The human body uses reaction time during complex situations such as a deer running in front of you and you have to make a split-second decision to swerve or hit the animal . Reaction time can also be used for memory retrieval. Whether you need to remember something for a test or a quick answer to a debate, your reaction time is everything. If you can't locate that information in your memories in time to get the answer, then you will experience a feeling of failure that will be encoded in your mind as a terrible long-term.