Dr. Steve Wood describes four psychological concepts that help to explain why some witnesses make mistakes in their testimony performance: 
1) Yerkes-Dodson Law suggests there is a relationship between performance and arousal. Increased arousal can help improve performance, but only up to a certain point. At the point when arousal becomes excessive, performance diminishes. 
2) The Dunning-Kruger effect is a type of cognitive bias in which people believe they are smarter and more capable than they actually are. Essentially, low-ability people do not possess the skills needed to recognize their own incompetence. 
3) Evaluation apprehension is a human tendency to try to look better or the fear of being evaluated. This creates a lot of anxiety because of their concern about how they are perceived by others who are watching them and their performance. 
4) "Thin-slicing" refers to the ability of our subconscious to find patterns in situations and behavior based on very narrow slices of experience or information. 
Watch the video of this episode: https://www.courtroomsciences.com/r/EdX