Here is the aim, procedure, and results of McGaugh and Cahill's study (1995) in detail:

Aim:

McGaugh and Cahill aimed to investigate the role of adrenaline and the activation of the amygdala in the formation of emotional memories. The researchers wanted to determine how emotional arousal influenced memory recall and whether the release of adrenaline played a key role in enhancing the storage of these emotional memories.

Procedure:

• Participants: The study involved participants who were divided into two groups, each group being exposed to a different version of a story accompanied by 12 slides.
• Story Conditions:
  • Group 1: This group heard a "neutral" story. The story was relatively mundane, describing a mother and her son visiting the father at a hospital where they witnessed a simulated disaster preparation drill.
  • Group 2: This group heard a "traumatic" story. The story involved the son being severely injured in a car accident, where his feet were severed. The boy was rushed to the hospital, where surgeons reattached his limbs, and he stayed in the hospital for some weeks before going home with his mother.
• Memory Test:
  • Two weeks later, participants were called back and given a recognition task to test their memory of specific details from the story. The task involved a series of multiple-choice questions related to the slides. For example, participants were asked questions like, "What was the job of the boy's father in the story?" with answer choices such as A. A janitor, B. A lab technician, and C. A surgeon.
• Follow-up Study:
  • In a follow-up study, the procedure was repeated with one variation: participants in the "traumatic" story group were injected with propranolol, a beta-blocker that interferes with the release of adrenaline. Propranolol was used to block the activation of the amygdala, which is crucial for the formation of emotional memories.

Results:

• In the original experiment, participants who heard the emotionally arousing, traumatic story demonstrated better recall of specific details from both the story and the slides. They were able to remember more details compared to the group that heard the neutral story.
• In the follow-up study, participants who had received the beta-blocker (propranolol) and heard the traumatic story performed no better than those who had heard the neutral story. This indicated that blocking the release of adrenaline and preventing the activation of the amygdala resulted in no enhanced memory for emotionally arousing events.

Conclusion:

The study concluded that adrenaline and the activation of the amygdala play a significant role in the creation of memories linked to emotional arousal. The emotionally arousing story, which triggered the release of adrenaline and activated the amygdala, led to better recall of specific details, whereas blocking adrenaline with propranolol prevented this enhanced memory formation. Therefore, adrenaline has a key function in strengthening memories associated with emotional experiences.