Does multitasking get harder with age, and is it one skill?
Doing two things at once cost older adults more on some tasks but not others, and the size of the cost on one task barely predicted the cost on another, suggesting multitasking is not a single general ability.
Source
Web-based assessment of dual-task costs at different ages: an analysis across cognitive domains
Study at a glance
- Design
- Cross-sectional — Web-based, self-administered testing across six age bands; within-subject single- versus dual-task load manipulated in three tasks (Trail Making Test A/B, TAP divided attention, MEMO visual memory with auditory secondary task), analysed with mixed models and regressions.
- N
- N=419 · 419 participants retained after outlier, technical and incomplete-data exclusions from 780 who started.
- Population
- Italian-speaking healthy adults aged 18-76 tested online
- Outcome
- Accuracy/efficiency and dual-task costs (percentage change from single to dual task) in each task; relations with age, global cognitive efficiency (Auto-GEMS) and cognitive reserve
Structured fields used in claim comparison tables when every cited study has a complete layer.
What they did
The researchers tested 419 healthy Italian-speaking adults aged 18 to 76 entirely online. Each person did three tasks in easier single-task and harder dual-task versions: a digital Trail Making Test (connecting numbers, then alternating numbers and letters), a divided-attention task monitoring visual and auditory signals, and a picture-memory task done alone or while listening for target letters. They calculated the percentage drop in performance from single to dual task (the dual-task cost) and related it to age band, a short web-based test of global cognition, and a cognitive reserve score based on education, work and leisure.
What they found
Performance fell with age and with added load on all tasks. Dual-task costs grew with age for the Trail Making and memory tasks, but not in a straight line: Trail Making costs were stable until about the 40s and then worsened, while memory costs rose up to around the 50s and then levelled off. Divided-attention costs showed no age effect. Higher global cognition and cognitive reserve were weakly linked to smaller costs, and costs on different tasks were almost uncorrelated, with the largest correlation only about 0.045.
The limits
What it doesn't show
The design is cross-sectional, so age differences could reflect generational differences rather than change within individuals. Testing was unsupervised online, so digital skill, home distractions and compliance were uncontrolled, and people who volunteer for online studies may be more tech-savvy than average. The oldest group was small, and the divided-attention task always ran its conditions in the same order, so practice effects may have hidden load or age effects there. The extracted text lacks the full methods for the Trail Making and divided-attention tasks and the participant section, so some procedural details cannot be checked here.
Key terms
- Dual-task cost
- The drop in performance when doing a task at the same time as a second task, expressed relative to doing it alone.
- Cognitive reserve
- The idea that education, complex work and stimulating leisure build resilience that helps people maintain cognitive performance as they age or face brain changes.
- Trail Making Test
- A test where people connect numbers in order (part A) and then alternate between numbers and letters (part B), used to measure processing speed and cognitive flexibility.
- Task-specificity
- The idea that an ability, such as multitasking, depends on the particular task demands rather than reflecting one general capacity.
- Linear mixed-effects model
- A regression that handles repeated measurements from the same people by modelling both group-level effects and individual differences.
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Quiz yourself
What best summarises how dual-task costs related across the three tasks?
Common questions
If older people are worse at multitasking, why didn't all tasks show it?
Age effects on dual-task costs depended on the task: flexibility and memory tasks showed them, while the divided-attention task did not, though its fixed condition order may have masked an effect.
Why do tiny correlations between tasks matter?
If multitasking were one general ability, people with large costs on one task should have large costs on the others; near-zero correlations suggest each task taps different processes.
Can online tests replace lab tests?
They were feasible and sensitive here, but unsupervised conditions and self-selected, digitally literate volunteers are important trade-offs.
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