Syntes: Nakata (2015) — amount of spacing has large effects on L2 vocabulary; expanding has a small edge

Källa: Nakata, T. (2015). Effects of Expanding and Equal Spacing on Second Language Vocabulary Learning. https://doi.org/10.1017/S0272263114000825

Verified content

• [abstract] N = 128 Japanese college students studied 20 English–Japanese word pairs under expanding vs equal spacing and massed/short/medium/long amounts of spacing.
• [abstract] Main effect of amount of spacing was significant and produced large effect sizes.
• [abstract] Expanding spacing showed a limited but statistically significant advantage over equal spacing (first L2 study to find that superiority).
• [abstract] Authors conclude introducing spacing may matter more than expanding vs equal schedules.

Limits

• Read level: abstract. Numbers only from what was read; do not use for a ledger verdict until full text is checked where marked abstract-only or secondary.

Why it is in the library

Second verified source for the spaced-L2 candidate (Phase B Near seed).

Added 2026-10-27 by the project (Phase B expansional push). [abstract] = published abstract; [full text] = full text; [assessment] = judgement; [secondary] = secondary summary pending paper check.