Eidetic

Eidetic is a educational game application developed by F-Droid Open Source, packaged as a single Android APK of version 1.4 weighing in at 4.68 MB. The package targets Android 4.1+ and above. Below you'll find the publisher's own description, a quick spec sheet, and a short buyer-beware checklist so you know exactly what you're installing before tapping download.

1. Only download through the button on this page — never from third-party mirrors or shortened links, which are the most common way malware spreads.
2. File size is a light 4.68 MB, so it installs quickly even on modest connections.
3. This build is signed by "F-Droid Open Source" — always verify the developer name matches what's listed on the app's official store page before installing an update.
4. After install, Android may prompt you to allow "Install from unknown sources" — approve only this one install, then revoke the permission in Settings > Apps > Special access.
5. We link directly to the APK file or the publisher's repository; we do not modify the binary. Always run a virus scan after any sideloaded install.

Eidetic is an app for improving and testing your working memory. All you need to do is press the buttons in the right order. It's harder than it looks.

Background

The chimp test, also known as the Ayumu memory test, is a test designed to assess working memory.

It was popularized by a study conducted at the Primate Research Institute of Kyoto University in Japan, where chimpanzees demonstrated remarkable short-term memory abilities.

Chimps seem to, effectively, have a photographic memory (eidetic memory).


Untrained humans generally perform significantly worse than chimpanzees on the chimp test. So, this app trains you. The hope is that we can eventually match or beat chimp records.

Gameplay

• Numbers from 1 to 9 are displayed randomly


• You must memorize the positions of the numbers


• Once you press 1, all buttons display a ?


• You need to then use your memory to press 2, 3,..., 9


• It's game over if you press the wrong button thrice.

Is Eidetic free to download?
Yes. The APK file linked from this page is free. The developer may offer in-app purchases once installed, but obtaining the installer itself costs nothing.

What Android version does Eidetic require?
Android 4.1+ or newer. Installing on older devices may cause crashes or refuse to install.

Is Eidetic safe to install?
We link to the exact APK published by F-Droid Open Source. We do not modify the file. Still, as with any sideloaded app, scan it with a reputable antivirus before opening it, and only grant permissions the app genuinely needs.

How do I update Eidetic?
Install the newer version on top of the old one — Android will keep your data. If the signature differs, uninstall first (you may lose local progress).

Why is the app not installing?
Common causes: not enough storage, an older Android version than 4.1+, or a conflicting build already installed. Free up space, check your OS version, and uninstall any previous copy before retrying.

1. Tap the Download APK button above and save the file to your device.
2. Open your device Settings → Security (or Apps → Special access → Install unknown apps) and allow your file manager or browser to install unknown apps for this one file only.
3. Open the downloaded io.github.hathibelagal.eidetic.apk file from your Downloads folder.
4. Tap Install and wait for Android to finish.
5. Open «Eidetic» by F-Droid Open Source and grant only the permissions it actually needs.
6. Revoke the "unknown sources" permission once you are done installing.

Note: this page hosts or links to the installer only. The application name, icon and description are provided for identification. All trademarks belong to their respective owners.