Dual N-Back: IQ Brain Training (iOS), developer post: what changed after community feedback, and what is free

[Strobolt]

Hello all, developer post, so read with that in mind.

I make Dual N-Back: IQ Brain Training for iPhone and iPad, and since this list has hosted nbacking.com, Eucalculia and others, here is mine, three months after launch and after a round of changes driven by the r/dualnback community.

What it does: dual through hepta n-back (up to seven concurrent streams), N from 1 to 15, per-stream accuracy, full session history, spoken letters in the user's own language, and a "lab" of 12 short cognitive tests (chimp test, Stroop, reaction time, span tasks) with Game Center leaderboards so you can track something repeatable every couple of weeks.

What is free: the whole lab, the history, and three n-back sessions a day at N=1 and N=2. N=3 and above plus the extra modes are paid (monthly, yearly with a trial, or a one-time unlock). In August I put part of the lab behind the paywall; it was the right complaint from users and it is free again.

On evidence, since this group has debated it since 2008: I present it as a hard working-memory exercise, not as an IQ raiser. Near transfer is well supported; far transfer to intelligence measures is small or absent in the meta-analyses (Au et al. 2014, https://doi.org/10.3758/s13423-014-0699-x; Melby-Lervag, Redick & Hulme 2016, https://doi.org/10.1177/1745691616635612).

App Store: https://apps.apple.com/us/app/dual-n-back-iq-brain-training/id6775563998

Two questions for people who have trained for years: what stimulus interval do you consider real training (several users asked for a manual interval instead of the automatic one tied to the level), and would a shared leaderboard on dual n-back itself be useful or a bad incentive?

Romeo