Divided attention
Also known as: multitasking, dual-task performance
Divided attention is the ability to distribute limited attentional resources across two or more tasks at the same time. It succeeds when at least one task is automatic and breaks down when both require conscious, controlled processing.
Divided attention is the counterpart to selective attention. Selective attention describes focusing on one stimulus while filtering out others; divided attention describes spreading attention across several stimuli or tasks at once. Both operate under the same constraint — attention is a limited resource — which is why performance on one task tends to degrade as the other demands more.
Whether divided attention works depends on the kind of processing each task requires. Automatic processing is fast, effortless, and developed through practice; it consumes almost no attentional capacity, which is why an experienced driver can hold a conversation while steering. Controlled processing is slow, effortful, and conscious, and it monopolizes resources; navigating an unfamiliar city while doing mental arithmetic quickly overwhelms capacity. Tasks that use different sensory modalities and different response systems also interfere less with each other than two tasks competing for the same channel.
Research on this topic gave psychology several classic paradigms. Dichotic listening studies, in which different messages are played to each ear, demonstrated that unattended information is not fully discarded — the cocktail party effect, where your own name pulls attention from an ignored conversation, shows that some processing continues outside awareness. Dual-task experiments quantify the cost of splitting attention, and they consistently show that what people call multitasking is usually rapid task switching, which carries a measurable performance penalty in both speed and accuracy.
The MCAT tests divided attention in the psychological, social, and biological foundations of behavior section. Be prepared to contrast divided with selective attention, to identify automatic versus controlled processing in a described scenario, and to interpret research findings from dichotic listening and dual-task studies.
Key takeaways
- Divided attention is the distribution of limited attentional resources across two or more simultaneous tasks.
- It contrasts with selective attention, which focuses on one stimulus while filtering out others.
- Automatic, well-practiced tasks can be combined easily; two tasks requiring controlled processing interfere with each other.
- Tasks using different sensory modalities compete less than tasks using the same one.
- Much apparent multitasking is actually task switching, which costs both speed and accuracy.