Retrospective Think Aloud is a technique used in usability

Usability

Usability is the ease of use and learnability of a human-made object. The object of use can be a software application, website, book, tool, machine, process, or anything a human interacts with. A usability study may be conducted as a primary job function by a usability analyst or as a secondary job...

, and eye tracking

Eye tracking

Eye tracking is the process of measuring either the point of gaze or the motion of an eye relative to the head. An eye tracker is a device for measuring eye positions and eye movement. Eye trackers are used in research on the visual system, in psychology, in cognitive linguistics and in product...

 in particular, to gather qualitative information on the user intents and reasoning during a test. It's a form of think aloud protocol

Think aloud protocol

Think-aloud protocol is a method used to gather data in usability testing in product design and development, in psychology and a range of social sciences...

performed after the user testing session activities, instead of during them.
Fairly often the retrospective protocol is stimulated by using a visual reminder such as a video replay.