Learning and Memory

Question 1

Habituation

Answer 1

• Habituation: Decrease in response caused by repeated exposure to same stimulus. Student’s reaction to seeing cadaver lessens every time he see one (anxious at first, but unfazed afterwards).
• Subthreshold Stimulus: Stimulus too weak to elicit response.
• Dishabituation: Recovery of response to stimulus after habituation has occurred (when second stimulus is present). You get used to sights, sounds, sensations of driving on interstate during a trip, but you pay more attention when you use an exit ramp.

Question 2

Associative Learning

Answer 2

• Associative Learning: Creation of pairing or association between two stimuli (Classical Conditioning) or between behavior and response (Operant Conditioning).

• Classical Conditioning: Neutral stimulus is turned into a conditioned stimulus by pairing neutral stimulus to unconditioned stimulus to elicit a conditioned response. In Pavlov’s experiment, meat (unconditioned stimulus) caused dogs to reflexively salivate (unconditioned response); he repeatedly rang a bell (neutral stimulus) before giving the meat to the dogs, and over time, the sound of the bell (conditioned stimulus) caused dogs to reflexively salivate (conditioned response).
• Acquisition: Process of using unconditioned stimulus to turn neutral stimulus into conditioned stimulus to elicit reflexive response.
• Extinction: Loss of conditioned response that occurs if conditioned stimulus is repeatedly presented without unconditioned stimulus. If bell is rung too many times without dog getting meat.
• Spontaneous Recovery: Presenting subject with extinct conditioned stimulus produces weak conditioned response.
• Generalization: Broadening effect by which stimulus similar enough to conditioned stimulus also produces conditioned response. Little Albert conditioned to be scared of white rat, but became scared of white rabbit as well.
• Discrimination: Subject learns to distinguish between similar stimuli.
• Operant Conditioning: Examines ways in which consequences of volunteer behaviors (reinforcement or punishment) changes the frequency of those behaviors.
• Reinforcement: Process of increasing the likelihood of performing a behavior. Positive reinforcers increase frequency of behavior by adding a positive consequence or incentive following the desired behavior (earning money incentivizes employees to work). Negative reinforcers increase the frequency of a behavior but by removing something unpleasant (taking aspirin reduces headache).
• Punishment: Process of decreasing occurrence of behavior. Positive punishment adds unpleasant consequence to reduce behavior (flogging criminals to stop them from committing crimes again). Negative punishment removes positive stimulus to cause reduction of behavior (forbidding child from watching TV for bad behavior).
• Reinforcement Schedules: Fixed-Ratio Schedule (reinforces behavior after specific number of performances of that behavior; rat rewarded food pellet every third press of lever), Variable-Ratio Schedule (reinforces behavior after varian number of performances of that behavior; rat rewarded after two presses, then six, then five), Fixed-Interval Schedule (reinforces first instance of behavior after specified time period has elapsed; once rewarded pellet, rat must wait 60 seconds and press lever to receive another pellet), Variable-Interval Schedule (Reinforces behavior the first time it is performed after varying interval of time; rat rewarded upon lever press after 30 seconds, then upon lever press after 60 seconds, then upon lever press after 20 seconds).
• Variable-Ratio is fastest schedule for learning new behavior, has fastest response rate, and very resistant to extinction. Fixed schedules often have brief moment of no response after behavior is reinforced (rat will stop pressing lever until it wants another pellet, once it has figured out what behavior is necessary to receive another pellet).
• Shaping: Process of rewarding increasingly specific behaviors that become closer to desired response. Bird being trained to turn around and peck keyboard, so it is rewarded for turning slightly to the left, then for turning around completely, then finally for turning and pecking.
• Latent Learning: Learning that occurs without a reward but that is spontaneously demonstrated once a reward is introduced.
• Problem Solving: Ability to observe and analyze a situation and take decisive action to solve a challenge.
• Preparedness: Biological predisposition to learn behaviors based on an animal’s own natural abilities and instincts.
• Instinctive Drift: Reversion to instinctive behavior after learning new behavior that is similar.

Question 3

Observational Learning

Answer 3

• Observational Learning: Process of learning new behavior or gaining information by watching others. Bandura’s Bobo doll experiment in which kids watched an adult punch and kick a Bobo doll and then proceeded to inflict similar violence on doll when allowed to play in the toy room. In later iterations of the Bobo doll experiment, children who watched the adult get scolded after attacking the Bobo doll were less likely to be aggressive toward the Bobo doll themselves.
• Mirror Neurons: Neurons located in frontal and parietal lobes of cerebral cortex that fire both when individual performs an action and when that individual observes someone else performing same action and that allow for imitative motor and emotional (empathetic) learning.
• Modeling: Learning what behaviors are acceptable by watching others perform them.

Question 4

Memory (Encoding)

Answer 4

• Formation of Memories can be divided into three major processes: Encoding, Storage, Retrieval.

• Encoding: Process of putting new information into memory.
• Automatic Processing: Information gained without any effort, unintentionally.
• Controlled Processing: Information gained through effortful work, intentionally. Controlled Processing can become Automatic Processing with practice. When controlled processing is required, meaning of information can be encoded via visual encoding (by visualizing it), acoustic encoding (by the way it sounds), elaborative encoding (by linking it to knowledge already in memory), or semantic encoding (by putting it into meaningful context). Semantic encoding is strongest, especially if done using self-reference effect (information is put into context of one’s own life). Visual encoding is weakest. Other encoding aids are Maintenance Rehearsal (repetition of piece of information to either keep it in working memory to prevent forgetting or to store it in short-term and eventually long-term memory), Mnemonics (Method of Loci and Peg-Word), and Chunking (grouping individual elements of list together into groups of elements with related meaning).

Question 5

Memory (Storage)

Answer 5

• Formation of Memories can be divided into three major processes: Encoding, Storage, Retrieval.

• Sensory Memory: Preserves information in its original sensory form with high accuracy but for only a very short time (less than a second). Consists of both iconic memory (fast-decaying memory of visual stimuli) and echoic memory (fast-decaying memory of auditory stimuli). Sensory memory fades very quickly, unless attended to. When asked to list all letters presented in three-by-three array, participant could only correctly identify three or four letters (whole-report). When asked to list letters of particular row immediately after presentation, participant can identify letters with 100% accuracy (partial-report).
• Short-Term Memory: Retention of information (about 7±2 items, according to individual’s memory capacity) for about 30 seconds without rehearsal in hippocampus, where consolidation of short-term memory into long-term memory occurs.
• Working Memory: Keeps a few pieces of information in consciousness simultaneously and allows for it to be manipulated by integrating short-term memory, attention, and executive function. Involves hippocampus, as well as frontal and parietal lobes.
• Long-Term Memory: With enough rehearsal, information moves from short-term memory to long-term memory, which is an essentially limitless warehouse for knowledge that can be recalled on demand for a long time. Consolidation into long-term memory can occur via elaborative rehearsal (association of information to knowledge already stored in long-term memory, similar to self-reference effect). Long-term memory controlled primarily by hippocampus, but eventually moved to cerebral cortex, such that very long-term memory (name, birthday, parents’ faces) won’t be affected by damage to hippocampus.
• Two types of long-term memory: Implicit Memory consists of skills, habits, conditioned responses (that do not need to be consciously recalled) and includes procedural memory (skills required to complete procedural tasks) and priming (positive priming occurs when exposure to first stimulus improves processing of the second stimulus, such as decreased response time or decreased error rate; negative priming occurs when exposure to first stimulus interferes with processing of the second stimulus, resulting in slower response times and more errors). Explicit Memory consists of episodic memory (recollection of life experiences) and semantic memory (recollection of ideas, concepts, facts not tied to specific life experiences); autobiographical memory is explicit memory about one’s own life (episodic) and personal traits/characteristics (semantic), and flashbulb memory is explicit memory about stimuli immediately surrounding important or emotionally arousing event (do you remember when you were…?).

Question 6

Memory (Retrieval)

Answer 6

• Formation of Memories can be divided into three major processes: Encoding, Storage, Retrieval.

• Retrieval: Process of demonstrating that something that has been learned has been retained. Recall is retrieval or statement of previously learned information, but learning can be additionally demonstrated by recognizing or quickly relearning information.
• Recognition: Process of merely identifying a piece of information that was previously learned, easier than recall. MCAT largely based on recognition.
• Relearning: Stored information that is not readily available for recall; retention of information is most effective when sessions of relearning are spaced out over an extended period of time (spacing effect).
• Semantic Network: Stored information is organized such that concepts are linked together based on similar meaning, much like Wikipedia where each page includes links for similar topics. Spreading Activation refers to unconscious activation of linked concepts when one node of semantic network is activated; related to positive priming, as recall is aided by first being presented with word/phrase (recall cue) that is close to the desired semantic memory.
• Context Effect: Retrieval cue where memory is aided by being in a physical location where encoding took place (facts learned underwater are recalled better underwater). Source monitoring involves determining origin of memories, whether they are factual (from real life) or fictional (from dream, movie).
• State-Dependent Effect: Retrieval cue where memory is aided by being in same mental state as when information was learned (skills learned while intoxicated are recalled better when intoxicated) and recall of negative or positive memories will lead to persistence of mood.
• Serial-Position Effect: Position of items in memorized list affect their recall. Primacy Effect refers to tendency for high recall of first few items in list, and Recency Effect refers to tendency for high recall of last few items in list. Over time, primacy effect remains strong and recency effect fades.

Question 7

Forgetting and Brain Disorders

Answer 7

• Amnesia: Significant loss of long-term memory. Source Memory is inability to remember where, when, how knowledge was obtained.
• Alzheimer’s Disease: Degenerative brain disorder linked to loss of acetylcholine in hippocampus, marked by progressive dementia (loss of cognitive function), retrograde amnesia (loss of memories made before onset), brain atrophy, neurofibrillary tangles and beta-amyloid plaques, and sundowning (increase in dysfunction in the late afternoon and evening).
• Korsakoff’s Syndrome: Memory loss caused by thiamine deficiency in brain, marked by both anterograde amnesia (inability to form new memories), retrograde amnesia (loss of previously formed memories), confabulation (process of creating vivid but fabricated memories).
• Agnosia: Loss of ability to recognize objects, people, or sounds, occurs due to physical damage to brain (from stroke or multiple sclerosis).
• Decay: Natural loss of memories as demonstrated by Retention Curve.
• Interference: Retrieval error caused by existence of other, usually similar, information. Proactive interference is caused by old information interfering with new learning (new address hard to remember because of old address). Retroactive interference is caused by new learning interfering with old information (learning new names every semester makes remembering old names harder).
• Aging: Aging does not necessarily lead to significant memory loss. Prospective Memory (remembering to perform a task at some point in the future) is best when event-based (buying milk when driving past store), hardest when time-based (taking medication at 7PM).

Question 8

Memory Reconstruction

Answer 8

• Reproductive Memory: Accurate recall of past events, not a realistic view of memory.
• Reconstructive Memory: Memory recall theory in which act of remembering is affected by imagination, semantic memory, and perception. False memory describes a memory that incorrectly recalls actual events or recalls events that never occurred. Recovered memories are repressed memories that have been brought back into consciousness. Hard to distinguish between false memories and recovered memories.
• Misinformation Effect: Recall of an event becomes less accurate due to the injection of outside information into memory (car stopped at yield sign is remembered as being stopped at stop sign).
• Intrusion Errors: False memories that have included a false detail into a particular memory; similar to miss information effect but intrusion error is not from outside source, it is from the injection of a related memory into the original memory (subject has celebrated NYE and then eaten at restaurants in UK and US, but recalls celebrating NYE and then eating at a restaurant that he believes was in the US but that was actually in the UK).
• Source-Monitoring Error: Confusion between semantic and episodic memory; details of an event are remembered but the context under which those details were gained is confused (person hears a story of something that happened to someone else and later recalls the story as having happened to himself).

Question 9

Neurobiology of Learning and Memory

Answer 9

• Neuroplasticity: Rapid reorganization of neural connections in response to stimuli; really high neuroplasticity in children when compared to adults (the remaining hemisphere in the brain of a child who has had an entire hemisphere removed to prevent severe seizures can change to take over functions of the missing parts of the brain).
• Synaptic Pruning: Weak neural connections are broken while strong neural connections are bolstered to increase efficiency of brain’s ability to process information.
• Long-Term Potentiation: The strengthening of neural connections through repeated use; memory trace is formed during neural activity (basis of short-term memory), but repeated stimulation causes presynaptic neurons to become more efficient at releasing neurotransmitters and causes receptor density to increase on postsynaptic neurons (basis of long-term memory).