Detection of changes through visual alerts and comparisons using a multi-layered display

The Multi-Layered Displays (MLD) comprise two LCD screens mounted one in front of the other, allowing the presentation of information on both screens. This physical separation produces depth without requiring glasses. This research evaluated the utility of the MLD for change detection tasks, particularly in operational environments. Change Blindness refers to the failure to detect changes when the change happens during a visual disruption. The literature equates these visual disruptions with the types of interruptions that occur regularly in work situations. Change blindness is more likely to occur when operators monitor dynamic situations spread over several screens, when there are popup messages, and when there are frequent interruptions which are likely to block the visual transients that signal a change. Four laboratory experiments were conducted to evaluate the utility of the MLD for change detection tasks. The results from the experiments revealed that, when depth is used as a visual cue, the depth of the MLD has a different effect on the detection of expected changes and unexpected events. When the depth of the MLD is used as a comparison tool, the detection of differences is limited to translation differences in simple stimuli with a white background. These results call into question previous claims made for the MLD regarding operational change detection. In addition, observations and interviews were used to explore whether change blindness occurred in an operational command room. The results suggested that operators develop strategies to recover from interruptions and multitasking. These results call into doubt the wisdom of applying change detection theories to real world operational settings. More importantly, the research serves as a reminder that cognitive limitations found in the laboratory are not always found in real world environments.