8.1 How Memory Functions

Encoding

• Encoding: the input of information into the memory system.

• Automatic processing: the encoding of details like time, space, frequency, and the meaning of words.

  • Automatic processing is usually done without any conscious awareness.

• Effortful processing: the encoding of content, material, and information

• Material is far better encoded when you make it meaningful.

• Semantic coding: the encoding of words and their meaning.

• Visual encoding: the encoding of images

• Acoustic encoding: the encoding of sounds, words in particular.

• Semantic encoding involves a deeper level of processing than the shallower visual or acoustic encoding.

• Psychologists Fergus Craik and Endel Tulving conducted a series of experiments to find out which of the three types of encoding would give the best memory of verbal information.

  • Craik and Tulving concluded that we process verbal information best through semantic encoding, especially if we apply what is called the self-reference effect.

  • Self-reference effect: the tendency for an individual to have better memory for information that relates to oneself in comparison to material that has less personal relevance

Storage

• Storage: the creation of a permanent record of information.

• In order for a memory to go into storage, it has to pass through three distinct stages: Sensory Memory, Short-Term Memory, and Long-Term Memory.

  • These stages were first proposed by Richard Atkinson and Richard Shiffrin. Their model of human memory, called Atkinson-Shiffrin (A-S), is based on the belief that we process memories in the same way that a computer processes information.

• Baddeley and Hitch proposed a model where short-term memory itself has different forms.

  • In this model, the type of short-term memory depends on the type of information received. They’re stored in three short-term systems: a visuospatial sketchpad, an episodic buffer, and a phonological loop.

    • A central executive part of memory controls the flow of information to and from the three short-term systems.

Sensory Memory

• In the Atkinson-Shiffrin model, stimuli from the environment are processed first in sensory memory

• Sensory memory: storage of brief sensory events, such as sights, sounds, and tastes.

• It’s very brief storage—up to a couple of seconds.

• Sensory information about sights, sounds, smells, and even textures, which we do not view as valuable information, we discard. If we view something as valuable, the information will move into our short-term memory system.

Short-Term Memory

• Short-term memory (STM): a temporary storage system that processes incoming sensory memory.

• Short-term memory takes information from sensory memory and sometimes connects that memory to something already in long-term memory.

• Short-term memory storage lasts about 20 seconds.

• Rehearsal: the conscious repetition of information to be remembered

• Memory consolidation: to move STM into long-term memory

Long-Term Memory

• Long-term memory (LTM): the continuous storage of information.

• The storage capacity of LTM has no limits.

• Not all long-term memories are strong memories.

• Some memories can only be recalled through prompts.

• Long-term memory is divided into two types: explicit and implicit.

  • Explicit memories: those we consciously try to remember and recall.

  • Implicit memories: memories that are not part of our consciousness. They’re memories formed from behaviors.

• Procedural memory: a type of implicit memory that stores information about how to do things.

  • It’s the memory for skilled action

• Declarative memory: the storage of facts and events we personally experienced.

  • It has two parts: semantic memory and episodic memory.

• Semantic memory: knowledge about words, concepts, and language-based knowledge and facts.

• Episodic memory: information about events we have personally experienced.

Retrieval

• Retrieval: the act of getting information out of memory storage and back into conscious awareness.

• Our ability to retrieve information from long-term memory is vital to our everyday functioning.

• There are three ways you can retrieve information out of your long-term memory storage system: recall, recognition, and relearning.

  • Recall: to access information without cues.

  • Recognition: to identify information that you have previously learned after encountering it again. It involves a process of comparison.

  • Relearning: learning information that you previously learned.

8.2 Parts of the Brain Involved With Memory

The Amygdala

• The main job of the amygdala is to regulate emotions.

• The amygdala plays a part in how memories are stored because storage is influenced by stress hormones.

• Because of its role in processing emotional information, the amygdala is also involved in memory consolidation.

• The amygdala seems to facilitate encoding memories at a deeper level when the event is emotionally arousing.

The Hippocampus

• The hippocampus is involved in memory, specifically normal recognition memory as well as spatial memory.

• Another job of the hippocampus is to project information to cortical regions that give memories meaning and connect them with other connected memories.

• It also plays a part in memory consolidation.

• Injury to this area leaves us unable to process new declarative memories.

The Cerebellum and Prefrontal Cortex

• The cerebellum is involved in creating implicit memories

• The prefrontal cortex is involved in processing and retaining information.

• The left inferior prefrontal cortex involves semantics and the right inferior prefrontal cortex is involves in retrieval.

Neurotransmitters

• There’s specific neurotransmitters involved with the process of memory, such as epinephrine, dopamine, serotonin, glutamate, and acetylcholine

• There continues to be discussion and debate among researchers as to which neurotransmitter plays which specific role

• Communication among neurons via neurotransmitters is critical for developing new memories.

• Repeated activity by neurons leads to increased neurotransmitters in the synapses and more efficient and more synaptic connections. This is how memory consolidation occurs.

• Arousal theory: strong emotions trigger the formation of strong memories, and weaker emotional experiences form weaker memories

  • This is evidenced by what is known as the flashbulb memory phenomenon.

    • Flashbulb memory: an exceptionally clear recollection of an important event.

8.3 Problems With Memory

Amnesia

• Amnesia: the loss of long-term memory that occurs as the result of disease, physical trauma, or psychological trauma.

  • There are two common types of amnesia: anterograde amnesia and retrograde amnesia.

• Anterograde amnesia: you can’t remember new information, although you can remember information and events that happened prior to your injury

  • Anterograde amnesia is commonly caused by brain trauma

  • The hippocampus is usually affected, which suggests that damage to the brain has resulted in the inability to consolidate memories.

  • Many people with this form of amnesia are unable to form new episodic or semantic memories, but are still able to form new procedural memories.

• Retrograde amnesia: loss of memory for events that occurred prior to the trauma.

  • People with retrograde amnesia cannot remember some or even all of their past.

  • They have difficulty remembering episodic memories.

Memory Construction and Reconstruction

• Construction: the formulation of new memories

• Reconstruction: the process of bringing up old memories

• As we retrieve our memories, we tend to alter and modify them.

• A memory pulled from long-term storage into short-term memory is flexible.

  • New events can be added and we can change what we think we remember about past events, resulting in inaccuracies and distortions.

Suggestibility

• Suggestibility: the effects of misinformation from external sources that leads to the creation of false memories.

• We’re vulnerable to the power of suggestion, simply based on something we see on the news. Or we can claim to remember something that in fact is only a suggestion someone made.

• It’s the suggestion that’s the cause of the false memory.

Eyewitness Misidentification

• Even though memory and the process of reconstruction can be fragile, police officers, prosecutors, and the courts often rely on eyewitness identification and testimony in the prosecution of criminals. However, faulty eyewitness identification and testimony can lead to wrongful convictions.

• Unintended cues and suggestions by police officers can lead witnesses to identify the wrong suspect.

• Suggestive police identification procedures, such as stacking lineups to make the defendant stand out, telling the witness which person to identify, and confirming witnesses choices can lead to misidentification

The Misinformation Effect

• Misinformation effect paradigm: after exposure to incorrect information, a person may misremember the original event.

• An eyewitness’s memory of an event is very flexible due to the misinformation effect.

Controversies Over Repressed and Recovered Memories

• False memory syndrome: recall of false autobiographical memories.

• On one side of the debate are those who have recovered memories of childhood abuse years after it occurred. These researchers argue that some children’s experiences have been so traumatizing and distressing that they must lock those memories away in order to lead some semblance of a normal life. They believe that repressed memories can be locked away for decades and later recalled intact through hypnosis and guided imagery techniques.

• On the other side, Loftus has challenged the idea that individuals can repress memories of traumatic events from childhood and then recover those memories years later through therapeutic techniques such as hypnosis, guided visualization, and age regression.

  • Loftus questions whether or not those memories are accurate, and she is skeptical of the questioning process used to access these memories, given that even the slightest suggestion from the therapist can lead to misinformation effects.

• Steps have been taken to decrease suggestibility of witnesses.

  • Modify how witnesses are questioned. When interviewers use neutral and less leading language, children more accurately recall what happened and who was involved.

  • Use a blind photo lineup. This way the person administering the lineup doesn’t know which photo belongs to the suspect, minimizing the possibility of giving leading cues.

Forgetting

• Forgetting: loss of information from long-term memory.

• Encoding failure: when memory loss happens before the actual memory process begins.

  • If we don’t encode the information, then it’s not in our long-term memory, so we will not be able to remember it.

• Psychologist Daniel Schacter offers seven ways our memories fail us called the seven sins of memory and categorizes them into three groups: forgetting, distortion, and intrusion

  • Forgetting

    • Transience: memories can fade over time.

      • Storage decay: unused information tends to fade with the passage of time.

    • Absentmindedness: lapses in memory caused by breaks in attention or our focus being somewhere else.

    • Blocking: inability to access stored information

  • Distortion

    • Misattribution: when you confuse the source of your information.

    • Suggestibility: false memories

    • Bias: memories distorted by current belief system

  • Intrusion

    • Persistence: inability to forget undesirable memories

Interference

• Interference: information stored in our memory, but is inaccessible.

  • There are two types: proactive interference and retroactive interference

    • Proactive interference: when old information hinders the recall of newly learned information.

    • Retroactive interference: when information learned more recently hinders the recall of older information.

8.4 Ways to Enhance Memory

Memory-Enhancing Strategies

• Memory-enhancing strategies: helps make sure information goes from short-term memory to long-term memory

  • Rehearsal: the conscious repetition of information to be remembered

  • Chunking: to organize information into manageable bits or chunks

  • Elaborative rehearsal: to think about the meaning of the new information and its relation to knowledge already stored in your memory.

  • Mnemonic devices: memory aids that help us organize information for encoding

    • They are especially useful when we want to recall larger bits of information such as steps, stages, phases, and parts of a system