A systematic review of task-switching in healthy older adults: paradigm manipulations and switch costs

It is widely accepted that task-switching performance changes in later-life, but it is currently unclear how differences in measurement accrued over almost one hundred years may be affecting our understanding of task-switching performance differences in young versus older adults. This review investigated the different manipulations used in task-switching paradigms with healthy older adults (age 59–97 years), and the impact of these differences on task-switching performance. A search across four databases resulted in 73 articles meeting the inclusion criteria. We found considerable variability in how task-switching in later-life was operationalised, with increasing complexity in paradigm design over time. Digit tasks were the most common task-switching task, and word-cued switching was the most common switch instruction. Larger switch costs were correlated with complex stimulus features, task environments with less informative cues, and shorter preparation time between trials. Most studies comparing young and older adults have found that task-switching was slower and less accurate in older adults. However, conclusions were limited by substantial under-reporting of non-significant results. Future research with better consistency in reporting is needed to clarify whether paradigm manipulations impact the fundamental goal of accurately capturing the costs of switching when using task-switching paradigms in healthy young and older adults.