google search tab shortcut not working

I often use the "tab" key to quickly browse google search results but recently it stopped working.

usually pressing tab after searching puts a tiny arrow next to the results. this way you can easily use your keyboard arrows to navigate to the one you want.

Solution

This thing was making me crazy lately. Cleaning up cookies as some suggest was not an option as I'm always logged in into my Gmail account. Indeed, I could have switched to Incognito mode to have keyboard shortcuts at my fingertips but for God's sake who would be content with such UX?

So I spent half an hour and finally found that Lou Kosak said in the Google product forums:

Just found a (the?) fix. Turns out tab + arrow keys + enter navigation of search results only works if Google Instant is turned on (see https://superuser.com/a/554324).

To summarize the superuser answer:

go to google.com when logged in
click Settings in the bottom right
click "Search Settings"
update your "Google Instant Predictions" setting to "Only when my computer is fast enough" or "Always show instant results".

Update 2017-07-31: Google has dropped Instant search. See: http://searchengineland.com/google-dropped-google-instant-search-279674. This means that this solution does not work anymore.