2. Biological Psychology
•
Study of the physiological, evolutionary, and developmental
mechanisms of behavior and experience
– emphasis on the study of areas and sub-areas of the
brain
– brain area’s function depends on communication among
neurons, the “building blocks of behavior”
– neuron activity somehow produces behavior and
experience
3. Figure 1.1
Figure 1.1 A dorsal view (from above) and a ventral view (from below) of the human brain. The brain
has an enormous number of divisions and subareas; the labels point to a few of the main ones that are
visible from outside.
4. Biological Explanations of Behavior
•
•
•
•
Physiological: relates a behavior to the activity of the brain
and other organs (area of brain enables bird to sing)
Ontogenetic: describes the development of the structure or
behavior (why genes and environment both necessary for
bird to sing)
Evolutionary: examines a structure or a behavior in terms of
evolutionary history (two different species of birds with similar
songs have same ancestor)
Functional: describes why a structure or behavior evolved as
it did (singing improves bird’s chances of mating)
6. Frank Johnson
Program in Neuroscience
Florida State University
Why Birds Sing
Motor Control of Neural and Vocal
Development in Songbirds
7. Key Features:
• Auditory input relayed through HVC
• Two pathways emanate from HVC, both lead to RA
8. Key Features:
• Song is learned by males during juvenile development
• Sexual dimorphism in brain also emerges during development
• Growth of song regions in males correlates with vocal learning
9. Does song learning show a practice effect?
Key features
Daily song production peaks during plastic song and
song crystallization (avg total during learning = 50,000)
Birds with the greatest song production during plastic
song had the highest stereotypy scores as adults
10. Mind-Body Problem
•
•
Dualism: mind and body are different kinds of substances,
that exist independently but somehow interact
– René Descartes proposed that mind and brain interact in
the pineal gland
Monism: there is only one kind of existence
– materialism: everything is material or physical
– mentalism: only the mind exists
– identity: mental processes are the same thing as certain
kinds of brain processes, but described in different terms
(e.g., fear is the same as the accompanying pattern of
neural activity in the brain)
11. Mind-Body Problem cont.
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•
•
What is consciousness and how is it produced?
Hard problem: the question of why and how any kind of brain
activity is associated with consciousness
– Chalmers (1995): consciousness is a fundamental
property of matter and cannot be reduced further
Easy problems: determining the difference between
wakefulness and sleep, or identifying brain mechanisms that
enable us to focus our attention
– Dennet (1991, 1996): When we answer all of the easy
problems, the hard problem will go away
12. Mind-Body Problem cont.
•
•
Research may not solve problem soon because consciousness
is not directly observable
– I know that I am conscious but I can only infer that you have
conscious experience
– solipsism: the belief that only I exist
Where and when does consciousness occur?
– do all animals have conscious experiences? plants? rocks?
– when does the human embryo experience consciousness?
– could we build a robot that experiences consciousness?
13. Genetics of Behavior
•
•
Mendel (19th century): inheritance occurs through genes
– chromosomes are strands of genes, normally in pairs
– genes are units of heredity that maintain their structural
identity across generations
– a genotype is an expression of a gene pair (e.g., BB, Bb,
or bb)
Deoxyribonucleic acid (DNA):
– when DNA exists as a double strand in a helix, it makes
up a chromosome
– when DNA exists in a single strand, it serves as a
template for the synthesis of RNA
14. Figure 1.6
Figure 1.6 How DNA controls the development of an organism. The sequence of bases along a strand
of DNA determines the order of bases along a strand of RNA; RNA in turn controls the sequence of amino
acids in a protein molecule.
15. Genetics of Behavior cont.
•
Genotype expression (B=brown eyes; b=blue eyes)
– homozygous: having an identical pair of genes on two
chromosomes (BB or bb)
– heterozygous: having an unmatched pair of genes on two
chromosomes (Bb)
– dominant gene: expressed in either the homozygous or
heterozygous condition (Bb or BB will be expressed as
brown eyes)
– recessive gene: only expressed in the homozygous
condition (bb is the only condition where blue eyes will be
expressed)
16. Figure 1.7
Figure 1.7 Four possible outcomes of a mating between parents who are heterozygous for a given
gene (Tt). A child in this family has a 25% chance of being homozygous for the dominant gene (TT), a 25%
chance of being homozygous for the recessive gene (tt), and a 50% chance of being heterozygous (Tt).
17. Genetics of Behavior cont.
•
•
When genes are close together on the same chromosome
they are usually inherited together, e.g., BC or bc
– “crossing over” occurs during reproduction when a pair of
chromosomes exchange parts with each other, e.g., BC
and bc become Bc and bC
Sex-linked genes on X and Y chromosomes
– male (XY) has only one X chromosome and will always
express X-linked recessive genes (8% have red-green
color blindness)
– female (XX) will express a recessive gene only if it occurs
on both of her X chromosomes (1% have color blindness)
18. Genetics of Behavior cont.
•
•
Sex-limited genes
– present in both sexes but effect is limited or almost limited
to one sex (chest hair, breast size)
– genes expressed only after activation by sex hormones
Sources of variation
– recombination: some genes from two parents combine to
yield characteristics not found in either parent
– mutation: a random change in a single gene
– crossing over creates unique characteristics not found in
either parent
19. Genetics of Behavior cont.
•
Heritability
– an estimate of how much of the variance in a population
characteristic is due to heredity (ranges from 0 to 1)
– if 0, heredity accounts for none of the observed variations
in that characteristic (e.g., in a population with similar
genes, most differences are due to environment)
– if 1, heredity accounts for all of the variations in that
characteristic (e.g., in identical environments most
differences are due to genes)
– if 0.5, both components contribute
20. Genetics of Behavior cont.
•
How heritability is determined
– compare similarities in monozygotic twins versus
dizygotic twins
– compare adopted children with their biological and
adoptive parents
– findings support high heritability in many areas but we
may underestimate the effect of environment and
interaction between geneotype and environment
21. Genetics of Behavior cont.
•
Can heritability be modified?
– PKU, caused by genetic inability to metabolize
phenylalanine, can be minimized with proper diet
22. Figure 1.8
Figure 1.8 Prenatal development of monozygotic and dizygotic twins. In most cases, monozygotic
(identical) twins develop in a single placenta and have the same blood supply. Dizygotic (fraternal) twins
develop in separate placentas. Therefore, monozygotic twins have the sane prenatal environment as well
as the same genetic inheritance, and dizygotic twins differ in both respects.
23. Evolution of Behavior
•
•
•
Change over generations in the frequencies of various genes
in a population
Change occurs through mutations, recombinations and any
new genes that are successfully reproduced
Artificial selection limits reproduction to animals that possess a
desired trait, ensuring its survival
24. Misunderstandings about Evolution
•
•
•
•
“Lamarckian evolution” is mistaken belief that we acquire
characteristics through use and lose them through disuse.
If “survival of fittest” no longer applies, has evolution stopped?
– no, reproduction, not survival is key
Does evolution mean improvement?
– maybe; your genes got you here but they may not be
advantageous tomorrow
Does evolution act to benefit the individual or the species?
– neither; it acts to spread the genes
25. Sociobiology/Evolutionary Psychology
•
Seeks functional explanations for why a behavior is useful
and is favored by natural selection
– why some animals have better color or peripheral vision
– why we cycle through stages of sleep
– why mammals and birds use most of their energy to stay
warm
– why different species have different eating habits
– why people die at different rates
– why more men than women enjoy casual sex with multiple
partners
26. Sociobiology/Evolutionary Psychology cont
•
•
How does sociobiology explain altruistic behavior?
– a gene that encourages altruism would help others survive
to reproduce
– humans exhibit altruism but uncommon in non-humans
– reciprocal altruism and kin selection may help spread gene
Sociobiology can be criticized when practitioners assume that
a behavior is adaptive and then propose an explanation
without testing it
27. Reasons for Animal Research
•
•
•
•
Underlying mechanisms of behavior are similar across
species and sometimes a nonhuman species is easier to
study
We are interested in animals for their own sake
Learning about animals sheds light on human evolution
Legal or ethical restrictions prevent the use of human
participants in certain experiments
28. Figure 1.12
Figure 1.12 Brains of several species. The general plan and organization of the brain are similar for all
mammals, even though brain size varies from species to species.
29. The Ethical Debate on Animal Research
•
•
•
•
Some experiments subject animals to brain damage,
electrode implantation, injections for drugs or hormones
Minimalists agree that some animal research is acceptable,
but wish to minimize it
Abolitionists want all research on animals to stop
Principles of moderation and compromise are now the legal
standard in the US
30. Careers in Biological Psychology for Psychologists (PhDs)
•
•
•
•
Behavioral neuroscientist: investigates how functioning of the
brain and other organisms affect behavior
Neuroscientist: studies anatomy, biochemistry, and
physiology of the nervous system
Neuropsychologist: conducts behavioral tests to determine
what brain damaged people can and cannot do
Psychophysiologist: measures heart rate, breathing rate
brain waves, and other body processes that change as a
function of people’s activities and information processing
31. Careers in Biological Psychology for Physicians (MDs)
•
•
•
Neurologist: treats people with brain damage or diseases of
the brain
Neurosurgeon: performs brain surgery
Psychiatrist: helps people with emotional distress or
troublesome behaviors, sometimes using drugs or other
medical procedures
