Outline

• • Ebbinghaus & the 263: Introduction to • The forgetting curve in the real world Cognitive Processes • Why do we forget? – Consolidation theory Forgetting, and – (decay vs. interference) – Functional – Retrieval failure

Hermann Ebbinghaus (1850 - 1909) Forgetting • Bottom up, episodic approach to studying memory and forgetting • Memory is not perfect, we need to give ourselves room to forget • Learned lists of 13 nonsense syllables • Is a “perfect” memory really desirable? • Forgetting is necessary but seems troublesome because we only notice we’ve • Re-tested himself in intervals ranging from forgotten something when we need it again 20 minutes to a month later • Why do we forget names/faces, punchlines to jokes, etc. • Recorded amount of time to relearn the list (savings method)

The forgetting curve in the real world • Problem with Ebbinghaus…learned nonsense material • Does Ebbinghaus’ forgetting function generalize to more real world material? – Names/faces % – Foreign Mean – Motor skills Savings – Bahrick and colleagues – Linton:

• Do we really know anything about forgetting? • On these graphs, don’t pay to specific numbers, just compare the overall pattern to Ebbinghaus’ function Bahrick et al.: Memory for names and faces of high school classmates Names/faces

• Multiple memory tests (name/picture recognition, name matching, picture matching/cueing, free ) • Strong memory up to 25 years after graduation • Only slight forgetting with recognition measures • Large forgetting after 50 years (not sure if this is due to age or time)

Bahrick: College Professors memory for names/faces of students Names/faces

• College teachers memory for names/faces of former students • Forgetting is more linear in nature than logarithmic • Memory is quite good on recognition measures

Bahrick: Memory for a foreign (that is rarely used) Memory for foreign languages

• Looks a bit like Ebbinghaus’ curve (initially) but much less pronounced • Level to which language was initially learned is an important determinant of what is forgotten • Pretty good memory years later even if it had been used infrequently • Don’t believe this? Learn French, years later, try to learn Spanish How about memory for motor skills: CPR Complex skills

• CPR – forgotten at a rate strikingly similar to the Ebbinghaus curve even though it’s an extremely important skill (why? Never used? Rarely practiced? Not of interest to most people)

Linton: Memory for autobiographical events Complex skills

• CPR is an important skill that is easily forgotten, what about less important skills? • Flying an airplane is a skill that is forgotten very slowly even if never practiced after originally learned • If a warm-up trial is given prior to test, virtually no forgetting occurs • Not true of all motor skills (some diminish quickly if not practiced) • Is it true that you never forget how to ride a bicycle?

Memory for meaningful episodic What does this tell us? material • Marigold Linton…diary method. • We know very little about forgetting • Write down the events of your day at day’s end • Rate of forgetting: only about 6% a year • Ebbinghaus’ studies are not as useful as • Does this mean she has a better memory than most? they once appeared and that forgetting • Meaningfulness of information and selection of incidents curve is misleading if taken too literally probably helped memory relative to Ebbinghaus’ over- exposure to nonsense syllables • Has this stopped psychologists from • More similar to how we probably remember real world theorizing (re: blindly guessing) about the events (occasionally recalling them and telling stories to people) causes of forgetting? Why do we forget? Consolidation theory • Not quite a theory of forgetting, based on the idea that forgotten information wasn’t stored • Three main explanations well initially (how can you forget something – problems that wasn’t in memory to begin with?) – Decay of information/interference of other • is not complete at the time that information (why?) practice or rehearsal ends – Retrieval failures (our springboard to talking • Perseveration (Muller & Pilzecker, 1900) – the about retrieval) consolidation of information to memory

Consolidation theory Consolidation theory • If perseveration is interrupted in any way the trace will not be consolidated and recall will not • Many different versions of consolidation theory, be possible all rest on the same three predictions • The longer the perseveratory period, the • Three key predictions made by consolidation stronger or more consolidated the memory trace theory: – Mental inactivity is more conducive to perseveration • Initial view: perseveration is STM, consolidated trace is LTM – Consolidation does not occur if the perseveration period is interrupted – Without consolidation, an item should never be recalled • More perseveration should lead to better recall

Support for consolidation Jenkins & Dallenbach (1924)

• Ebbinghaus: The first to note that he remembered • if perseveration is critical to LTM, then going more nonsense syllables when he slept between to sleep immediately after learning should help study and test…led to numerous related studies memory • Jenkins & Dallenbach (1924) • learn a short list of Ebbinghaus-type nonsense • Yaroush, Sullivan, & Ekstrand (1971) syllables (e.g., TUV, BIJ, etc) • Minami & Dallenbach (1946) • sleep or stay awake for 1 - 8 hours prior to test • Retrograde • Yaroush, Sullivan, & Ekstrand (1971) • Minami & Dallenbach (1946) Yaroush, Sullivan, & Ekstrand Sleep (1971) 0.9 0.8 0.7 asleep • Memory is even better if we prevent 0.6 subjects from dreaming while they sleep 0.5 0.4 0.3 • Note: while sleeping between study helps 0.2 awake learning, learning while you sleep

Proportion Correct 0.1 0 DOESN’T WORK 12345678 Hours Between Study & Test One interpretation: Sleep facilitates perseveration

Another piece of evidence for Minami & Dallenbach consolidation theory:

• Cockroaches as subjects • A loss of memory for events that occur • A response is conditioned in cockroaches before some sort of trauma/injury (avoiding a dark compartment of a box) • Even though memory is usually • Cockroaches then free to move around or lie recovered/restored over time, memory for inert (tissue paper lined cone) the events that happen immediately before • Conditioned response lasts longer in inert the injury are never remembered cockroaches • Trauma interrupts perseveration?

The problems The problems

• Despite some support for the first notion • Most of this earlier occurred with animal (inactivity better than activity), the other two ideas subjects…humans have more complex thought are difficult to test experimentally structures • In the early days of consolidation work, “retrieval” • What really goes on during perseveration? It’s was not an accepted concept so it was easy to say difficult to know if a perseveration period has that something that was forgotten wasn’t been interrupted or if it’s occurring because we consolidated (circular) don’t know what defines “mental inactivity” • We didn’t know then what we know now (i.e., • If we make someone wait in a room for 10 , it’s forgotten but not gone) minutes before recalling something, what are they • Too rigid an idea doing? Consolidation theory Interference theory

• Despite problems, may be partially correct • Rather than arguing that information doesn’t enter memory (consolidation), this is the notion that • We don’t know enough about physiological other information interferes processes and their cognitive consequences • Previous popular idea: information decays over to determine this time – E.g., memory isn’t as good if sleep occurs in • McGeoch (1932) the afternoon – It can’t just be decay! – Iron rusts over time, but time is not the causal agent – Circadian rhythms (aging differences reduced (oxidation is, this unfolds over time) when older adults run at “peak” times)? – forgotten over time, what is the causal agent? • Retroactive vs. proactive interference

Interference Interference theory Retroactive • Retroactive interference: information you learn after the original learning episode Exp’tal Learn A Learn B Recall A interferes with the previously learned Control Learn A --- Recall A material • Proactive interference: information you’ve Proactive learned prior to a learning episode disrupts Exp’tal Learn B Learn A Recall A your ability to remember that information Control --- Learn A Recall A

Evidence for interference theory Proactive interference

• Everything we just went over for • Retroactive interference is intuitive, forgetting out of need…what about proactive interference? consolidation theory: rather than • Discovered by Underwood in a literature review consolidating, mental inactivity means less (the more lists a subject learns prior to a final list, of a likelihood of retroactive interference the worse their memory is for that final list) • Underwood noted that when he redid the Ebbinghaus study, he forgot far less (20%) than Ebbinghaus (60%) over time

• Real world examples of PI: wrong name, mom Proactive Interference McGeoch’s 3 mechanisms Underwood (1948, 1957, 1964) of interference 1 0.9 . • McGeoch thinks that inability to recall something is 0.8 due to subjects recalling unwanted memories 0.7 . 0.6 (interference)…information is never actually lost 0.5 • Three mechanisms that can cause forgetting 0.4 .. – Response competition: two or more potential responses to a 0.3 . . . memory query (e.g. List A: cat-dog List B: cat-mouse) 0.2 . – Altered context: context dependent memory – memory worse

Proportion Correct Proportion 0.1 when tested in a different context (no retrieval cues) 0 – Set: A special version of context effects (where do I know 1 3 5 10 25 50 that person from) # of Prior Lists

Famous example of a “set” effect Problems for interference theory

• Part-list cuing • Difficult to account for PI and no posited • Originally explained in terms of inhibition mechanism to account for it (why hold onto • Actual cause: strategy disruption…your the name of an old partner or your old mental set has been violated telephone number)…RI is intuitive, forgetting out of need • McGeoch was influential enough though that the notion of decay is gone now

Retrieval failure Decay vs. Interference

• One nice thing about PI…killed decay outright • One of the most accepted theories nowadays though the idea of retrieval in general was not widely utilized until the • Brown-Peterson paradigm 1960’s. • Big advantage – doesn’t rely on only a single mechanism • Why: names at a party, irregular parking spot (old of forgetting (e.g. decay vs. interference, can be multiple habits wreck new learning) things) • Retrieval failure example: trying to remember something • A new idea: functional decay theory (Altman & today that you can’t, comes back to you tomorrow Gray, 2002)…information decaying out of • Another example: rushing to the internet, remembering on necessity when new information overwrites it the way • Forgetting here is temporary, happens all the time (if you knew where to look, you’d remember) Recall vs. Recognition Quick intro to retrieval (more to come) • Arguably the most convincing evidence • Capital of Rhode Island? for retrieval failure? • How long would it take us to figure something out if we had to search through every item we have in memory (Tulving) • Tomkins (1970): 400 years; Norman (1968): N/2; • We can be influenced Landauer (1986): 109 by information we • If you know 10 billion things and you can search an item can’t consciously every tenth of a second, how long would it take you to find something (about 16000 years) recall • LTM is “content addressable” – we know where to look • Retrieval was not a viable • …and now back to forgetting construct until Tulving made the explicit/implicit distinction

Explicit/implicit More Tulving Goodness

• Can explicitly remember about 40% of • With successive retrievals of a list of words, material in a list learning study but subjects often recall the same number of estimates for implicit memory are upwards words, but not the same words (available of 90% but not accessible, much like recognition • Lots of information is available to us that tasks…but is this merely evidence of a we are not conscious of drawback of experimental research???) • Otherwise, no difference between recall and recognition • Do people in really recall everything they can?

Other evidence in support of Other evidence in support of retrieval failure retrieval failure • The effect of retrieval cues • State dependency – memory is improved when – Imagine you hear something in lecture and you think retrieval occurs in the same state as (e.g., about it in the context of something you heard in another lecture (multiple retrieval paths to the same internal context) memory makes recall more likely) • Encoding specificity – similar to state – E.g. Does the current situation in Iraq remind you of anything you learned in class recently…memory dependency…match between contexts at test and connection to me here is useless retrieval are key (when writing the final exam, • State dependency imagine original context…e.g., external context) • Encoding specificity • phenomenon • Tip of the tongue phenomenon Other evidence in support of Retrieval failure retrieval failure • Tip of the tongue phenomenon • The most accepted of the aforementioned • - "It is a gap that is theories intensely active. A sort of wraith of the • Like most competing theories, it’s probably name is in it, beckoning us in a given the case that the real explanation for forgetting is a combination of the theories direction, making us at moments tingle with I’ve just outlined the sense of our closeness and then letting • Create your own “unified” theory of us sink back without the longed-for term." forgetting, get rich and famous

Suggested additional reading

• Schacter, D.L. (1999). : Insights from psychology and cognitive neuroscience. American Psychologist, 54, 182-203 • ….or if you’re really keen Schacter, D.L. (2001). The seven sins of memory: How the forgets and remembers. Boston: Houghton Mifflin.