One cognitive process that involves questioning of reliability is memory, it should be questioned because there are many factors that can affect it, for example: social activity, medical diseases/disorders, emotional problems etc. Eyewitness testimony (EWT) is a legal term, that refers to an overview given by people of an event they have witnessed. In cognitive psychology EWT is an important area of research that can give insight to human memory. In this answer we are going to evaluate to what extent is eye-witnessing testimony reliable, using relevant research studies by Loftus & Palmer (1974) and by Yuille & Cutshall (1986).
