Transcript Powerpoint slides

Psychology 2606
Dr. David Brodbeck
History and Origins of the Study of
Brain and Behaviour
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The course is about the relationship
between brain and behaviour
This is a question that has involved many
people, philosophers, physicians,
psychologists and neuroscientists
Once we define a couple of terms (notably
‘brain’ and ‘behaviour’) we can look at how
these different groups of people have
looked at the relationship
What is brain?
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Well you can kick it
Tissue
Organ
Is it just that wrinkly
thing in your head?
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Technically yes
However, you cannot
do certain behaviours
without say a spinal
cord
Brain brain brain
So, while the definition of brain really
means just the thing in the head, we will
have to concentrate not only on the brain
itself but on the cerebellum, spinal column
and indeed other parts of the nervous
system if we want to relate the brain to
behaviour.
 The ‘Mind-body’ problem
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The Nervous system
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Central Nervous system (CNS)
Brain, spinal column, cerebellum
 Communication is neural
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Peripheral Nervous system (PNS)
Nerves that make you move basically
 Communication is neural
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How does it work?
Bicep curl for example
 Muscle needs an agonist and an
antagonist
 Motor neuron sends message to bicep to
curl up
 Sensory neuron tells you when to stop
 Simple behaviour LOTS of neurons
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In a Moth’s Ear….
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Moth Ear basically
has two neurons A1
and A2
They are not
frequency sensitive,
but do not respond to
low frequencies
Those would be some tiny Q
tips…..
Do Moths Have Ear Wax?
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A1 is responsive to
intensity
More firing with closer
bat
A2 only fires with very
loud sounds
A2 fires, bat must be
very close
Moths and Bats, Charts and
Graphs
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A1 on the left fires, that
wing beats faster
Moth’s course corrects to
180 degrees from bat
So very and totally cool
A2, go crazy
2 neuron ear can encode
where a predator in in 3
dimensional space!!!
Autonomic Nervous System
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Different communication than in the CNS and
PNS
Not neural, more chemical
Hormones secreted into bloodstream by
‘ductless glands’
Pituitary gland is the master gland
Example, pituitary controls release of pitocin and
oxytocin which start labour
Another example, effects of testosterone on
spatial ability
psychoneuroendocrinology
Behaviour
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And you thought our brain definition was
amorphous…
What is behaviour?
1 : the manner of conducting oneself
2 a : anything that an organism does involving
action and response to stimulation b : the
response of an individual, group, or species to
its environment —be·hav·ior·al or chiefly British
be·hav·iour·al /-vy&-r&l/ adjective —
be·hav·ior·al·ly or chiefly British
be·hav·iour·al·ly /-r&-lE/ adverb
Hmmmmmmmmmm
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Action and response to stimuli eh
Stimuli, well, we tend to think of those as
being external things
 But we can oh imagine pizza, and then have a
reaction….
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An organism, so a plant can behave?
 As a rule, dictionary definitions suck.
 Behaviour is some observable reaction
that has no obvious substance
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OK Mr. smart guy what does
behaviour mean?
That’s Dr. Smart Guy to you….
 Action of an organism having cause and
function
 So, in the moth example, the cause is the
sound, the function is evasion
 This will include both learned behaviour
and inherited stuff
 Not all behaviour has an obvious function
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Some history
First the earth cooled, then the dinosaurs
ruled the world, then they died cuz of
some big meteor, then the people showed
up…
 Even early humans probably wondered
about why we do what we do
 Then we started hanging around in towns
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Aristotle
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Believed that the
heart was the seat of
behaviour
He noted the
importance of the
brain (but it was for
cooling blood he
figured)
British Empiricists
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Thomas Hobbes
(1588-1679)
Contents of mind rest
on experience
John Locke (16321704)
‘white paper’ or tabula
rasa
Rene Descartes
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Descartes said that
we were machines
with a soul
The notion was that
the mind and the
body were separate
Animals have no soul
And yadda yadda yadda….
By the 19th century people were talking
about psychology
 Still the philosophers held sway
 Last half of the 19th century changed this
 The zeitgeist of the time changed
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What the hell does zeitgeist mean?
I don’t speak freaky deaky Dutch Mr.
Goldmember
 The spirit of history
 The enlightenment of the 18th century was
affecting the common person
 Science and technology could explain
everything
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Gesundheit
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Even the origins of
humanity could be
explained without
appealing to religion!
Charles Darwin and
the Origin of Species
So like you could
figure out anything
with science!!
Natural Selection
The Theory of Natural Selection is so
simple that anyone can misunderstand
it…. (Anonymous)
 Charles Darwin (1809-1882) saw three
problems in need of a solution.
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Darwin was not the only one to see these
problems BTW
 Other ‘Naturalists’ were struggling with the
same issues
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Problem the First
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There is change over time in the flora and
fauna of the Earth
What we would commonly call ‘evolution’
today
 The fossil record showed this to be pretty
clear, even to people in the mid 1800s
 This was not controversial in Darwin’s time,
and is not now.
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The Second Problem
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There is a taxonomic relationship among
living things
People were big into classifying stuff
 It was pretty obvious that there was a
relationship between different species
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 Different
birds, different grasses, different cats etc
The Third Problem
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Adaptation
Different kinds of teeth for different animals,
say carnivore ripping teeth and herbivore
grinding teeth
 Different tissues within species
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 Heart
vs. eye etc.
The Solution!
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Natural Selection provides a mechanistic
account of how these things occurred and
shows how they are intimately related.
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It is one of those ‘oh man is that ever easy,
why didn’t I think of that?’ type things.
How’s it work?
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There is competition among living things
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More are born or hatched or whatever, than
survive and reproduce
Reproduction occurs with variation
This variation is heritable
 Remember, there was NO genetics back then,
Chuck knew, he just knew….
 Realized that is wasn’t ‘blending’
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How’s it Work?
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Selection Determines which individuals
enter the adult breeding population
This selection is done by the environment
 Those which are best suited reproduce
 They pass these well suited characteristics on
to their young
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How’s it Work?
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REPRODUCTION is the
key, not merely survival
If you survive to be 128
but have no kids, you are
not doing as well as I am
I have reproduced…
Assuming the traits that
made me successful will
help them then I amore fit
NOW than the 127 year
old guy
This lecture keeps evolving…..
Survival of the Fittest (which Chucky D
NEVER said) means those who have the
most offspring that reproduce
 So, the answer to the trilogy of problems
is:
 ‘Descent with modification from a common
ancestor, NOT random modification, but,
modification shaped by natural selection’
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So cause and function
The causal part of the behaviour definition
refers to the immediate cause, stimuli, that
sort of thing
 Function is over evolutionary time usually
 What does the behaviour accomplish
 How does it increase fitness
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Human evolution
We split from the chimps about 5 million
years ago
 For a long time we were basically not so
hairy short apes
 What happened?
 Diet change, maybe
 Standing up was key
 You have to pump blood up
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Our Brains make us us
If you get a heart so powerful that it can
pump blood up, well you have lots of extra
Oxygen and sugar you can use
 So get a bigger brain!
 See we don’t have big teeth
 We can’t run that fast (without steroids…)
 But, we can outsmart our prey
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Ok so….
So you are saying that big brain means big
smarts right?
 Sorta, encephalization quotient idea
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Food storing vs non storing birds and Hp
volume
Within species?
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Harder to tell