Final answer:
The described phenomenon where eyewitnesses' recall is altered by post-event information is known as the misinformation effect the correct answer is (a), extensively studied by Elizabeth Loftus.
Step-by-step explanation:
The scenario described where eyewitnesses' memories of a car's speed are influenced after hearing a television report is an example of the misinformation effect. This psychological phenomenon occurs when a person's recall of episodic memories becomes less accurate due to post-event information.
Cognitive psychologist Elizabeth Loftus' research has demonstrated that exposing individuals to new information after an event can lead to alterations in their memory of the original event, as seen when the verb in a question, like 'smashed' versus 'contacted', affects the eyewitnesses' speed estimates and their false recollection of seeing broken glass.
The correct answer is (a) The misinformation effect. The scenario described in the question is a classic example of the misinformation effect.
The misinformation effect refers to the phenomenon where the introduction of false or misleading information after an event can alter a person's memory of that event.
In this case, the television report suggesting that drugs may have contributed to the accident influenced the eyewitnesses' memories, causing them to remember the driver traveling at a faster speed than he actually was.