divided attention

Meaning: Divided attention is processing two or more inputs, or doing two or more tasks, at once, such as driving while holding a conversation. Capacity models treat attention as a limited pool of mental resources. Each task draws on the pool, so when the combined demand exceeds the supply, performance on one or both tasks suffers. Controlled processes (new, effortful, requiring concentration) use a lot of the pool. Automatic processes, built by practice, use little, so they can often be paired with another task at small cost.

On the MCAT: A passage describes a dual-task experiment, for example participants tracking a moving target while also repeating spoken digits. You are asked to predict which condition gives slower reaction times or more errors. Expect worse performance in the dual-task condition than in the single-task condition. Two tasks that use the same modality or resource (two verbal tasks) usually interfere more than two that use different ones. Practice reduces the cost.

Common confusion: Students mix up divided and selective attention. Selective attention is focusing on one stimulus and filtering out others. Divided attention is trying to handle several at once. Also, apparent multitasking of two demanding tasks often involves rapid switching between them, and each switch costs time and accuracy.