- Remembering More
- Here is a summary of some of the data about memory and forgetting.
The memory curve shows the basic pattern of forgetting discovered by
Ebbinghaus. While that pattern always remains the same, other factors
(see below) will move the curve up or down (but the shape remains the
same).
- Meaning makes forgetting occur more slowly. Items like words and
sentences are easier to learn and harder to forget.
- Items such as nonsense syllables and trigrams (CCCs or Consonant Consonant Consonant) are harder to learn and easier to forget.
- Chunking is a
term often used in memory research.
- It refers to the process of gathering many smaller items together and making a single larger item out of those smaller ones.
- Probably the best example are words.
- The 26 letters of the alphabet can be chunked into some 300,000 or so English words.
- Words can be chunked into sentences.
- Some sentences are sayings like: "You can lead a horse to water, but you cannot make him drink." Those sayings are easily remembered.
- If I had only showed you the first three words, you probably would have remembered the whole saying.
- Musicians play music in chunks.
- Beginning musicians read and play every note, but advanced musicians read and play musical phrases.
- They have chunked the notes and recognize them as a familiar group.
- Practice improves memory, but how you practice also affects it.
- The same amounts of practice, but distributed in the one case and
massed in the other, lead to different outcomes.
- Distributed practice
is when practice is spread out over time.
- For example, you may study a total of 12 hours for the next test; you did so over 6 days.
- Massed
practice is when practice is done all at once.
- For example, you study 12 hours the night before the test (Sound familiar?).
- Distributed practice
is when practice is spread out over time.
- Many studies have confirmed that the first strategy is the better one. Peopld emember more longer when they distribute their practice.
- The same amounts of practice, but distributed in the one case and
massed in the other, lead to different outcomes.
- Overlearning is when practice is continued beyond the criterion of
one error-free trial.
- Actors overlearn their lines.
- They will rehearse far beyond the time necessary for the criterion above.
- In the military, drills constitute overlearning.
- In sports, athletes practice far beyond the time necessary to meet the above criterion.
- In all of the cases above, overlearning helps to negate the negative effects of stress on memory.
- Overlearned items can be recalled under higher levels of stress than can items that were not overlearned.
- Actors overlearn their lines.
- Items encoded under high physiological arousal are remembered more
and longer.
- For example, combat veterans report their most vivid
memories are correlated with their arousal at the time the memory was
encoded.
- In some cases, the memories are so vivid that they disturb sleep.
- In another example, some professional baseball players report that they remember every pitch thrown to them in a World Series game.
- High student arousal may also account for why some lecturers are more memorable than others.
- The converse, encoding under low arousal, shows an opposite pattern to the high arousal data.
- For example, listening to audio while sleeping leads to little memory of items in those tapes.
- For example, combat veterans report their most vivid
memories are correlated with their arousal at the time the memory was
encoded.
- We are much better at remembering pictures than we are at
remembering words and names.
- There are probably biological and evolutionary reasons for that.
- When people are asked to recognize a small set of photos that they saw the previous day from a larger set, they typically recognize around 97% correct.
- Finally, flashbulb memory is a term used to describe a vivid
memory that was strongly encoded by a brief exposure to a memory
item.
- Good examples from history include:
- the attack on Pearl Harbor,
- the assassination of John F. Kennedy,
- the explosion of the Challenger space shuttle, 9/11.,
- or the Sandy Hook Shooting.
- People who were exposed to those events typically recall them very strongly, as if the memories had been frozen in the light of a flashbulb.
- Flashbulb memories can also be personal and private. For example, subjects are most likely to recall their first sexual experience compared to their tenth.
- Good examples from history include:
- Meaning makes forgetting occur more slowly. Items like words and
sentences are easier to learn and harder to forget.
- Here is a summary of some of the data about memory and forgetting.
The memory curve shows the basic pattern of forgetting discovered by
Ebbinghaus. While that pattern always remains the same, other factors
(see below) will move the curve up or down (but the shape remains the
same).
- Brains
- Organizing Principles of the Brain
- Think of a balloon with bumps on it
- Notice the linear structure from back to front: medulla, pons, cerebellum, inferior colliculus, superior colliculus, thalamus, hypothalamus, cerebrum
- In the human brain, the order of the parts is the same, except that the brain has rotated to accommodate walking on two legs
- The Hindbrain
- Medulla
- Pons
- Reticular Formation
- Cerebellum
- The Colliculi
- Inferior colliculus: reflexive monitoring of sound
- Superior colliculus: reflexive monitoring of light
- The Cerebrum or Neocortex
- Lobes
- Frontal
- rear contains motor homunculus
- 3-D motor homunculus (shows how some parts of the body are under more precise control/larger = more control)
- Frontal
- Lobes
- Organizing Principles of the Brain
- The size of the body part corresponds with the amount of brain tissue devoted to control. So you can control your hands and fingers better that your feet and toes.
- Parietal
- front contain sensory homunculus (shows how some parts of the body are more sensitive to tactile stimulation/larger = more sensitivity)
- 3-D sensory homunculus
- Again, but now the size of the body part reflects the amount of brain tissue devoted to sensory understanding. So, your lips and fingers are more sensitive than you back or your feet.
- Temporal
- parts of this lobe deal with language
- Occipital
- parts of this lobe deal with vision
- Limbic (in some texts)
- parts deal with emotional behavior and memory
- Much of cortex is "silent" (meaning that no overt is seen when directly stimulating these parts of the cortex)
- Hemispheric Specialization
- Brain has right and left halves that are physically identical mirror images but functionally different
- But, you do not have two brains
- Left hemisphere: language and logical thought
- Right hemisphere: rhythm, spatial relations, intuitive thought
- Some have reversed functions and left-handers are more likely to exhibit that reversal
- hooked writing style is diagnostic
- Wada Test
- "Split-brain" research
- Participants had epilepsy so the research was really therapy
- Corpus callosums were cut
- After:
- All wrote only with their right hands,
- but drew only with their left hands
- blindfolded, all could name an object in their right hands, but could not name the same objects in their left hands.
- All could identify objects in their right visual fields, but could not identify objects in their left visual fields.
- Agenesis: those born without corpus callosum (rare: 1 in 4000 people). Does not usually impair cognitive function
- Characteristics
- Complexity
- The human nervous system is one of the most complex systems known.
- Integration
- The brain along with senses and hormones work together to allow people to live and work effectively
- Adaptibility
- Learning, if nothing else, is the main factor in allowing learners (humans and animals) to adapt to new or unusual situations
- Learning and the nervous system work together in still unknown ways
- Electrochemical action
- Most nervous systems are electrochemical systems
- Information inside of neurons is transmitted electrically
- Information between neurons is transmitted chemically
- Complexity
- Pathways (more below)
- Afferent: pathway for information entering the brain
- Efferent: pathway for information exciting the brain
- Multipolar or Interneurons: are highly communicative within the brain
- Google's AI''s neuron images
- Harvard and Google provide a picture of a very small section of the brain
- They note:
- it's a very small sample from the temporal cortex (maybe one millionth of whole brain)
- mirror image neurons exist
- there were thousands of synapses
- axon whorls (a new finding)
- the networking at this small level is nearly incredible
- Divisions
- Central Nervous System (CNS)
- brain and spinal cord (70% of entire nervous system)
- Peripheral Nervous System
- everything except the CNS
- Somatic Nervous System
- relays information to brain
- executes brain's commands
- AKA: voluntary nervous system
- Autonomic Nervous System
- regulates involuntary functions such as breathing and heart rate
- Contains two branches
- Sympathetic
- prepares the body for action
- "fight or flight" response
- Parasympathetic
- calms the body "rest and digest"
- Sympathetic
- Autonomic Demos
- This one is safe. Time yourself for how long you can hold your breath.
- Safe if you are not underwater, that is.
- At some point, your autonomic nervous system will make you breathe.
- Did you make it to 11 or 24 minutes, the world records?
- The first record is without breathing pure oxygen first, the second is with breathing oxygen first. Here is a WEB PAGE that tells about those records.
- March 27, 2021: 24 minutes, 37 seconds (Budimir Sobat with pure oxygen first)
- Men: 11 minutes, 35 seconds (Stephane Mifsud, 2009, no oxygen first)
- Women: 8 minutes, 23 seconds (Natalia Molchanova, 2011, no oxygen first)
- This next demo is impossible:
- On the count of three, make your heart stop beating :-)
- This one is safe. Time yourself for how long you can hold your breath.
- Central Nervous System (CNS)
- Neurons and Glia
- The Neuron
- Number: around 80 to100 billion neurons
- Types:
- afferents: the one-way "highway" coming ENTERING the CNS
- efferents: the one-way "highway" LEAVING the CNS
- multipolar or interneurons: neurons in the central nervous system
- Parts:
- cell body
- nucleus
- dendrites
- axon
- terminal buttons
- GRAPHIC of a neuron
- Nerve Conduction:
Within the Neuron
- Nerve conduction is electrical within the neuron
- Neurons at rest are polarized
- The nerve impulse or action potential is a series of depolariztion events
- When depolarization reaches the terminal buttons neurotransmitter is released into the synapse
- Nerve Conduction: Between Neurons
- Neurotransmitter is released into the synapase, the narrow space between neurons
- Two things can happen:
- The nerve signal continues (an EPSP)
- The neve signal stops (an IPSP)
- See Integration and Summations links below for more information
- All-or-None Law
- A neuron can only fire in one way
- It cannot give a graded signal
- My example is an old Dennis the Menace cartoon
- In the cartoon I'll describe Dennis's dad is carrying him home, and Dennis says: "Of course I heard you, you just did not seem mad enough yet."
- (If anyone finds that cartoon let me know! I spent two hours looking for it last night!)
- In the cartoon I'll describe Dennis's dad is carrying him home, and Dennis says: "Of course I heard you, you just did not seem mad enough yet."
- Obviously, Dennis's dad had been calling him: Dennis, Dennis, DENNIS!
- He was using a graded signal (raising his voice)
- Neurons cannot do that. They can only change their rate of firing.
- Let me substitute the letter "D" for "Dennis" and look at a neuron. (In other words, neurons cannot "raise their voice." Instead, they might fire faster in order to communicate urgency
- Here is the early signal D----------D----------D----------D----------D
- Here is a later signal D-----D-----D-----D-----D-----D-----D
- Here is the last signal D--D--D--D--D--D--D--D--D--D--D
- The faster I say Dennis is the equivalent of me raising my voice.
- But a neuron cannot do that.
- Instead, the neuron changes its rate of firing and, thus, changes the information it is relaying
- Note that because of the refractory period (see below) the neuron cannot fire without some delay between each action potential
- In other words a neuron cannot go: DDDDDDDDDDDDDDDDDDDDDDDDDDD (or fire constantly)
- All-or-None Law
- Refractory period
- In physiology, refractory means not responding
- After a neuron fires it cannot fire again for a short period of time, that is its refractory period
- There are two refractory periods in the neuron
- Absolute Refractory Period where no stimulus can make the neuron fire again
- Relative Refractory Period where, following the Absolute Refractory Period STRONGER than normal stimulation can make the neuron fire again, sooner than normal
- The diagram below is from physiologyweb
- My metaphor is the "magic toilet"
- imagine a toilet that always gives you a full flush even when its tank is not full
- a real toilet cannot do that even if you hit the handle harder
- a magic toilet will flush fully at some point in its filling if you hit the handle harder. A real toilet will not
- but, a "half full" neuron will fire fully when more strongly stimulated during the relative refractory period (that's the "magic" part)
- See the Integration: All or none and summation link below for more details (FYI, that's were the cowpokes are.)
- There are two refractory periods in the neuron
- Myelination
- Axons in the peripheral nervous system are covered in myelin
- Myelin is white, hence the term"white matter"
- Brain axons are unmylenated, hence the term "grey matter"
- Myelin is laid down by Schwann cells and has two function
- Insulate the axon to allow fine motor control
- Saltatory conduction where the depolarization jumps (saltare is Latin for to jump) from between on Schwann cell to another. That makes the speed of nerve conduction faster
- In humans neurons conduct from 30 to 100 meters/sec
- Integration:
All-or-none and summation
- The All-or-None law means neuron can only fire one way, fully, no fractional firing
- A neuron can be either excited, meaning impulse will continue (EPSP)
- Or a neuron can be inhibited, meaning the impulse will stop (IPSP)
- Notice how either can convey information
- In temporal summation the pre-synaptic neuron fires repeatedly making the post-synaptic neuron more like to fire during its relative refractory period
- In the Temporal Summation movie below, the pre-synaptic neuron must fire twice before the post-synaptic neuron will fire
- In spatial summation several pre-synaptic neurons firing simultaneously make the post-synaptic neuron more like to fire during its relative refractory period
- The Neuron
- Synapses and Neurotransmitters
- Synaptic Transmission
- Neurochemical Messengers
- Acetylcholine (ACh)
- Found in central and peripheral nervous systems
- Involved in muscle action, learning, memory
- Botox destroys ACh and prevents wrinkles
- Curare
- South American poison that affects Acetylcholine synapses
- Causes paralysis and death by asphyxiation
- Formerly used in surgery before anesthesia was developed
- GABA (Gamma Aminobutyric Acid)
- Found in CNS
- Inhibits neurons from firing (IPSPs)
- Low levels of GABA linked to anxiety
- Glutamate
- Most prevalent neurotransmitter
- Excites neurons to fire
- Involved in learning, memory, and detection of rewards
- Linked to:
- Anxiety
- Eating Disorders
- Depression
- Schizophrenia
- Alzheimer
- Parkinson
- Norepinephrine (or Noradrenaline)
- Stress releases it
- Fear symptoms
- Inhibits CNS neurons
- Excites:
- Heart
- Intestines
- Urogenital Tract
- Helps control alertness
- Norepinephrine levels increased by drugs:
- Amphetamines
- Cocaine
- Nicotine
- Dopamine
- Controls voluntary movements
- Affects
- Sleep
- Mood
- Attention
- Learning
- Stimulants drugs activate dopamine receptors
- Low levels associated with Parkinson disease
- Serotonin
- Involved in:
- Sleep
- Mood
- Attention
- Learning
- Low levels associated with depression
- Regulates sleep and wakefulness synergistically with ACh and Norepinephrine
- Involved in:
- Endorphins
- Endogenous opiates
- Shield us from pain
- Elevate pleasure
- Examples:
- Runner's High
- Childbirth
- Shock
- Endogenous opiates
- Oxytocin
- Hormone and Neurotransmitter
- Involved in:
- Lactation and breastfeeding
- Social bonding
- Acetylcholine (ACh)
- Drugs and Neural Transmitters
- The effects of many drugs are effective because they either raise or lower neurotransmitters at specific synapses.
