Brain Evolution

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Brain Evolution
In the distant future psychology will be based
on a new foundation, that of the necessary
acquirement of each mental power and capacity by
gradation. --Charles Darwin, 1859
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What is this course about?

• The what?
• The why?

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The what

• What do we know about the structures of the
  brain? What are the functions of the different
  brain areas? How can neuroimaging inform us?
• Evolutionary cognitive neuroscience
• Biological mechanisms underlying cognition, as
  studied from an evolutionary theoretical
  perspective
• Platek et al. (Eds.) (2007). Evolutionary
  Cognitive Neuroscience. Cambridge, MA. MIT Press.

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The why

• What is the biological reason for gossip?
• For laughter? For the creation of art?
• Why do dogs have curly tails?
• What can microbes tell us about morality?
• Wilson, D. S. (2007). Evolution for everyone How
  Darwins theory can change the way we think about
  our lives. New York, NY. Delacorte Press.

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Taking a Comparative PerspectiveIntegrating
Neuroscience, Cognitive Psychology,
Evolutionary Biology
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Comparative Psychology

• Uncovering similarities differences between
  human animal behavior
• Comparative cognition concerned with comparing
  cognitive processes
• Wasserman Zentall (2006). Comparative
  Cognition Experimental Explorations of Animal
  Intelligence. Oxford University Press.

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Why compare brains?
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What is Comparative Psychology?

• the comparative study of brains and behavior in
  human and nonhuman animals
• Biological psychology (aka behavioral
  neuroscience) relates behavior to bodily
  processes, especially the workings of the brain
• Neuroscience the study of the brain
• We compare species to learn how the brain and
  behavior have evolved
• Continuity of behavior and biological processes
• Species-specific differences in behavior and
  biology

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Questions for you

• Are some species more evolved than others?
• Does evolution have a goal?
• Can we say that humans (or other animals) have
  adapted to their current environment?

http//rainbow.ldeo.columbia.edu/courses/v1001/ear
th1.gif
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Common Misunderstandings

• Human behavior is genetically determined
• If its evolutionary, we cant change it
• Current mechanisms are optimally designed
• Buss, D. M. (2004). Evolutionary Psychology The
  New Science of the Mind. Boston, MA. Pearson.

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Natural Selection

• There is variation in traits.
• There is differential reproduction.
• There is heredity.
• End result The more advantageous traits, that
  allow for more offspring, become more common in
  the population

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Three Products of Evolution

• Adaptations
• Ex umbilical cord
• By-products
• Ex belly button
• Noise
• Ex shape of a persons
• belly button
• Buss, D. M. (2004). Evolutionary Psychology The
  New Science of the Mind. Boston, MA. Pearson.

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Other examples of adaptations.
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Examples of by-products
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Proximate vs. Ultimate Causation

• Proximate cause
• event immediately responsible
• HOW something works
• Ultimate Cause
• The real reason something occurred
• Evolutionary cause
• WHY something works

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Example

• The ship sank.
• Proximate cause water entered the hull and the
  ship became heavier than the water which
  supported it, so it couldnt stay afloat
• (HOW it happened)
• Ultimate cause ship hit a rock which tore open
  the hull
• (WHY it happened)

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Example

• We can see.
• Proximate cause light enters the cornea, moves
  through the pupil then hits the retina and is
  transmitted to the brain
• (HOW it happens)
• Ultimate cause it is adaptive to be able to see
  things around youimproved survival/reproduction
• (WHY it happens)

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Adaptations

• Traits formed directly by selective pressures
• Dont necessarily increase reproductive success
  in current environment

http//evolution.berkeley.edu/evosite/evo101/image
s/katydid_225.jpg
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Adaptations

• Current environment is different from ancestral
  environment
• Example trees seeds on sidewalk

http//static.flickr.com/54/131303743_d14f0aba83.j
pg
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Adaptations

• Current environment is different from ancestral
  environment
• Example North American pronghorn antelope

http//www.kvmr.org/pgm_images/pronghorn.jpg
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Adaptations

• Current environment is different from ancestral
  environment
• Example Obesity!

http//www.zapad.cz/fotos/zdravi/cholesterol/fat_m
an_large.jpg
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Natural Selection

• Works only in relation to what has evolved,
  therefore many features seem poorly designed
• Ex human throat
• Not all aspects of living organisms are
  adaptations
• Ex Fox following snow tracks to hen house

http//www.childhoodhealth.com/images/strep_throat
.jpg
http//www.cameraontheroad.com/photos/mammals/foxc
loseup.jpg
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Is there anything that natural selection cannot
explain?

• Hints

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Sexual Selection

• Natural selection has trouble explaining some
  things
• creativity, art, language, music, morality
• Whats the survival value?
• Sexual selection our minds evolved not as
  survival machines, but as courtship machines
• Miller, G. (2001) The mating mind How sexual
  choice shaped the evolution of human nature.

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Intersexual selection Preferential Mate Choice

• What were looking for Whats looking for us

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Different Levels of Analysis
Brain structures
Behavior
(Rosenzweig et al., 2005)
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Neuroscience is virtually an evolutionary-free
zone

• Is it not reasonable to anticipate that our
  understanding of the human mind would be aided
  greatly by knowing the purpose for which it was
  designed? (Williams, 1966, p.16)
• WHY???
• Psychology as a disparate set of fields

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Metatheory

• Evolutionary theory as a metatheoretical
  framework within which all psychological science
  can be organized.
• Theory
• Testable hypotheses
• Predicts

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Standard Social Science Model (SSSM)

• "Much of what is commonly called 'human nature'
  is merely culture thrown against a screen of
  nerves, glands, sense organs, muscles, etc."
  (Leslie White, 1949, cited in Degler, 1991, p.
  209)
• What does this mean? Do you agree???
• Organisms possess general-purpose learning
  mechanisms
• Biology plays little if any role in the
  manifestation of behavior
• "blank slate" or "cultural determinist"
  perspectives
• However, many studies have demonstrated this is
  not the case

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Standard Social Science Model (SSSM)

• Much evidence against the SSSM (there is a
  human nature!)
• Example
• Prepared learning
• Difficulty to fear modern threats (e.g. guns
  cars) vs. Effortless learning to fear ancient
  threats (e.g. snakes spiders) (Ohman Mineka,
  2001)
• All learning is a consequence of carefully
  crafted modules dedicated to solving specific
  evolutionary problems (Platek et al., 2007,
  p.xiv)

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Environment of Evolutionary Adaptedness

• What is this?
• Not a place or time in history, but a statistical
  composite of the selection pressures of ancestral
  past, the adaptations that characterized that
  past
• Pleistocene (1.81-.01mya) human EEA

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Evolutionary Perspective

• How would you describe Evolutionary Psychology?
• Evolutionary biology cognitive psychology
• Mental psychological traitssuch as memory,
  perception, or languageare adaptations
• i.e., the functional products of natural
  selection
• Cognition has a functional structure (the brain)
  that has a genetic basis
• be universally shared
• solve problems of reproduction

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Modularity of the brain

• Modules separate innate structures in the
  brain with evolutionary-developed functions
  units of mental processing that evolved in
  response to selection pressures
• Language acquisition device (Noam Chompsky)
• Cheater detection mechanism (Cosmides Tooby)
• Fusiform Face Area (Kanwisher et al.)

Can you think of other modules our brains might
have?
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Basic Principles

• 1. The brain is a physical system that functions
  as a computer.
• 2. Our neural circuits were designed by natural
  selection to solve problems that our ancestors
  faced during our species' evolutionary history.
• Stone age minds

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Basic Principles

• 3. Consciousness is just the tip of the iceberg
  most of what goes on in your mind is hidden
• Ex vision
• Ex attraction
• http//www.pbs.org/wgbh/evolution/library/01/6/
  l_016_08.html

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Basic Principles

• 4. Different neural circuits are specialized for
  solving different adaptive problems.
• Localization of function specific brain regions
  are responsible for various types of experience,
  behavior, and psychological processes.
• Examples
• function location
• vision occipital lobe
• audition top of temporal lobe
• speech comprehension "Wernicke's" area
• voluntary movement back edge of frontal lobes
• bodily sensations front edge of parietal lobes
• emotion regulation limbic system