Chapter 6: Memory

What is Memory?

  • Memory: Ability to store and retrieve information over time

  • Three key functions of memory

    • Encoding

    • Storage

    • Retrieval

Encoding: Transforming Perceptions Into Memories

  • Memories are made by combining information we already have with new information coming in.

    • Memories are constructed

  • There are three major ways to encode

    • Semantic encoding 

    • Visual imagery encoding

    • Organizational encoding

Semantic Encoding

  • Semantic encoding

    • Process of relating new information in a meaningful way to knowledge that is already stored in memory

    • Uniquely associated with increased activity in the lower left part of the frontal lobe and the inner part of the left temporal lobe

Seminal Encoding: Seminal Research

  • Toronto researcher Fergus Craik and Endel Tulving presented participants with a series of words and asked them to make one of three types of judgements.

    • Semantic judgements

    • Rhyme judgments

    • Case judgements

Seminal Encoding: Seminal Research

  • Toronto researchers Fergus Craik and Endel Tulving presented participants with a series of words and asked them to make one of three types of judgements.

    • Semantic judgements

    • Rhyme judgment

    • Case judgements

Visual imagery encoding

  • Visual imager encoding

    • Process of storing new information by converting it into mental pictures

      • Visual imagery encoding produces neural changes in visual and memory networks that support enhanced memory performance.

      • Smartphone app was used to provide successful training in visual imagery to encode new information.

Organizational encoding

  • Process of categorizing information according to relationships among series of items

  • Current experiences are organised by segmenting the ongoing flow of events into meaningful units.

    • Sorting items into categories is effective way to enhance subsequent recall of those items

Organizing Words Into a Hierarchy

  • All three forms of encoding can used as mnemonics.

Short-term storage and Working Memory

  • Short-term memory (STM): Storage that holds nonsensory information for more than a few seconds, but less than a minute

    • Rehearsal

    • Chunking

    • Working memory

Rehearsal and Chunking Strengthen Memory

  • Rehearsal

    • Process of keeping information in short-term memory by mentally repeating

  • Serial position effect

    • First few and last few items in a series are more likely to be recalled than the items in the middle.

      • Primacy effect

      • Recency effect

      • Von Restorff effect: remember distinctive stimuli

  • Chunking

    • Combining small pieces of information into larger clusters or chunks that are easily held in short-term memory.

Interference

  • Retroactive interference: New memory interferes with older memory

  • Proactive interference: Older memories interfere with new memories

Long-term Memory

  • Explicit (Declarative)

    • Episodic Memories: Memory of a life event, or an “episode” of life.  For example, do you remember when your parents threw you a birthday party? How old were you? Another example is: “What did you eat for breakfast this morning?”

    • Semantic Memories (facts and memories): Memory for knowledge and facts. An example of a semantic memory is knowing the name of our current Prime Minister. Answer: Justin Trudeau.  Another example of a semantic memory is 2 + 2 = 4.  Can anyone give me an example of a semantic memory?


  • Implicit Memories (Non-Declarative):  Some call this “tacit knowledge”.  Oftentimes, we have memories of things we can do very well but cannot describe very well. For example, can you describe how to kick a soccer ball (without using the term kick)?

    • Predurals Memories: memory includes muscle memories of habits, skills and techniques that we have learned through the years. These are skills that we can do, but find difficult to describe. For example, can someone guide me, a guitar novice, on how to play a chord? Where do I put my fingers? What is a fret?

    • Sensitization: repeated stimuli,  increased behavioural response

    • Habituation (Desensitisation): repeated stimuli, decreased behaviour response

    • Conditioning 

    • Priming: Is the phenomenon in which stimuli that are not consciously processed end up affecting our behaviour. For example, let’s play rock, paper, scissors.  We’ll do it this way. 1, 2, 3, Go. Ready? 1, 2, 3, Go.

H.M (Scovile and Milne, 1957)

  • Bilateral hippocampectomy to treat his grand mal epileptic seizures

    • Consequences: 

      • Anterograde amnesia

      • Only explicit memories were affected. For example, H.M. couldn’t remember things like his new doctor’s name. 

Types of Amnesia

  • Anterograde amnesia: inability to form new memories after a trauma or a surgery

    • Finding Dory

  • Retrograde Amnesia. Retrograde amnesia is the inability to “remember” explicit memories (the conscious, intentional recollection of facts and events). 

    • “The Vow” may be a representation of retrograde amnesia. As well, those who have watched the Bourne series will know that Jason Bourne is another example of someone with retrograde amnesia.  Both movies consist of the trope of a person who is injured and wakes up to find themselves with no memory of the “recent” past.


Clive Wearing Video

  • Suffers from Anterograde amnesia

What are some of the similarities between Clive Wearing and H.M.?

Both of them showed hippocampal damage. And both also lost their ability to form new episodic memories.  Both of them retained some of their implicit memories (like procedural memories).


What are some of the differences between Clive Wearing and H.M.?

Clive Wearing lost parts of his frontal lobe, which you can see affected his emotional state. The frontal lobes are involved in conflict management of dissonant, or different, ideas.


What is the capacity for the two types of sensory memory, iconic and echoic memory: The entire sensory field.

What is the capacity for short-term memory: 7+/-2 items

What is the capacity for long-term memory: Somewhat infinite


What is the duration for iconic memory: <1s 

What is the duration for echoic memory: 2-3 seconds

What is the duration of short-term memory without rehearsal: ~18 sec

What is the duration of long-term memory: Lifetime

What is the supporting evidence for iconic memory (both capacity and duration): Sperling’s letter matrices

What is the supporting evidence for short-term memory (both capacity and duration): (Brown) Peterson, and Peterson task.