Update README.md

Author: jackbrookes

README.md

@@ -108,7 +108,7 @@ The settings is cascading, allowing setting independent variables at a `Session`
 
 ### UI
 
-A UI is available (but optional) allowing loading of participant data from file (or add new participant data). Variables that are collected are customisable and can be used in the experiment (e.g. a parameter for a participant's age could be used to change the difficulty of the experiment).
+A customisable user interface is optionally available to collect demographic data and present instructions to the user or experimenter. Variables that are collected are customisable and can be used in the experiment (e.g. a parameter for a participant's age could be used to change the difficulty of the experiment).
 
 <p align="center">
   <img src="media/uxf-ui.png" width=500>