Ackerman et al (2013)

• Aim: 

  To investigate how naturally occurring cortisol level changes affect memory performance.
• Method:

  • Correlational study
  • 1225 participants (healthy males and females, 18-35 years old)
• Procedure:

  1. Measured cortisol levels via saliva samples
  2. Participants rated images as emotionally positive, negative, or neutral
  3. Recall tests after 10 minutes and 20 hours
  4. Cortisol measured before encoding, before recall, and after recall
• Results:

  • Lower cortisol levels during recall correlated with better memory performance
  • Cortisol levels during encoding did not predict recall
  • Stronger decreases in cortisol during retrieval associated with better recall
• Conclusion:

  Higher cortisol levels during retrieval hinder recall of episodic memories. Lower cortisol levels or stronger decreases in cortisol during retrieval were associated with better memory performance. Cortisol levels during encoding did not significantly affect recall. The result of the study supports prevoius research, indictaing that higher levels during the process of retrieving memories impair the ability to recall memory.
• Key Strengths:

  • Large sample size
  • Measured natural cortisol levels, increasing ecological validity
  • Included both genders
• Key Limitations:

  • Correlational design can't establish causation
  • Limited age range (18-35)
  • Potential third variable problem