120 February 2014Chapter 7- MemoryMemory is the capacity of the nervous system to acquire and retain usable skills and knowledge, allowing living organisms to benefit from experience. Basic Stages● Encoding - processing info so that it can be stored● Storage - retention of encoded representations over time that corresponds to some change in the nervous system that registers the event● Retrieval - recovering info from memory stores when it is neededMemory ModelStimulus -> Sensory Memory -> Attention ->Short Term Memory -> Encoding -> Long Term MemoryIf don’t process info in Sensory memory, STM, or LTM will forgetRetrieval is from LTM to STM● Stimulus - something from the environment● Sensory Memory - memory system that very briefly stores sensory information in close to its original sensory form, all information perceived is going through sensory memory○ separate sensory-memory store for each sensory system, persists for ⅓ of a second then progressively faces ■ visual - iconic memory● Testing for Iconic Memory (Sperling)○ fixation○ letter array shown briefly○ a tone/signal which row to report - remember letters better■ Auditory - echoic memory● Attention - Information that has been attended to is passed from sensory stores to short term memory● Short Term Memory - memory storage system that briefly holds a limited amount of information in awareness, give us information that we need to work with right now○ function - active processing of info for current use○ capacity - 7+/-2 [memory/digit span]○ Duration - ~20 seconds○ Flow of conscious thought - amount of information that flows through is large○ To keep in memory, have to do rehearsal, or else going to forget○ Chunking - process of grouping distinct bits of information into large wholes to2increase short term memory capacity○ Serial Position Effect■ indicates the tendency to recall more items from the beginning and end ofa list than from the middle, U shaped graph■ Primacy and Recency - both groups of subjects showed primacy effects, good recall of first items on the list Only the no-delay group showed recency effects, good recall for the last items ■ add distractions so persons cannot rehearse, memory lost● Encoding - ● Long Term Memory ○ Semantic Network - complex web of semantic associations that link items in memory such that retrieving one item triggers the retrieval of others as well■ associating things together are going to be stored closer together in network “doctor” associated with apple, patient, medicine etc○ Explicit Memory - Stored long-term knowledge of facts about ourselves and the world, declarative, conscious■ Semantic Memory - facts/general knowledge, not usually personal (knowing presidents of US)■ Episodic Memory - specific events (knowing that you completed an exam)○ Implicit Memory - nondeclarative, unconscious, stored long-term knowledge of learned habits and skills■ Procedural - learned habits and skills, how to ride a bikePriming - exposure to a stimulus influences a response to a later stimulus,is implicit because you don’t need to consciously recall seeing the primingstimulus in order for priming to occur● Conceptual priming - when priming stimulus influences flow of thought and activates concepts that are stored in semantic memory● Perceptual Priming - when a priming stimulus enhances ability to identify a test stimulus based on its physical features, priming withactual physical featureTests for Implicit and Explicit Memory● Amnesic Patients and normal controls were tested for memory of words learned previously● Amnesics performed poorly on explicit memory tasks, performance on implicit memory tasks was similar to control subjects● Explicit test - recall information stored RECALL & RECOGNITION3● Implicit test - word-fragment completion, word-stem completion● Amnesia ○ Anterograde amnesia - inability to store new information○ Retrograde amnesia - inability to retrieve memories from the pastPatient HM● severe seizures, so removed medial temporal lobe bilaterally, including hippocampus● performed when he was 27 years old● surgery was success, seizures improved● two years later, he still said he was 27 years old● unable to form or store any new memories● Short term memory was in tact● long term memory - anterograde amnesia (couldn’t form new memories)● Procedural memory - in tact● Declarative memory - none for after the surgery● Implicit memory - did learn some new tasks, no explicit memory of tasks425 February 2014Memory DistortionMisInformation effect - tendency for post-event misinformation to become integrated into memory of an event, aren’t always able to distinguish between real information from the event vs post event information● Elizabeth Loftus○ Loftus 1974: participants view film of car accident■ Key question: about how fast were cars going when they ---- each other?-choose for different group of participants: bumped, collided, contacted, hit, smashed ● Words have the ability to create post-event images, depending on which verb was used = different speed estimates (contact: 30.8, hit 34.0, bumped 38.1, collided 39.3, smashed 40.8)○ Loftus 1975: participants view film of automobile accident● Critical question: article change: ○ 1. Did you see a broken headlight? ○ 2. Did you see the broken headlight?● The latter question reliably produces false memory for a broken headlightEyewitness Identification - ● Gary Wells - eyewitness identification researcher○ initiated changes in eyewitness identification for crimes, different way of line up ( not showing them all at once, but one at a time: sequential so cannot make comparisons between photos ), don’t have a person who knows the real criminal conducting the lineup - can put off unconscious hints● The Innocence Project○ created in 1992 by Scheck and Neufeld, non-profit clinic○ post conviction DNA testing yields proof of innocence; clients mostly poor and forgotten○ freed over 300 prisoners who were wrongly convicted, ⅔ convicted because of mistaken eyewitness identification■ Ron Cotton rape case - still need eyewitnesses for trials, but people are more informed and know what can happen● Eyewitness Testimony○ How accurate are eyewitness accounts?○ Three conclusions about eyewitness testimony■ eyewitnesses are imperfect5■ certain personal and situational factors