Chapter 7: Exploring Human Memory

Chapter 7: Memory

• Memory is an active system that receives, stores, organizes, alters, and retrieves information.

Memory Processes

• Encoding is converting information into a form that can be retained in memory, like typing information into a document.
• Storage is keeping encoded information for later use, similar to saving a document.
• Retrieval is taking a memory out of storage and remembering it, like re-opening a saved document.

Atkinson-Shiffrin Model of Memory

• Incoming information is first processed in sensory memory.
• Selective attention filters sensory input into short-term memory.
• Rehearsal helps maintain information in short-term memory.
• Successful coding leads to storage in long-term memory.
• Information not attended to or coded can be forgotten.

Types of Storage: Sensory Memory

• Sensory memory holds snapshots of experiences, including sights, sounds, and smells.
• An icon is a fleeting mental image or visual representation.
• An echo is a brief continuation of sound in the auditory system.
• Sensory memory has a large capacity but a short duration.
• Visual images last for about 1/10 of a second, while sounds last for about 2 seconds.

Types of Storage: Short-Term Memory (STM)

• STM has a small capacity and duration.
• Selective attention is needed to transfer information from sensory memory to STM.
• Without more encoding, short-term memories aren't stored for long.

Working Memory

• Working memory allows you to keep things in mind while working and is exemplified by remembering an address long enough to type into Maps, adding two numbers in the head, and following a conversation.
• Maintenance rehearsal keeps information in working memory, for example, repeating an address out loud while searching for a phone.
• Interference, such as an interruption, can kick things out of working memory.
• The capacity of STM is about 7 ± 2 bits of information.
• Most people can hold about 7 bits (meaningful units) in working memory.
• Digit span tasks test working memory and are often part of IQ testing.
• Chunking allows more information to be stored in STM.

STM vs. LTM

• Short-term memory (STM) and long-term memory (LTM) are distinct.

Types of Storage: Long-Term Memory (LTM)

• LTM has a huge (possibly unlimited) capacity and a long duration.
• Consolidation involves physiological changes in the hippocampus to store information.
• Elaborative rehearsal links new information to existing memories and knowledge, helping transfer information from STM to LTM.
• Procedural memory involves learned skills or conditioned responses; like knowing how to tie shoes or checking a phone when hearing a vibration.
• Declarative memory involves facts.
• Semantic memory is for impersonal, everyday facts and knowledge, like "Tigers are cats" or "there are 206 bones in the human body."
• Episodic memory is for personal events linked with autobiographical details, such as I saw a tiger at the zoo when I was 5.

Storage and Retrieval Imperfections

• Pseudo-memories are false but believed to be true.
• Witness testimony can be inaccurate.
• Constructive processing can update a memory after it's stored, aligning memories with new information and filling in gaps.
• Tip-of-the-tongue (TOT) occurs when you know you know it but can't retrieve it.

Redintegrative Memory

• One memory serves as a cue for another, revealing previously inaccessible memories.

Recall vs. Recognition

• Recall is directly retrieving information. Example, knowing who won the Superbowl.
• Recognition is correctly identifying previously learned information.
• Recognition can be affected by distractors.
• False positives can happen when a wrong answer feels correct.
• A serial position effect is when the first and last items in a list being memorized are easiest to recall.
• The primacy effect involves remembering the first item.
• The recency effect involves remembering the last item(s).
• Primacy and Recency effects are both due to information still in STM.

Relearning

• Relearning is faster than initial learning.
• Savings score refers to how much faster you learn something the second time, often around 25%.

Explicit vs. Implicit Memories

• Explicit memories can be consciously recalled and told to someone else, like facts and past events.
• Implicit memories are difficult to articulate but are still known, like what letters are next to V on the keyboard.

HM and Implicit/Explicit Memory

• Henry Molaison (born 1926) underwent brain surgery to control seizures, resulting in anterograde amnesia.
• Anterograde amnesia is the complete inability to form new explicit memories after the surgery
• He could still learn new skills, even without remembering ever trying them before.

Forgetting

• To remember, a memory must be encoded, available, and accessible.

Ebbinghaus Forgetting Curve

• Immediate recall is best, with a sharp decline.
• Recall eventually stabilizes at a plateau.
• The trend is similar for meaningful information, but slower.

Encoding Failure

• Study is important because merely listening may not be enough to encode a useful memory.

Storage Failure: Memory Decay

• Sensory memory and STM both decay very rapidly.
• LTM also decays, sometimes from disuse. Memories that are never or rarely retrieved may become impossible to recall.
• Retrieved memories can still be retrieved, which indicates they didn't decay in the same way as STM.

Retrieval Failure

• Involves knowing something, yet being unable to bring it to mind.
• Example, knowing someone from class at a party but being unable to recall their name.

Memory Cues

• Can help you to retrieve memories.

State-Dependent Learning

• Remembering a list of words is easier when your mood matches learning.

Information Interference

• New memories might interfere with retrieving older material.
• Sleeping right after learning something new generally leads to better memory retention than staying awake.
• Retroactive interference occurs when new learning interferes with old memory.

Repression & Suppression

• Repression is motivated forgetting, usually of unpleasant stuff.
• Suppression is the deliberate act of not thinking about something that is unpleasant and is different from repression because you can still recall it it if prompted.

Flashbulb Memory

• Memories created during emotionally significant events are often associated with tragedies.
• Flashbulb memories, which feel extremely vivid, are not always accurate.

Eidetic Imagery

• Involves retaining the details of an image without continuing to look at it for at least 30 seconds.
• The image is projected onto a blank surface and is more common in childhood and rare in adults.

Memory Structures

• Memory structures make up who we are! and the whole brain is involved.
• The hippocampus consolidates memory from STM to LTM and HM and Clive Wearing both had hippocampus damage.

Ways to Improve Memory

• Knowledge of Results: Feedback to check progress.
• Recitation: Summarizing aloud while rehearsing.
• Rehearsal: Reviewing information mentally (silently).
• Selection: Selecting most important concepts to memorize.
• Organization: Organizing difficult items into chunks

Ways to Improve Memory

• Part Learning: Studying subparts of a larger body of information.
• Progressive Part Learning: Breaking learning task into a series of short sections.
• Serial Position Effect: Making most errors while remembering the middle of the list.
• Overlearning: Studying further once bare mastery is achieved.
• Spaced Practice: Alternating study sessions with brief rest periods.
• Massed Practice: Studying for long periods without rest periods.

Ways to Forget

• Hunger and lack of sleep decreases retention
• Eating well and and taking naps are conducive to studing.

Mnemonic Devices

• Memory tricks include singing or remembering a phrase to remind you of something more difficult.
• Creating mental images.
• Making things meaningful and familiar
• "My Very Easy Method Just Speeds Up Naming Planets" is a mnemonic device.