General Psychology

1. BIOLOGICAL BASIS OF
BEHAVIOR
By Maria Jezza C. Ledesma

2. • We humans have innate behavioral
tendencies, just as fish have an inborn knack
for swimming and most birds are built for
flight.
• The human brain is born already programmed
for language, social interaction, and many
other possibilities.
• When the environment serves up severe
challenges, only those most genetically
prepared can compete and pass their genes
on to their offspring.

3. • Heredity and evolution influence our
physical and mental characteristics.
• Biopsychology seeks to understand the
biochemical processes behind the
behavior of all living creatures.
• In general, they want to explain how the
nervous system and its companion
communication network, the endocrine
system, cooperate to produce human
action.

4. Heredity
How does heredity
influence the development
of intelligence and
temperament?

5. • All babies are born with a kind of
prearranged pattern as a result of a process
of transmission of genetic characteristics
from the parent to the offspring called
heredity, that determine many of their
specific characteristics, especially those
affect development.

6. 1. Technically, each life begins at
conception when the father’s cell, the
sperm unites with the mother’s cell,
the egg or ovum, producing a single
cell, known as the zygote.

7. 2. The nucleus of the zygote contains forty-six
minute particles, called chromosomes (from
the Greek words meaning “colored bodies”).
Chromosomes are rope-like structures
found in the nucleus of the cell. Each
chromosome contains thousands of genes
which are the true determinants of
hereditary traits. There are genes for all
kinds of traits.

8. 3. Each chromosome in the zygote’s nucleus
carries thousands of even smaller particles
called genes. We will consider the gene the
basic unit of heredity. Composed of a
complex chemical substance,
deoxyribonucleic acid (DNA for short). The
human cell contains 46 chromosomes
arranged in 23 pairs.

10. 4. The actual carrier of hereditary information
within the genes is DNA. DNA gives special
“hereditary instructions” for the cellular
development of the organism and these
instructions are partially carried out by RNA.
The RNA involved in the process is
messenger RNA and transfer RNA.

11. Principles of Heredity
1. Principle of Chance
2. Principle of Dominance and
Recessiveness
3. Sex-Linked Traits
4. Principle of Reproduction
5. Principle of Variation

14. • Dominant - most important,
powerful, or influential.
• Recessive - A recessive gene is a
gene that can be masked by a
dominant gene. In order to have a
trait that is expressed by
a recessive gene, such as blue
eyes, you must get the gene for
blue eyes from both of your
parents.

15. Common Dominant and Recessive Traits
in Humans
• Rolling of Tongue
If you can roll the lateral edges of your
tongue together, then this means you
have inherited a dominant trait. Those
who are unable to do so are expressing
inheritance of recessive gene for
tongue rolling.

16. • Cleft Chin
People who
have a cleft
chin have
inherited a
dominant gene
and those with
smooth chin
have recessive
gene.

17. • Dimples
Have you fallen for the
cute dimples of Preity
Zinta? Well, Preity Zinta
and people all over the
world with dimples are
expressing the
dominant gene for
dimples. Whereas,
people without dimples
have recessive genes.

18. • Handedness
The gene for right-
handedness is
dominant and the
gene for left hand
is recessive. Thus,
majority of the
people have
inherited the
dominant gene
resulting in right-
handedness.

19. • Natural Curly
Hair
The gene for
naturally
curly hair is
dominant and
the gene for
straight hair
is recessive.

20. • Freckles
All those with
freckles, you have
inherited at least
one pair of
dominant gene for
freckles. Those
without freckles
have inherited two
recessive genes
for freckles.

21. • Allergies
People with allergies may have inherited
the gene for allergy from at least one of
the parent. It is seen that a parent with
allergies has a chance that one of four of
their children may develop allergy. The
chances of child inheriting allergy from a
parent is about 25% and the risk increases
if both parents have allergies.

25. Organization, Structure of
the Brain and its Parts

27. • Humans have probably recognized
the existence of a link between the
body and mind – although they
don’t always know that the brain is
the main organ of the mind.
• Even today, one might speak of
“giving one’s heart” to another
when falling in love, or “not having
the stomach” for something when
describing disgust.

28. • Today, we know that love does
not reside in the heart, nor
courage in the digestive
system. We know that
emotions, desires, and
thoughts flow from the brain.

29. Three Layers of the Brain

30. • Many psychologists would distinguish
three most important layers that
appeared in the evolutionary sequence
leading to the human brain.
– Hindbrain
– Midbrain
– Forebrain

31. Hindbrain
• Medulla
• Cerebellum
• Pons

32. Medulla Oblongata
• Location: Lower part
of the brain stem
• Function: Carries out
and regulates life
sustaining functions
such as breathing,
swallowing and heart
rate

33. Medulla Oblongata
• The medulla oblongata is a
section of the brain located in
the brainstem which is
responsible for
automatic functions like
breathing, blood pressure,
circulation and
heart functions, and
digestion. It is also the area
responsible for many reflexes
like swallowing, vomiting,
coughing, and sneezing.

34. Medulla Oblongata
• Injury to the medulla oblongata may
result in a number of sensory-related
problems. These include numbness,
paralysis, difficulty swallowing, acid
reflux, and lack of movement control.
Because the medulla controls vital
autonomic functions, such as breathing
and heart rate, damage to this area of the
brain can be fatal. Drugs and other
chemical substances can impact the
medulla's ability to function.

35. Medulla Oblongata
• An opiate overdose can be deadly
because these drugs inhibit medulla
activity and the body becomes unable to
perform vital functions. The chemicals in
anesthesia work by acting on the
medulla to decrease autonomic activity.
This results in a lower breathing rate and
heart rate, relaxation of muscles,
and loss of consciousness.​

36. Cerebellum
• Location: Lower
area of the brain,
below the pons
Function: Respon
sible for balance
and coordination
of muscles and
the body

37. Cerebellum
• The cerebellum is one of the most
identifiable parts of the brain due
to its unique shape and location. It
is extremely important for being
able to perform
everyday voluntary (done with
purpose and intent) tasks such as
walking and writing.

38. Cerebellum
• It is also essential to being able to
stay balanced and upright.
Patients who have suffered from
damaged cerebellums often
struggle with keeping their balance
and maintaining proper
muscle coordination.

39. Pons
• Location: Area of
the hindbrain that
sits directly above
the medulla
Function: Conne
cts upper and
lower parts of the
brain

40. Pons
• The Pons serves as a message
station between several areas of
the brain. It helps relay messages
from the cortex and the
cerebellum. Without the pons, the
brain would not be able to function
because messages would not be
able to be transmitted,or passed
along.

41. Pons
• It also plays a key role in sleep
and dreaming, where REM
sleep, or the sleeping state
where dreaming is most likely
to occur, has been proven to
originate here, in the pons.

42. Pons
• REM
–a kind of sleep that occurs at
intervals during the night and is
characterized by rapid eye
movements, more dreaming and
bodily movement, and faster
pulse and breathing.

43. Midbrain

44. Midbrain

45. Forebrain

47. Thalamus
• Location: Part of the
forebrain, below the
corpus callosum
• Function: Responsible
• for relaying information
from the sensory
receptors to proper areas
of the brain where it can
be processed.

48. Thalamus
• The thalamus is similar to
a doctor that diagnoses,
or identifies, a patient's
disease or sickness. It
diagnoses different
sensory information that
is being transmitted to the
brain including
auditory (relating to
hearing or sound),
visual, tactile (relating to
touch), and gustatory (rel
ating to taste) signals.

49. Thalamus
• After that, it directs the
sensory information to
the different parts and
lobes of the cortex. If
this part of the brain is
damaged, all sensory
information would not
be processed and
sensory confusion
would result.

50. Hypothalamus
• Location: Above
the pituitary gland and
below the thalamus
• Function:
• Responsible for
behaviors such as
hunger and thirst, as
well as
the maintenance of body
temperature

51. Hypothalamus
• The hypothalamus is
mainly responsibly
for motivational
behavior. It is the
reason we know
when we are hungry
or thirsty.
The hypothalamus
also helps our body
maintain a constant
temperature.

52. Hypothalamus
• This part of the brain
also controls
the pituitary gland,
which is the master
gland that controls all
the other endocrine
glands in the body.
Thus, the hypothalamus
plays a key role in
connecting the
endocrine system with
the nervous system.

54. The Limbic System
• It is not only responsible for our
emotional lives but also our higher
mental functions, such as learning and
formation of memories. The limbic
system is the reason that some
physical things such as eating seem so
pleasurable to us, and the reason why
some medical conditions, such as high
blood pressure, are caused by mental
stress.

55. The Limbic System
• Principal Structures
– Amygdala
– Hippocampus

56. Amygdala
• The amygdala is a small
almond-shaped
structure; there is one
located in each of the
left and right temporal
lobes. Known as the
emotional center of the
brain, the amygdala is
involved in evaluating
the emotional valence of
situations (e.g., happy,
sad, scary).

57. Amygdala
• It helps the brain recognize potential
threats and helps prepare the body for
fight-or-flight reactions by increasing
heart and breathing rate. The amygdala
is also responsible for learning on the
basis of reward or punishment.

58. Hippocampus
• The hippocampus is
found deep in the
temporal lobe, and
is shaped like a
seahorse. It
consists of two
horns curving back
from the amygdala.

59. Hippocampus
• Psychologists and
neuroscientists dispute the
precise role of the
hippocampus, but generally
agree that it plays an essential
role in the formation of new
memories about past
experiences. Some researchers
consider the hippocampus to be
responsible for general
declarative memory (memories
that can be explicitly verbalized,
such as memory of facts and
episodic memory).

60. Hippocampus
• Damage to the hippocampus usually results
in profound difficulties in forming new
memories (anterograde amnesia), and may
also affect access to memories formed prior
to the damage (retrograde amnesia).
Although the retrograde effect normally
extends some years prior to the brain
damage, in some cases older memories
remain intact; this leads to the idea that over
time the hippocampus becomes less
important in the storage of memory.

61. How much can our brain store?
GB..TB… or more?
• According to Paul Reber, professor of
psychology, Northwestern University, the
human brain consists of about one billion
neurons. Each neuron forms about 1,000
connections to other neurons, amounting to
more than a trillion connections. If each
neuron could only help store a single
memory, running out of space would be a
problem. You might have only a few
gigabytes of storage space, similar to the
space in an iPod or a USB flash drive.

62. How much can our brain store?
GB..TB… or more?
• Yet neurons combine so that each one helps
with many memories at a time, exponentially
increasing the brain’s memory storage
capacity to something closer to around 2.5
petabytes (or a million gigabytes). For
comparison, if your brain worked like a digital
video recorder in a television, 2.5 petabytes
would be enough to hold three million hours
of TV shows. You would have to leave the TV
running continuously for more than 300 years
to use up all that storage.

63. How much can our brain store?
GB..TB… or more?
• The human brain has always been one of the
most intriguing mysteries on
earth. Meet Steven Wiltshire, also known as
the human camera. When he was 11, he drew
a perfect aerial view of London after a
helicopter ride.

65. Cerebral Cortex (cerebrum)
• Location: Outer
most layer of the
brain
Function: Resp
onsible for
thinking and
processing
information from
the five senses

66. Cerebral Cortex (cerebrum)
• The Cerebral Cortex is
made up of tightly
packed neurons and is
the wrinkly, outermost
layer that surrounds the
brain. It is also
responsible for higher
thought processes
including speech and
decision making.

67. Cerebral Cortex (cerebrum)
• The cortex is divided
into four different lobes,
the frontal, parietal,
temporal, and occipital,
which are
each responsible for
processing different
types of sensory
information.

68. Frontal Lobe
• Location: Frontal
and upper area of
the cortex
• Function: Carries
out higher mental
processes such as
thinking,
decision making,
and planning

69. Frontal Lobe
• You use your frontal lobe nearly everyday.
You use it to make decisions, such as what
to eat or drink for breakfast in the morning,
as well as for thinking or studying for a test.
The frontal lobe is also where our personality
is formed and where we can carry out higher
mental processes such as planning. In
addition, the frontal lobe is necessary to
being able to speak fluently(without fault)
and meaningfully.

70. Parietal Lobe
• Location: Upper,
back part of the
cortex
Function: Processe
s sensory
information that had
to do with taste,
temperature, and
touch

71. Parietal Lobe
• The parietal lobe carries out some very
specific functions. As a part of the cortex, it
has a lot of responsibilities and has to be
able to process sensory information within
seconds. The parietal lobe is where
information such as taste, temperature and
touch are integrated, or processed. Humans
would not be able to feel sensations of
touch, if the parietal lobe was damaged.

72. Temporal Lobe
• Location: Bottom
middle part of cortex,
right behind the temples
• Function: Responsible
for processing auditory
information from the
ears (hearing)

73. Temporal Lobe
• The Temporal Lobe mainly revolves around hearing
and selective listening. It receives sensory
information such as sounds and speech from the
ears. It is also key to being able to comprehend, or
understand meaningful speech. In fact, we would not
be able to understand someone talking to us, if it
wasn't for the temporal lobe. This lobe is special
because it makes sense of the all the different
sounds and pitches (different types of sound) being
transmitted from the sensory receptors of the ears.

74. Occipital Lobe
• Location: Bottom,
back part of the
cortex
• Function:
Responsible for
processing visual
information from
the eyes

75. Occipital Lobe
• The occipital lobe is important to being able
to correctly understand what your eyes are
seeing. These lobes have to be very fast to
process the rapid information that our eyes
are sending. Similar to how the temporal
lobe makes sense of auditory information,
the occipital lobe makes sense of visual
information so that we are able to
understand it. If our occipital lobe
was impaired, or injured we would not be
able to correctly process visual signals, thus
visual confusion would result.