The investigation consisted of well controlled lab experiments- the researched carefully controlled the IV (verb used) and the effect it had on the DV (estimated speed, and yes or no to broken glass). Extraneous variables could be controlled, eg ages of participants, use of the fimled crash which made it less likely that the DV was affected by confounding variables, so cause and effect could be established.
--The study can also be easily replicated, due to the standardised procedure used. This means this if similar results are obtained, we know the study is reliable.
--The findings are supported by other experiments into EWT, which confirms that leading questions distort memory.
-- However, the study took place in an artificial environment, which makes the ecological validity of the study questionable. The car crashed viewed were different from the…