued that the post-completion error (PCE), an error that occurs when the last step in a procedure is forgot- ten after the main goal has been completed, is a result of a failure of working memory. They found that a higher work- ing memory load could increase the occurrence of the PCE. More recent research has focussed on how to reduce these errors. Back, Cheng, Dann, Curzon, and Blandford (2006)