Long-Term Memory 2 (Chapter 7) PDF

Long-Term Memory 2 (Chapt. 7, continued) Forgetting & Retrieval (continued) Consolidation  Why Retrieval Failures? 1. Poor retrieval cues 2. Interference Consequences of Retrieval Cues A. Relative difficulty of memory tests B. Encoding specificity C. State dependent rec...

Long-Term Memory 2 (Chapt. 7, continued) Forgetting & Retrieval (continued) Consolidation  Why Retrieval Failures? 1. Poor retrieval cues 2. Interference Consequences of Retrieval Cues A. Relative difficulty of memory tests B. Encoding specificity C. State dependent recall D. Transfer appropriate recall  Why Retrieval Failures? 1. Poor retrieval cues 2. Interference  2. Interference Interference arises in LTM because retrieval cues activate multiple traces. – The intended memory trace will be activated but so too will traces that are similar. These multiple activations result response competition, which results in – Intrusions: Recall wrong information – Inability to recall anything! Example: Memorizing Similar Material George Washington was John Adams was the 2nd the 1st U.S. president, U.S. president, serving serving from 1789 to from 1797 to 1801. His 1797. His vice president vice president was was John Adams. He was Thomas Jefferson. He born in Virginia and and is was born in referred to as the “Father Massachusetts and is of the Nation” because of considered one of the his leadership during the “Founding Fathers.” He American Revolutionary was criticized by his rival, War… Alexander Hamilton… Thomas Jefferson was the James Madison was the 3rd U.S. president, serving 4th U.S. president, from 1801 to 1809. His serving from 1809 to first vice president was 1817. His first vice Aaron Burr. He was born president was George in Virginia and was the Clinton. He was born in principal author of the Virginia and is known as Declaration of the “Father of the Independence. During his Constitution.” He led the life he owned more than U.S. into the War of 1812 600 slaves… against Britain…  Example: Retrieving Similar Material Long-Term Memory Activated items compete during retrieval, sometimes resulting in nothing being retrieved. Working Memory Washington = 1st president, born in Virginia… Adams = 2nd president, born in Who is the Massuchesetts… 4th U.S. president? Wrong item sometimes retrieved, resulting in an intrusion (e.g., Madison = 4th president, born in retrieving information Jefferson = 3rd president, born in Virginia… about Adams instead Virginia… of Madison). Interference and Distinctiveness Interference is reduced to the extent that memory items are distinct. Examples – Deep processing will reduce interference if it makes studied items more distinct.  Summary of Retrieval Failure Forgetting is often a case of retrieval failure. – Use of ineffective retrieval cues. – Interference due to response competition. Retrieval failures often persist because we keep using the same retrieval cues. – It is usually best to try again later! Tip-of-the-tongue can often be eliminated by trying again later.  Topics in Chapter 7 Encoding Forgetting and Retrieval Consolidation  Consolidation A general principal about new memories is that they are often initially weak. – Unlike most people’s intuitions, memories actually tend to get stronger with time! Consolidation refers to the brain processes that strengthen memories over time! Synaptic vs. System Consolidation Synaptic consolidation takes places over minutes or hours and involves changes to the synapses. – Covered in book (pp. 208-210) System consolidation takes places over months or years and involves the reorganization of long-term memories. System Consolidation and RA Initial evidence for system consolidation came from retrograde amnesia (RA). In retrograde amnesia, memory loss is usually temporally graded. – Greatest loss of more recent PAST FUTURE memories, least loss of oldest memories.  Example of Temporal Gradient (Butters & Cermak, 1986) Patient PZ Earlier memories – Eminent university exhibit the least loss. scientist. – Onset of Korsakoff Most recent memories exhibit syndrome in 1985 the greatest loss. (age 65). Tested for information in his own autobiography.  Example of Consolidation (Muller & Pilzecker, 1900) The 6 min delay allowed List 1 material to be Ss study Delay of Results consolidated, List 1, 17 sec. resulting in better recall. consisting of Immediate 60% paired group Ss study associates. List 2 50% (different Example items than 40% Percent Accuracy PUK-DAX Delay LOC-PED group List 1). 30% YAT-CAJ Delay of 6 min. Cued 20% Recall 10% Test Example 0% Immediate Group Delay Group PUK-??? LOC-???  Consolidation and Sleep There is evidence that consolidation is especially frequent during sleep! – Thus, material acquired just before sleep may be retained especially well. In 2006, Gais et al. tested for a memory advantage if subjects went to sleep immediately after studying…  Consolidation and Sleep (Gais et al, 2006) Day 1 Day 2 Day 3 8PM Night 8AM Night 8AM Sleep group Ss study Sleep 24 pairs of Cued Cued German- Recall Recall English Sleep Test Test vocabulary Watch 1 2 words for TV, 10 min. play Sleep video Awake games, group etc.* (*Subjects were asked to not read, in order to reduce interference.)  Experimental Results Sleep group retained more (Gais et al., 2006) Caveat: The awake than the awake group. group may have also Suggests that memories experienced more are consolidated during interference (from sleep! new experiences)! 16.5 Recall Test 1 Recall Test 2 Number Recalled (out of 24) 16.0 15.5 15.0 14.5 14.0 13.5 13.0 Sleep group Awake group  Consolidation and Sleep Sleep not only enhances memories in general, it is selective. – Memories that we know are going to be tested later are more likely to be strengthened by consolidation (Wilhelm et al., 2011). The Theory of Reconsolidation When a memory is retrieved, its representation becomes unstable or fragile. For the representation to be retained, it needs be reconsolidated. – In the absence of reconsolidation, the memory is weakened or lost. Evidence for Reconsolidation (Nader et al., 2000a; 2000b) By preventing reconsolidation, Nader et al. was able to disrupt a memory in rats. – Used anisomycin, an antibiotic that disrupts the consolidation of memories. – Were able to eliminate the rats’ fear of a tone acquired via classical conditioning!  The Effect of Anisomycin Anisomycin prevents acquisition of a new association between stimuli (a memory)! Results of Disrupting Reconsolidation (Nader et al., 2000a; 2000b) When administered during activation of the memory, anisomycin interferes with its reconsolidation so that the memory is lost.  A Retrieval-Specific Effect (Nader et al., 2000a; 2000b) Anisomycin has no effect when the memory hasn’t been activated.  Purpose of Reconsolidation Reconsolidation may be important because it allows organisms to update old memories. – The retrieved representation’s fragility allows it to be updated with new information in case circumstances change. E.g., that the rat was not shocked on Day 2 may have led it to (quickly) update its expectations regarding tones.  Reconsolidation in Humans (Hupbach et al., 2007) In 2007, Hupback et al. tested whether reconsolidation occurs in humans. All subjects learned two lists of objects, one on Day 1, the other on Day 3. – In the reminder condition, subjects were reminded of List 1 before learning List 2. – In the no-reminder condition, subjects were not reminded of List 1.  Experimental Design (Hupbach et al., 2007) Day 1 Day 3 Day 5 Learn List 1 Experimenter 1 Learn List 2 Experimenter 1 reminds S of Experimenter 1 presents 20 Day 1 learning, places 20 new objects one by shows blue objects on table. one and places basket. Ss recall until them in blue learned. Free Free Recall basket. Recall List 1 List 1 Reminder Learn List 2 Group Experimenter 2 Ss are asked places 20 new to name and objects on table. attend to each Ss recall until object. No-Reminder Group learned. Repeat until 17/20 objects recalled. Experimental Results On Day 3, the Reminder group’s (Hupbach et al., 2007) representation of List 1 was unstable and so vulnerable to List 2 intrusions. This resulted in worse List 1 recall performance on Day 5.  Clinical Applications (Brunet et al., 2008) Reconsolidation-based treatments have shown promise in treating PTSD. – A patient is reminded of a traumatic experience. – A drug (propranolol) is administered. May block reconsolidation. – When reminded of the experience a week later, patients show lowered levels of fear. Summary: Studying for Exams Depth of processing – Attempt to create a deep, semantically-rich understanding of the material. Retrieval practice – Don’t just read the textbook over and over! Encoding-specificity principle – The questions on the exam will be meaning- based. Thus, your understanding of the material had better be also! Cued recall! Summary: Studying for Exams Beware of interference – Learning a great deal of similar information at the same time will tend to cause interference. Sleep! Spacing effect – Study in multiple sessions, not just one. Tip-of-the-tongue (TOT) – If you can’t remember the answer to a question (TOT), skip it and try again later!  Next Lecture Chapt. 8, continued – Constructive nature of memory – Misinformation effect