1

CHAPTER

2The Biological Basis of Behavior

Links to Learning Objectives

ENDURING ISSUES IN THE BIOLOGICAL

BASIS OF BEHAVIOR

NEURONS: THE MESSENGERS

Types of neurons

Transmitting information

Synapse and neurotransmitters

Neural plasticity and neurogenesis

THE CENTRAL NERVOUS SYSTEM

Parts of the brain and their functions

Tools for studying the brain

Spinal cord

THE PERIPHERAL NERVOUS

SYSTEM

Somatic and autonomic nervous systems

Sympathetic and parasympathetic nervous systems

THE ENDOCRINE SYSTEM

Endocrine glands and their hormones

GENES, EVOLUTION, AND BEHAVIOR

Heredity-environment

Passing traits from generation to generation

Methods for studying genes and behavior

Key ethical issues

Natural selection

Enduring Issues

To what extent

is behavior caused by

internal processes,

as opposed to

environmental

factors?Diversity-

Universality

Stability-Change

Mind-Body

Nature-Nurture

Person-Situation

2

Enduring Issues

To what extent does

heredity affect behavior?

Diversity-

Universality

Stability-Change

Mind-Body

Nature-Nurture

Person-Situation

Enduring Issues

Does the nervous

system change due to

experience?

Diversity-

Universality

Stability-Change

Mind-Body

Nature-Nurture

Person-Situation

Enduring Issues

Are there differences

between men and women in the

way that the brain works?

Diversity-

Universality

Stability-Change

Mind-Body

Nature-Nurture

Person-Situation

3

Enduring Issues

What is the connection

between what we experience

and our biological

processes?

Diversity-

Universality

Stability-Change

Mind-Body

Nature-Nurture

Person-Situation

Psychobiology and Neuroscience

Psychobiology:

Focuses on biological

bases of behavior and

mental processes

Neuroscience:

The study of the brain

and the nervous system

Neurons: The Messengers

4

Complex

network of

cells that

carry

information to

and from all

parts of the

body

e r v o u ss y s t e m

The Neuron

Terminal buttons

Axon

Cell body (soma)

Myelin

LEARNING OBJECTIVE: Describe a typical neuron. Distinguish between afferent,

efferent, and association neurons.

Dendrites

Three Types of Neurons

Afferent

(sensory) neurons

Efferent

(motor) neurons

Association

neurons

(interneurons)

5

Mirror Neurons“Found in the brains of humans and other primates, mirror neurons appear to

play a key role in how a primate’s brain is wired to mimic the sensations and

feelings experienced by other related animals and, thus, to identify and

empathize with them (Ramachandran, 2005; Rizzolatti et al., 2008).”

– Pages 42-43 (Morris & Maisto)

The Neural Impulse

LEARNING OBJECTIVE: Describe how neurons transmit information, including the

concepts of resting potential, polarization, action potential, graded potential,

threshold of excitation, and the all-or-none law.

All-or-None Law

The neuron either

fires completely

or it does not fire

at all.

6

The Synapse

LEARNING OBJECTIVE: Describe the parts of the synapse and the role of

neurotransmitters in the synapse.

Terminal button

Neurotransmitters

Applying Psychology

• Caffeine

• Cocaine

• Antidepressants

• Botulism

• Black widow spider

• Antipsychotics

7

Effects of Cocaine

Neural Plasticity and Neurogenesis

Neural plasticity:

Experience can change

the brain structurally

and chemically.

• Rosenzweig (1984)

Neurogenesis:

Adult brains can

produce new

brain cells.

LEARNING OBJECTIVE: Explain “neural plasticity” and “neurogenesis.”

Source: From “Brain changes in response to experience” by M. R. Rosenzweig, E. L. Bennett, and M. C. Diamond. Copyright © 1972, Scientific American, Inc.

The Central Nervous System

8

The Organization of the Nervous System

PERIPHERAL

Autonomic Somatic

Parasympathetic Sympathetic

Brain

CENTRAL

Spinal Cord

Central Nervous System

Brain

CENTRAL

Spinal Cord

The Brain

The human brain is the

product of millions of

years of evolution in

three stages:

• Central core

• Cerebral cortex

• Limbic system

LEARNING OBJECTIVE: Identify the parts of the brain and their function. Explain what

is meant by “hemispheric specialization” and the functional differences between the

two cerebral hemispheres.

9

The Central Core

Hindbrain

Midbrain

Thalamus

Hypothalamus

Reticular formation

Structures in the Hindbrain

Outer surface

of the two

cerebral

hemispheres

that regulates

most complex

behavior

e re b ra lc o r t e x

10

Four Lobes of the Cerebral Cortex

Both the left and right hemispheres can be

roughly divided into four sections.

The Limbic System

Limbic system: Ring of structures

that plays

a role in learning

and emotional

behavior

11

Hemispheric Specialization

The Split-Brain Experiment

The corpus callosum is sometimes severed to reduce seizures.

• Left visual field right hemisphere

• Right visual field left hemisphere

Broca’s Area & Wernicke’s Area

12

Handedness“A common misconception is that hemispheric specialization is related to

handedness…many people mistakenly believe that in left-handed people the

right hemisphere governs language, analytic, and sequential tasks, whereas the

left hemisphere dominates in visual, spatial, and nonverbal tasks. The fact is

that speech is most often localized in the left hemisphere for both right- and

left-handed people.”

– Page 59 (Morris & Maisto)

• Microelectrode techniques

• Macroelectrode techniques

– EEG

• Structural imaging

– CAT or CT scanning

– MRI

• Functional imaging

– EEG imaging

– MEG, MSI

– PET scanning

– fMRI

Tools for Studying the Brain

LEARNING OBJECTIVE: Discuss how microelectrode techniques, macroelectrode

techniques, structural imaging, and functional imaging provide information about the brain.

The Spinal Cord

LEARNING OBJECTIVE: Explain how the spinal cord works.

Spinal cord:

• Complex cable of neurons

that runs down the spine,

connecting the brain to most of

the rest of the body

• Functions as a “communication

superhighway”

13

The Spinal Cord and Reflex Action

Motor neurons

Sensory neurons

Interneurons

The Peripheral Nervous System

Peripheral Nervous System

Parasympathetic

PERIPHERAL

Autonomic

Sympathetic

Somatic

14

Peripheral Nervous System

Peripheral nervous system

(PNS): Links the brain and

spinal cord to the rest of

the body

• Afferent neurons

• Efferent neurons

LEARNING OBJECTIVE: Identify the peripheral nervous system and contrast the

functions of the somatic and autonomic nervous systems.

PERIPHERAL

Autonomic Somatic

Subsystems in the PNS

PERIPHERAL

Autonomic Somatic

LEARNING OBJECTIVE: Explain the differences between the sympathetic and the

parasympathetic nervous systems.

Parts of the Autonomic Nervous System

Parasympathetic

PERIPHERAL

Autonomic

Sympathetic

Somatic

15

Autonomic NS: Sympathetic

“Fight or flight”

Source: Adapted from General Biology, revised edition, 1st edition by Willis Johnson, Richard A. Laubengayer, and Louis E. Delanney,

Copyright © 1961. Reprinted with permission of Brooks/Cole, an imprint of the Wadsworth Group, a division of Thomson Learning.

Autonomic NS: Parasympathetic

Source: Adapted from General Biology, revised edition, 1st edition by Willis Johnson, Richard A. Laubengayer, and Louis E. Delanney,

Copyright © 1961. Reprinted with permission of Brooks/Cole, an imprint of the Wadsworth Group, a division of Thomson Learning.

“Rest and digest”

The Endocrine System

16

The Endocrine System

LEARNING OBJECTIVE: Describe the endocrine glands and the way their hormones

affect behavior.

Genes, Evolution, and Behavior

Behavior

Genetics

Genes, Evolution, and Behavior

Two different but related fields contribute to

the understanding of the influence of heredity

on behavior:

LEARNING OBJECTIVE: Distinguish between genetics, behavior genetics, and

evolutionary psychology.

Evolutionary

Psychology

17

LEARNING OBJECTIVE: Differentiate between genes, chromosomes, DNA, and the human genome. Describe what is meant by dominant and recessive genes, polygenic inheritance, and genotype vs. phenotype.

Genetics

B = dominant

gene

Transmission of Eye Color

b = recessive

gene

Behavior Genetics

Animal behavior genetics

• Strain studies

• Selection studies

LEARNING OBJECTIVE: Compare and contrast

strain studies, selection studies, family studies,

twin studies, and adoption studies as sources

of information about the effects of heredity.

18

Behavior Genetics

Human behavior genetics

•Family studies

•Twin studies

– identical twins

– fraternal twins

•Adoption studies

Average Risk of Schizophrenia Among Biological Relatives of People with Schizophrenia

Source: From The Origins of Madness by Irving I. Gottesman, Henry Holt and Company, LLC, 1991, p. 96.

Social Implications

New challenges have arisen as a result of our better understanding of genes.

LEARNING OBJECTIVE: Identify the key ethical issues that arise as society gains more

control over genetics.

• Modern prenatal screening

can detect genetic defects;

do parents have the right

to abort because of this?

• Over-simplified reporting

of genetic technologies in

mass media can lead to

misinterpretation of

complex research findings.

19

Evolutionary Psychology

Evolutionary psychology examines adaptive value of behaviors from an evolutionary perspective.

• Darwin’s natural selection

LEARNING OBJECTIVE: Describe how

evolutionary psychologists view the

influence of natural selection on human

social behavior.

Charles Darwin

Lecture Activities

If the neural

impulse fires

with same

“strength”

every time it

fires, how can

you tell the

difference among

different stimulus

intensities?

20

?!Peer Instruction

I’ve often heard that people only use 10% of their brain. However, even a relatively simple task like playing a piano or even just tapping along to music requires many parts of the brain to be active — well over 10%. In fact, I’ll bet that you have a tough time figuring out which part of the brain would most likely NOT be activated by playing the piano?

A. Pons

B. Pituitary gland

C. Hippocampus

D. Thalamus

On the next slide, you

will read about three

psychological scenarios.

In small groups, discuss

which brain areas/systems

are probably being

activated in these

scenarios.

Shandra is a painter. She is standing by her easel. The window is open and she can smell the jasmine flowers in her yard. She is painting with her right hand. She can hear her children playing in the background.

Melanie is a police officer. She is preparing for her rank-advancement exam. It’s late at night. She is reading through some material and viewing pictures related to brutal murder cases. She is drinking coffee and eating a sandwich.

James is a football player. He is the quarterback in a tough game and the home crowd is yelling and screaming. It’s the fourth quarter and James is tired and sweating as he goes up to hike the ball. After hiking the ball, he and his teammates execute some very complicated running and passing routes to execute a play.

21

Split-Brain Experiment

Sperry and Gazzaniga devised a creative experiment to test hemispheric functioning. In this experiment, visual stimuli were shown to either the LEFT or RIGHT visual fields of split-brain patients.

On the next slide, you will see a red “X.” Stare at the X until you are asked to provide a verbal response.

Trial #1(Click anywhere to begin)

X

CONTINUETRY AGAIN

What did you see?

22

Trial #2(Click anywhere to begin)

X

CONTINUETRY AGAIN

What did you see?

I saw nothing.How do you think a split-brained

patient would respond when asked to

identify an object flashed to the LEFT

VISUAL FIELD?

It’s a ball!

Given what you now know about how the brain

processes information from the two visual fields,

how do you think a split-brained patient would

respond when asked to identify an object flashed

to the RIGHT VISUAL FIELD?

23

In small groups, discuss how the sympathetic NS functions help out in a “fight or flight” situation. What are the implications when the sympathetic NS remains active for extended time periods?

Source: Adapted from General Biology, revised edition, 1st edition by Willis Johnson, Richard

A. Laubengayer, and Louis E. Delanney, Copyright © 1961. Reprinted with permission of

Brooks/Cole, an imprint of the Wadsworth Group, a division of Thomson Learning.

Acknowledgments

Slide # Image Description Image Source

text template upside down blue sky & grass©iStockphoto.com/Konrad Lew

chapter template

brain scan ©istockphoto.com/Ray Roper

3 man's head ©istockphoto.com/iofoto

3 heights ©istockphoto.com/Adventure Photo

4 chromosomes ©istockphoto.com/Alex Mit

5 neuron ©istockphoto.com/ktsimage

6 young couple ©istockphoto.com/ATMarshallphotography

7 someone whose brain is being studied in a lab ©istockphoto.com/annedde

8 boy jumping ©istockphoto.com/Nicolesy Photography | Nicole S. Young

8 icon: helmet ©istockphoto.com/Li Shen Jun

8 neuron ©istockphoto.com/ktsimage

10 wires ©istockphoto.com/Take A Pix Media

11 neuron ©istockphoto.com/ktsimage

12 afferent - hand ©istockphoto.com/Joshua Blake

12 efferent - motor ©istockphoto.com/Rob Belknap

12 association - chain ©istockphoto.com/Jessica Jones Photography Ltd

12 shoulder / candle From Ciccarelli, Psychology, 2/e p. 59

13 Open Your Book - text book cover Shutterstock

13 Open Your Book - textbook background From Ciccarelli, Psychology, 1/e pp. 213-214

13 Open Your Book - open textbook From Ciccarelli, Psychology, 1/e pp. 114-115

14 neuron illustration From Ciccarelli, Psychology, 2/e p. 52

15 diagram - neuron firing From Morris/Maisto, 9/e p. 46

15 icon: wanted sign Charlie Levin, adapting wooden board image from ©istockphoto.com/andynwt

16 neuron ©istockphoto.com/ktsimage

16 synaptic vesicle illustration From Ciccarelli, Psychology, 2/e p. 54

24

16 lock icon ©istockphoto.com/KK-inc

16 key icon ©istockphoto.com/KK-inc

17 Table: Major Neurotransmitters and Their Effects From Morris/Maisto, 9/e p. 47

18 black widow spider ©istockphoto.com/[Mark Kostich] International Wildlife Photographer

18 scrap of paper ©istockphoto.com/Trevor Hunt

19 effects of cocaine illustration From Ciccarelli, Psychology, 2/e p. 57

20 rosenzweig illustrations (2) From Morris/Maisto, 9/e p. 49

22 heart icon ©istockphoto.com/twentyfourworks

22 brain & spine ©istockphoto.com/Mads Abildgaard

23 brain & spine ©istockphoto.com/Mads Abildgaard

24 brain ©istockphoto.com/Stephen Kirklys

24 icon: peer instruction Charlie Levin

25 head with brain illustration From Ciccarelli, Psychology, 2/e p. 68

26 head with brain illustration From Ciccarelli, Psychology, 2/e p. 68 (B&W closeup of previous slide image)

26 man yawning ©istockphoto.com/szefei

26 woman checking heart rate ©istockphoto.com/digital planet design

26 female gymnast ©istockphoto.com/Jiang DaoHua

27 brain ©istockphoto.com/Stephen Kirklys

28 two profiles with lobes illustration From Ciccarelli, Psychology, 2/e p. 74

29 profile with lobes illustration From Ciccarelli, Psychology, 2/e p. 74

29 icon: helmet ©istockphoto.com/Li Shen Jun

29 thinking ©istockphoto.com/Bart Coenders

29 yoga ©istockphoto.com/Carlos Alvarez

29 eye ©istockphoto.com/Bart Coenders

29 ear ©istockphoto.com/Bart Coenders

30 limbic system illustration From Morris/Maisto, 9/e p. 56

31 hemispheric specialization illustration From Morris/Maisto, 9/e p. 57

32 split-brain experiment illustrations From Morris/Maisto, 9/e p. 58

32 Get in the Game helmet ©istockphoto.com/Li Shen Jun

33 Broca's area and Wernicke's area illustration From Morris/Maisto, 9/e p. 59

34 Open Your Book - Morris book cover Shutterstock

34 Open Your Book - textbook background From Ciccarelli, Psychology, 1/e pp. 213-214

34 Open Your Book - open textbook From Ciccarelli, Psychology, 1/e pp. 114-115

35 someone whose brain is being studied in a lab ©istockphoto.com/annedde

36 illustration brain & spinal cord From Morris/Maisto, 9/e p. 62

37 ilustration shoulder & candle From Ciccarelli, Psychology, 2/e p. 59

39 heart icon ©istockphoto.com/twentyfourworks

39 man running ©istockphoto.com/Pete Saloutos

39 heartbeat Derek Borman

40 illustration of body w/ nervous system From Ciccarelli, Psychology, 2/e p. 62

40 soccer girls ©istockphoto.com/Alberto Pomares Photography

41 heart icon ©istockphoto.com/twentyfourworks

41 man running ©istockphoto.com/Pete Saloutos

42 heart icon ©istockphoto.com/twentyfourworks

42 man running ©istockphoto.com/Pete Saloutos

43 man running ©istockphoto.com/Pete Saloutos

43 sympathetic & parasympathetic illustration From Morris/Maisto, 9/e p. 64

43 icon: wanted sign Charlie Levin, adapting wooden board image from ©istockphoto.com/andynwt

44 sympathetic & parasympathetic illustration From Morris/Maisto, 9/e p. 64

44 napping woman ©istockphoto.com/Daniel Bendjy

46 man and woman endocrine system illustration From Ciccarelli, Psychology, 2/e p. 80

49 genetics illustration From Morris/Maisto, 9/e p. 69

50 eye color diagram From Morris/Maisto, 9/e p. 71

51 lab mice ©istockphoto.com/Floris Slooff

52 twins ©istockphoto.com/Chris Johnson

53 schizophrenia table From Morris/Maisto, 9/e p. 73

54 pregnancy exam ©istockphoto.com/Tamara Murray

54 laptop with breaking news ©istockphoto.com/Entienou

55 Darwin ©istockphoto.com/Steven Wynn

57 Wanted: Contemplation wanted sign Charlie Levin, adapting wooden board image from ©istockphoto.com/andynwt

57 Wanted: Contemplation cactus ©istockphoto.com/Lee Daniels

57 Wanted: Contemplation wooden board ©istockphoto.com/andynwt

57 man covering his ears ©istockphoto.com/Cat London Photography

57 guitarist ©istockphoto.com/deliormanli

58 Peer Instruction people icon Charlie Levin

58 Peer Instruction chalkboard ©istockphoto.com/Studio Araminta

59 Get in the Game helmet ©istockphoto.com/Li Shen Jun

59 Get in the Game football field ©istockphoto.com/Jamie Otterstetter

59 painter ©istockphoto.com/VikramRaghuvanshi

60 painter ©istockphoto.com/VikramRaghuvanshi

60 female police officer ©istockphoto.com/Katrina Brown

60 football player ©istockphoto.com/George Peters Design And Illustration

60 Get in the Game helmet ©istockphoto.com/Li Shen Jun

60 Get in the Game football field ©istockphoto.com/Jamie Otterstetter

61 Get in the Game helmet ©istockphoto.com/Li Shen Jun

61 Get in the Game football field ©istockphoto.com/Jamie Otterstetter

63 baseball ©istockphoto.com/Dan Thornberg

65 hammer ©istockphoto.com/Fuat Kose

66 split brain illustrations From Ciccarelli, Psychology, 1/e p. 71

67 Wanted: Contemplation wanted sign Charlie Levin, adapting wooden board image from ©istockphoto.com/andynwt

25

67 Wanted: Contemplation cactus ©istockphoto.com/Lee Daniels

67 Wanted: Contemplation wooden board ©istockphoto.com/andynwt

67 men fighting ©istockphoto.com/yulkapopkova

67 sympathetic & parasympathetic illustration From Morris/Maisto, 9/e p. 64