Many research have shown that icons are hard to memorise and are often highly inefficient. The Microsoft Outlook toolbar is a good example: the former icon-only toolbar had poor usability and changing the icons and their positioning didn’t help much. What did help was the introduction of text labels next to the icons. It immediately fixed the usability issues and people started to use the toolbar. In another study, the team of UIE observed that people remember a button’s position instead of the graphic interpretation of the function.

https://uxmyths.com/post/715009009/myth-icons-enhance-usability

Busted!