Ethical Consideration

Ethical Consideration: Informed consent

  • Informed consent in psychology is an ethical principle that ensures individuals are fully aware of and agree to participate in psychological research, therapy, or other professional activities. It involves providing clear, comprehensive, and understandable information about the nature, purpose, potential risks, and benefits of the procedure or study.

Study: HM (Milner, 1966)
Brenda Milner began studying H.M. in-depth in 1957 and formally reported her findings in 1966. She sought to understand the effects of the surgery on his memory and cognitive functions.

Key Findings:

  1. Severe Anterograde Amnesia:

    • H.M. was unable to form new long-term explicit (declarative) memories after the surgery.

    • He could not remember events, people, or information learned after 1953, even after repeated exposure.

  2. Intact Procedural Memory:

    • Despite his inability to form new explicit memories, H.M. could acquire new implicit (non-declarative)skills.

    • For example, in one experiment, Milner taught him to trace a shape while looking at its reflection in a mirror (a challenging motor task). Though he had no memory of practicing the task, his performance improved over time, showing that procedural memory relies on brain structures outside the hippocampus.

  3. Preserved Short-Term Memory:

    • H.M. could hold information in his short-term memory for a brief period, as long as he wasn’t distracted.

    • For example, he could repeat a string of digits immediately after hearing them, but he would forget the sequence after a few moments.

  4. Preserved Pre-Surgical Memories:

    • H.M.’s retrograde amnesia (loss of past memories) was partial. He retained memories from his early life but struggled to recall events closer to the time of the surgery, showing a temporal gradient in memory loss.

  5. Normal Intelligence and Personality:

    • H.M.'s IQ remained average to above average post-surgery, and his personality appeared largely unchanged

  6. Implications of the Study

    Milner's research revealed crucial insights into how memory works:

    1. Localization of Memory:

      • The hippocampus and surrounding medial temporal lobe structures are critical for forming new explicit long-term memories but are not necessary for short-term memory or procedural memory.

    2. Multiple Memory Systems:

      • The study demonstrated that different types of memory (e.g., explicit vs. implicit) rely on distinct brain regions.

    3. Temporal Role of the Hippocampus:

      • The hippocampus does not store memories permanently but is essential for consolidating short-term memories into long-term memories.