Transcript Neurons: How the brain communicates

Neurons: How the brain communicates
 Neurons – billions used to convey info.
Throughout the body
 Dendrites – take in neurochemical info
 Axon – sends messages to next neuron
– Sends message faster if mylenated
 Damage can occur from injury or disease
– Most common for young adults?
Neurons in Hippocampus
Making Memories
Neuronal Stem Cells
What part of the brain is most related to
memory?
1.
2.
3.
4.
Medulla
Thalamus
Hippocampus
Temporal lobes
0%
1
0%
0%
2
3
0%
4
Divisions of the brain
 The lobes: 1. Frontal (higher cognitive &
motor functioning), 2.Occipital (visual
processing), 3. Temporal (auditory
processing), & 4. Parietal (sensations of the
skin and muscles)
 Right hemisphere
– visual-spatial processing
 Left hemisphere
– language production (Brocha’s area)
– comprehension (Wernicke’s area)
How the brain works
 Corpus callosum – connects the two hemispheres
of the brain and allows them to communicate
– Severed (surgically) in some patients with severe
forms of epilepsy to prevent grand mal seizures
from spreading to both hemispheres
 Roger Sperry’s work on split brain patients
– Each hemisphere has unique functions and can
be autonomous
– Hemispheric isolation creates potential for errors
 Migration of functioning – transfer of functioning
that can occur when part of the brain is damaged
(more likely if patient is young)
Conditioning in everyday life
 Cancer patients receiving trials of chemotherapy show a
weakening of their immune system when exposed to the
hospital room where they received chemotherapy
– Can we condition an increases in the immune system?
 Placebo effects with drugs – If a pill has worked for you
before a similar pill (even an inert substance) can not only
cure a headache, but actually result in neurochemical
changes in your body
 Behavioral change: A Clockwork orange, reconditioning
prisoners, buzzer pants, etc.
 Salivating to the golden arches, nausea to a specific drink,
etc.
Conditioning dogs and rats
 Watson & Raynor (1920) trained a young infant (Little Albert) so that he
would e afraid of a rat.
 Before conditioning
– Present white rat – no fear (neutral stimulus)
– Loud noise – fear (unconditioned response)
 Conditioning
– Pair the white rat (neutral stimulus) with the loud noise (unconditioned
stimulus)
 After conditioning
– White rat = fear (conditioned response)
– The white rat is now a conditioned stimulus
 Albert generalized the fear response to other white furry objects like a
white rabbit and even a Santa’s beard
 See also Pavlov’s work (text)
Key concepts
 What happens if we keep exposing Albert to the rat with no
loud sound? Eventually…
 Extinction - CS no longer produces the CR
 Spontaneous recovery - after a break, the previously
extinct CS produces the CR
 Higher order conditioning - a CS is paired with another CS
to get the CR
 What happens if we use something similar to a white rat?
(a lesson from alcohol poisoning)
Key concepts - continued
 Generalization - producing the same CR for a similar CS
(e.g., all alcohol; anything that looks like a white rat)
 Discrimination - produces a CR for only a very specific CS
(e.g. only “Mad Dog” wine; only the white rat)
 One time conditioning (Garcia effect) - learning occurs after
a single pairing (e.g., sheep and wolves)
– Why would this be adaptive for aversive CRs?
– This can occur even for reinforcers and lead to nonproductive behavior (e.g., superstitious behavior)
Operant conditioning
 To explain most of your day-to-day behavior it is also
necessary to consider non-reflexive actions (not just
salivating & fears)
 Law of effect – every behavior has a consequence, and the
consequence determines if the behavior will re-occur
(temporal association is no longer required)
 Reinforcement - anything that increase the incidence of the
behavior to which it is linked
 Punishment - anything that decreases the incidence of the
behavior to which it is linked
 Positive - to add
 Negative - to remove
Possible examples of reinforcers and
punishers
Reinforcer
Positive
To give praise, love,
attention, money,
etc.
To remove an
aversive stimulus
Negative like pain, noise, etc.
Punisher
To give a shock, a
spanking, a fine, etc.
To remove
something valued
like freedom,
attention, etc.
Delivery (Schedules) of reinforcement &
punishment
 Continuous - best way to acquire a new behavior (or
extinguish an existing behavior)
– Why not ideal to maintain the new learning?
 Ratio - number of responses for the reinforcement
 Interval – there is an interval of time before the next
response is reinforced/punished
 Variable - changing schedule
 Fixed - stable schedule
Other schedules
Fixed
Interval
Ratio
Variable
Pay checks, boss
who “checks in” at
9am and 4pm, etc.
- lengthy breaks until
interval approaches
(bursts of activity)
Real estate agent,
busy phone line, etc.
- slow but steady
rate (busy phone)
Assembly line
worker
- decrease in work
after reinforced
Slot machines
- very productive
schedule with
minimal pausing
Behavioral Applications
Treatment of OCD & Simple phobias – Phobias are intense
fears (or non-normative fears) that lead to dysfunction
– Systematic desensitization – developed by J. Wolpe
 Establish a fear hierarchy – from least feared to most
feared
 Systematically expose the individual to each stimulus
on the fear hierarchy beginning with the lowest (up to
several months)
 Must be in a relaxed state while exposed to the
stimulus
 Must NOT remove the feared stimulus until fear is
diminished otherwise the fear is reinforced
 For OCD – have obsession with response prevention
Personality: A stable pattern of behaviors, cognitions,
and affect
What determined your personality? (explanation)
Some examples..
 Internal and unknown conflicts?
– Freud and the psychodynamic movement (ID, Ego, Superego)
defense mechanisms of denial, intellectualization, sublimation,
projection, and reaction formation
 Biological processes?
– Eysenck and arousal in the ARAS (introversion/extraversion)
How do we measure personality? (description)
- Early examples were decidedly non-scientific
Assessment
Roots of Assessment
Early attempts..
 Palm reading
 Astrology - stars as gods vs. planets
All of these rely on…
Barnum effect - broad and slightly positive statements;
– Most non-standardized, unreliable, and non-validated procedures
rely on the Barnum effect (Stock statements - true in all
circumstances; and Fishing statements – general statements that
can be interpreted in many ways e.g., “you’ve experienced a loss”)
– Research (Glick, 1985) suggests that people are more likely to
believe Barnum-type false feedback vs. real personality
assessments.
Morphological assessments: From the head to the
body
 Phrenology (Gall, early 1800s) – skull shape = personality
 Sheldon’s body types (1950)
– Based on photographs of all incoming freshmen at Ivy league
schools in the 1930s
– Endomorph – jolly/happy, lazy
– Mesomorph – dominant, athletic
– Ectomorph – smart, shy
 Lomboso’s criminal character (L’uomo delinquente)
Assessment in the 20th century
 Psychodynamic methods: word association, TAT,
Rorschach, etc.
 MMPI - developed in 1940 using an empirical approach,
revised in 1989 (MMPI-2) and has 567 T/F items
– Most widely used inventory in clinical settings
– items generally lack face validity (not obvious)
– validity scales (lie, defensiveness, infrequency)
– Assesses m/f, Si, Hs, Pa, etc. (psychopathology=
personality)
 NEO-PI – developed for use in the non-clinical population
– Neuroticism, Extraversion, Openness to new
experience, Agreeableness, & Conscientiousness
– What does it mean to be neurotic?
– Consequences of having internal control beliefs on
health and happiness (old age home studies)
Intelligence - what is it?
 Cognitive abilities such as memory, vocabulary, reasoning, general
knowledge, speed of responding, etc.
 Weschler Adult Intelligence Scale (WAIS-III)
– Verbal and Performance IQ
– Mean IQ = 100, SD = 15
– Like all IQ measures, it is considered to be culturally biased (no
such thing as a culture free test)
 Gould: Intelligence does not reflect innate skills (see above areas), nor
is intelligence unchangeable, nor does it = IQ!
 Broader definitions of intelligence: Gardner’s multiple intelligences
(e.g.., abilities in music, art, language, social skills, coordination, etc.)
 Creativity - a way to assess alternative forms of intelligence (flexibility
in how one thinks about a problem- allows for novel responses and
divergent thinking – example items for the consequences test)
Stunted intellectual development
Is associated with several disorders including Autism:
 Includes the following: extremely low IQ, minimal verbalizations,
isolative, repetitious (rocking) and sometimes self-damaging (head
banging) behavior
 More common in males, but the females who do get it tend to be more
severe cases (Overall: 1 in 10,000)
Savant syndrome
 Very rare (only 1% of all autistic individuals: Overall: 1 in a million)
 An extraordinary ability (either in absolute or relative to daily
functioning), severe cognitive deficits, over attention
Stimulus over-selectivity – over attention to only one aspect of a stimulus
(can explain both autism and savant syndrome)
Biases and heuristics in judgment
 General rules we apply in reasoning to be more efficient (can also
result in erroneous conclusions when improperly applied)
 What percentage of crimes are considered violent crimes?
– The availability heuristic
 Who is most likely to be a quiet individual who likes classical music and
cognac? The chair of the UNC music dept or a taxi driver?
– The representative heuristic (ignores base rates)
 What is your chance of getting AIDS in the next two years? What is the
chance of someone of the same age/gender doing similar behaviors as
you getting AIDS in the next two years?
– Overconfidence bias
Biases and heuristics in judgment – cont.
 What are the next three numbers in the sequence (2,4,6, _,_,_)?
– Confirmation bias
 The odds of winning at black jack are 50%. Assuming you have just
lost 10 hands in a row, what are your odds of winning the next one?
– Gambler’s fallacy (luck will change) – in reality, these are random
and unrelated events. So luck doesn’t have to change.
 When an all-star team plays a regular team, who should win?
– Fallacy of composition – the whole is = sum of its parts
 Buying beef with 25% fat or 75% fat free?
– Framing effects – context provides information that results in
different conclusions