Spot the difference: Investigating the effects of ageing on change blindness in QR codes with eye tracking

Humans struggle to notice changes in visual scenes, a limitation called change blindness. Older adults show heightened susceptibility to change blindness, which can affect both decision making and safety. Despite increasing reliance on technology in our environments, change blindness in human-computer interactions is poorly understood. Here we used two experiments to explore change blindness in quick response (QR) codes. Experiment 1 recruited 40 participants who completed a one-shot change detection task incorporating modifications to QR code images. Overall, 65.1% of modifications were identified, and detection performance improved with larger changes (95.9%) compared to smaller changes (34.4%). Experiment 2 recruited 60 younger and 60 older adults to complete the same task, while their eye movements were tracked to measure visual scanning behaviour. We examined whether modifications to QR codes could be detected, and whether detection performance was influenced by age, age-related cognitive factors such as visual working memory, visual scanning behaviour and prior QR-code experience. In total, 64.8% of modified QR codes were identified, with greater detection for larger changes (92.6%) than smaller changes (37.0%). Overall, QR-code experience, visual scanning behaviour, and age significantly predicted detection performance, as older adults (61.5%) detected fewer modified QR codes than younger adults (67.9%). Although larger visual working-memory capacity was a significant predictor of better detection performance when considered in isolation, its effect was no longer significant once QR-code experience, visual scanning, and age were added to the model. This implies change-detection performance is shaped directly by QR-code experience, age, and visual scanning.