Limit the number of novel items per session

Introduce no more than 5–7 genuinely new concepts in a single learning session.

Why it works

Working memory holds a fixed number of items; when it overflows, items are lost rather than encoded into long-term memory. Keeping novel input below the capacity ceiling ensures that each item can be processed, related to existing knowledge, and given a reasonable chance of consolidation — rather than being displaced by the next incoming item.

How to do it

1. Before a study session, count how many truly novel concepts it introduces.
2. If the count exceeds 7, split the session and study the remainder the next day.
3. Interleave new items with familiar items so working memory can rest on known material.

Evidence

Miller (1956) identified a working memory capacity of 7 ± 2 chunks — still the most cited figure in cognitive psychology. Later work (Cowan, 2001) suggests the true capacity for pure working memory is closer to 4 items; the higher figure includes memory aids like rehearsal and chunking itself. (observational)

The exact number varies with chunk size, domain familiarity, and available memory aids; "5 to 7 novel items" is a practical heuristic, not a precise universal limit.

Sources

• Miller, G.A. (1956), "The magical number seven, plus or minus two," Psychological Review
• Cowan, N. (2001), "The magical number 4 in short-term memory," Behavioral and Brain Sciences

Common mistake

Judging session length by time ("I studied for two hours") rather than by cognitive load — a two-hour session on wholly unfamiliar material overloads working memory far before the time is up.