1. What is the serial position effect, and what is the evidence for it and against it?
2. What is the duration, capacity, and coding of the long-term store (LTS)?
3. Explain the differences between implicit and explicit memories.
4. How does Tulving categorize different kinds of memory?
5. What does amnesia reveal about memory?
Glanzer & Cunitz (1966):
• _______ effect: better recall for items at beginning of list
- greater rehearsal causes transfer to LTS
• _______ effect: better recall of items at end of list
- items still in STS
- mental math (recall delay) affected recency only
Problems:
__________ of STS & LTS
- coding: both use acoustic, visual, and semantic
- forgetting: due to interference
argument from _________
- memory varies along a continuum (short--long)
- why have different memory systems?
- simpler to assume one memory system
Craik & Watkins (1973): STS to LTS transfer
- participants heard a list of items; had to remember last word starting with “g”
e.g., daughter, oil, rifle, garden, grain, table, football, anchor, giraffe
- words differed in opportunities for rehearsal
e.g., giraffe value = 0; grain value = 4; garden value = 1
- participants did math task, then free recall of all words
- memory for “g” words:
- no advantage for greater _________
Bekerian & Baddeley (1980): role of repetition
- BBC advertised new radio frequencies 10×/hour
- casual listener exposed to message 1,000×
- most listeners didn’t ________ the message
- repetition ≠ retention
• _________ (or infantile) amnesia: adults’ inability to remember events before ages 3-5
- average age of earliest memory is ˜3.5 years of age
- females report earlier memories than males
- recall of memories over the lifespan falls off before age 8 compared to other periods
- Freud (1916): “the remarkable amnesia of childhood” is due to repression of traumatic experiences of early psychosexual development
- contemporary theories:
▸ ___________ (involved in storage of long-term memories) not sufficiently mature before age 2
▸ incomplete language development is a barrier to encoding autobiographical memories (which include episodic and semantic components)
▸ episodic memories are tied to one’s sense of ____, which develops later in life
• Bahrick, Bahrick, & Wittinger (1975):
- studied retention of names and faces of people’s high school classmates (vs. strangers)
- __________: very long-term storage that canlast your entire life
• Von Neumann (1958):
- calculation based on neural firing rate, estimated number of neurons, and a lifetime of 60 years
- 2.8 × 1020 bits, or about 1 exabyte (1 billion gigabytes)
• Landauer (1986):
- estimated “functional information content”: amount of information adults need to do normal tasks
- compared rate of information processing vs. forgetting on a number of tasks
e.g., reading, pictures, nonsense syllables
- people retain 2 bits/sec
- conclusion: adult LTS contains 109 bits, or 125 megabytes
- not the same as storage ________
• Reber (2010):
- the brain has ~100 billion neurons--but not all are involved in forming long-term memories
- ~1 billion neurons likely participate in memory × ~1,000 synapses each = 1012 (1 trillion) total synapses
- but each synapse does not store one memory
- rather, memories are ___________ across our brain’s neural networks, exponentially increasing capacity
- memory capacity estimated to be 2.5 petabytes (2.5 million gigabytes)
• bottom line: LTS capacity unknown; practically _________
• Shulman (1972):
- found that falsely recalled words had a similar _______
e.g., “baby” for “infant”, or “ship” for “boat”
- depended on position of list item: semantic confusions at _____ (words in LTM), acoustic confusions at ___ (words in STM)
- words that were held in LTS were coded by meaning
• ________ memory (a.k.a. declarative memory): conscious, intentional remembering of knowledge or an event
- ______: reproducing previously encountered information from memory
- ___________: identifying previously learned information
• ________ memory (a.k.a. nondeclarative memory): unconscious retention due to previous experience
- __________ _______ effect: previous experience with a stimulus facilitates later response to the same (or similar) stimulus
e.g., word-fragment completion: fill in missing letters from a word: P__M_S__RE
e.g., word-stem completion: given the first few letters in a word, complete the word as fast as possible: “per...”
Endel Tulving (1972, 1985):
• ________ memory
- memory for events that occurred in your life
- tied to specific learning episode or experience
• ________ memory
- stores words, concepts, rules, abstract ideas
- general knowledge not tied to any experience
• __________ memory
- underlies motor & cognitive skills
- e.g., doing math, playing chess, riding a bike
Evidence:
- certain patients with amnesia may have damaged one kind of memory system but have other ones intact (this is a ____________ effect: one specific ability is affected, but another is not)
• __________ amnesia: inability to remember events that occurred before a traumatic event
• ___________ amnesia: inability to form new memories of events that occurred after a traumatic event
The case of patient H.M. (Scoville & Milner, 1957; Corkin, 2013):
- had progressive uncontrolled epilepsy since age 10
- to control his seizures, had bilateral medial temporal lobe (MTL) resection at age 27 (in 1953)
- ___________, parahippocampal gyrus, and amygdala removed
- surgery was successful (fewer seizures), but resulted in profound amnesia
- normal IQ, STS (e.g., digit span), language (speech, writing, and reading)
- could remember events/facts in his distant past, but had __________ ______ retrograde amnesia for events 11 years before the surgery
- could not learn new facts or remember information about events since his surgery:
• could not find new home, even after 10 months
• language frozen in the _____
• forgot who he was talking to if he turned away
- however, he could form new __________ memories (e.g., mirror tracing task), but had no conscious recollection of previous training episodes
- see also Memory’s Ghost: The Strange Tale of Mr. M. and the Nature of Memory (Hilts, 1995) and Permanent Present Tense: The Unforgettable Life of the Amnesic Patient, H.M. (Corkin, 2013)
The case of patient K.C. (Moscovitch, Schacter, Tulving & colleagues, 2005):
- suffered a closed-head injury in a motorcycle collision in Toronto at age 30
- severe damage to MTLs and almost complete bilateral ___________ loss
- left-hemisphere lesions to posterior occipital-temporal and anterior frontal-parietal cortices
- personality changed from outgoing to more tranquil
- had retrograde amnesia for episodic memory, although ________ knowledge was intact
- also had some anterograde amnesia: no episodic memories formed after the accident (________ amnesia)
- but could form new semantic and procedural memories:
• played chess but did not remember playing a game
• knew where family cottage was but did not remember ever going there
• learned the Dewey decimal system for his job at the library, but did not know when he learned it
Conclusions:
• unimpaired STS implies it is biologically _________ from LTS
• hippocampus (and MTL?) not a storage site, but important for _____________ of explicit memories (STS to LTS transfer)
• H.M. provides evidence that implicit memory is ___________ from explicit memory
• K.C. provides evidence that, within ________ memory, semantic memory is dissociated from episodic memory