Split-level head

It wasn’t long ago that psychologists considered memory to be a single-thread of stimulus-response associations; strengthened by repetition. What happened between the time information was entered and retrieved was terra incognito. Memory was commonly thought to be a passive record of events. Once information was stored, it became a reliable part of memory. It was always there; forgetting was blamed on a failure of retrieval. These principles of memory no longer apply. They fail to explain clinical reports of patients with aphasia or Alzheimer’s. Aphasia patients, for instance, can usually remember current events, but they forget long-term information such as the meaning of words or the names of familiar objects. On the other hand, Alzheimer’s patients can usually remember long-term information, such as the meaning of words, but they forget recent events such as a visit by a relative or their arrival at the clinic. These observations suggest different types of memory at work. Some temporarily hold events in our immediate surroundings while others preserve them on a more lasting basis.

Memory is now considered to be like a multi-level interchange. It has many locations, and each location has it’s own shelf-life. Instead of being a passive record of events, memory is more like an active participant constructing events. When listening to someone speak, for instance, sound enters sensory storage, which has finite capacity for registering immediate impressions, but decays within milliseconds ..allowing just enough time for the sound to be parsed into phonemes. Phonemes are transferred to short-term memory where sentences are constructed and their meaning identified. Meaning is then encoded and transferred to long-term memory based on its perceived informative-value (feelings, relevance, consequences, etc). Although long-term memory is what we traditionally think of as durable memory; it is not as reliable as once thought. Instead of being a passive record of things past, it is more like an active construction-site, integrating and revising things past, present and future (predicted). Dr. Elizabeth Loftus offers compelling evidence for this when she writes about the effect of interrogation and publicity on eyewitness testimony. She’s a good read on the state-of-the arts, if you’re interested.

Presented at a seminar in ~> Cognitive science