The study of the way people think and behave is called psychology. The
field of psychology has a number of sub-disciplines devoted to the study of the
different levels and contexts of human thought and behavior. Social psychology,
for example, deals with human thought and action in a social context, while
is concerned with thought and behavior at the level of
neurology. Another division of psychology, comparative psychology compares the
thought and behavior of humans with that of other species. Abnormal psychology
studies atypical thought and action.
Psychology is an interdisciplinary science. Social psychology, for
example, involves both sociology and anthropology. Abnormal psychology has much
in common with psychiatry, while physiological psychology builds on the
techniques and methods of neurology and physiology.
It is evident that psychological methods are being increasingly used in
daily events. Employment for example, in Europe more companies are subjecting
potential personnel to psychological profile
checks and psychological tests
during interviews. Even our social lives are becoming affected. People who are
seeking the right partner are using psychological techniques to establish the
emotional state of their potential partners. As psychology becomes more and more
accessible and understandable to more people, I feel that it will begin to
influence our lifestyles more.
From a personal stand point, this has been a very difficult exercise.
This is a new area for me, so I have been unable to write from a professional or
work experience perspective only from a purely academic view.
'Psychology' literally means 'study of the mind'. Psychology as a
separate discipline is usually dated from 1879 when Wundt opened the first
psychology laboratory, devoted to the analysis of conscious thought into its
, structuralism. It is understood that 'structuralism' was
founded by Wilhelm Wundt. What made this 'new' psychology different from
philosophy was the emphasis on measurement and control. The application of some
of the basic scientific method to the study of the mental process.
For psychology to become a natural science, it must confine itself to
what is observable and measurable by more than one person, namely behaviour,
Behaviourism was established. This movement was formally initiated by John
Broadus Watson in a famous paper, "Psychology as the Behaviourist Views It"
published in 1913.
At the time when behaviourism was becoming prominent in America a group
of German psychologists began to discredit the principles of structuralism and
behaviourism. They argued that it was not possible to break down psychological
processes. This theory, demonstrated that our perceptions are highly organised
and have immediate, vivid qualities that cannot be explained in terms of piecing
together basic elements. The psychologists had the opinion that our perceptions
are inherently configurational, meaning that the elements making up the
perception could not be separated from the way in which those elements were
combined as a whole. This now popular theory is known as 'Gestalt' taken from
the German word for "configuration"
The expression of the third force movement known as "humanistic
psychology" is an eclectic grouping of American psychologists who advocated
various interpretations of human personality. The term humanistic reflects the
focus on defining a human psychology with emphases on individual existence,
focusing on the role of free choice and our ability to make rational decisions
on how we live.
During the 1950s and 1960s, many psychologists began to look to the work
of computer scientists in trying to understand the more complex behaviour which,
they felt, learning theory or conditioning had oversimplified. This behaviour
was referred to by early psychologists as 'mind' or mental processes, which has
become cognition or the cognitive process. The cognitive psychologist sees the
person as an information processor and cognitive psychology , along with
artificial intelligence, linguistics, philosophy, anthropology and neuroscience
now form part of cognitive science, which emerged in the late 1970s.
How can we divide up the work that psychologists do? There is much more
under the heading of 'psychology' than the theories and principles of famous
and leading psychologists of our time. There are psychologists in all areas,
specialising in a number of fields.
Physiological psychology is concerned with the neurological and
physiological events that underlie human thought and action. Some physiological
psychologists are concerned with mapping the functions of various parts of the
brain. Others study both the transmission of electrical information in the brain
and the neurotransmitters that facilitate or inhibit such transmissions.
Physiological psychologists study the effects of drugs on human behavior.
Conditioning and learning are concerned with how experience modifies
thought and behavior. Initially devoted to the investigation of principles of
learning among all species, the field now includes specific types of learning
for different species. Other areas of interest in the field include maladaptive
learning, such as learned helplessness, and learning in traditional settings
such as in the classroom and on the job.
Cognitive psychology applies to the study of thinking, concept formation,
and problem solving. Work in this field has been much influenced and aided by
the use of computers. Computers are used to present problems and tasks to
subjects and to model the thinking and problem-solving processes. The impact of
computers on cognitive psychology is also evident in the theories used to
describe human thought. For example, such terms as short-term memory and long-
term memory parallel the two types of memory that are available on computers.
Social psychology looks into all facets of human social interaction.
Among the problems studied by social psychologists are such matters as the
development of friendship, the nature of romantic attachment, and the relative
effectiveness of cooperation and competition on achievement. In recent years
social psychology has included the study of attribution. Attribution theory
recognizes that psychological perceptions of events do not always correspond to
Abnormal psychology is the study of maladaptive behaviors. Such
behaviors range from the simple habit disorders (thumb sucking, nail biting), to
the addictions (alcohol, gambling and so on) to the most severe mental
disturbances the psychoses. Abnormal psychology investigates the causes and
dynamics of mental and behavioral disorders and tests the effectiveness of
Vocational psychology is the study of how specific personality traits
contribute to success in different vocations. In one approach the
characteristics of people already working in a specific vocation are studied. If
a personality pattern emerges, tests can then be constructed to measure the
traits and interests of people in the field. Other individuals who exhibit the
same traits and interests can be counseled to consider the field as a possible
vocational choice. Vocational psychologists also look for traits and aptitudes
that contribute to success in a vocation.
Industrial psychology concerns the physical and psychological conditions
of the workplace and how these factors contribute to an efficient work
environment. Industrial psychologists are also concerned about the design of
manufactured products. Some industrial psychologists, for example, are involved
in the design of such items as dashboards, which are used in airplanes and
automobiles. Their aim is to apply a knowledge of human capabilities and
limitations to the design of instrumentation that is to be used by humans.
Business psychology, a relatively recent branch of psychology, is the
study of the effectiveness of interpersonal relations in the workplace. Some
business psychologists set up training workshops to improve executives'
management skills. They also evaluate prospective job applicants and evaluate
individuals being considered for promotion. They employ the full range of
psychological tests as well as interview procedures. Instruments are often
designed for specific types of evaluations. Experimental psychology
encompasses many different fields of psychology that employ experimental
procedures. Traditionally it has been regarded as the study of the basic sensory
mechanisms: vision, hearing, taste, touch, and smell. The classical problems of
experimental psychology are determining reaction times and reaction thresholds
(the amount of stimulation needed to produce a response for any given sense) as
well as developing psychological scales for physical stimuli, called
psychophysics. Hot and cold, fo r example, are psychological scalings of
temperature stimuli for which such physical measures as degrees Fahrenheit
provide only physical units. Much experimental psychology today is closely tied
with physiological psychology.
Animal psychology includes several different disciplines. One is
comparative psychology, which explores animal behavior in comparison to human
behavior. Comparative psychologists, for example, might present different
species with comparable tasks, to see how their performances differ. Animal
psychologists also study animals to gain insight into human behavior. For
example, the effects of drugs and tobacco on animals are observed to determine
the effects these substances have on humans.
Developmental psychology is concerned with the growth and development of
individuals. Once concerned primarily with the growth and development of
children, the field has expanded to include the growth and development of
individuals throughout their lives. Developmental psychologists explore changes
associated with mental, social, and emotional development. They also look at the
evolution of friendships and parent-child relationships. How children learn both
in and outside school is another focus of developmental research.
Clinical psychology has undergone rapid growth in recent years and is
now the largest sub-discipline within psychology. Clinical psychologists work in
hospitals, in clinics, and in private practice. Their main concerns are the
diagnoses and treatment of learning and emotional problems. Many conduct
psychological research along with their applied work.
The goal of psychology must be to further understand behaviour. This has
to be done through theories. Good psychological theories generate hypotheses
about how human behaviour should respond to given conditions. Psychology has to
develop and comprehend the behavioural attitude of not only humans but animals,
and establish more relevant theories as the science of psychology advances.
Methods of Psychology.
Psychologists use a number of research methods to study behaviour. These
include surveys, observation, case studies, correlation method and experimental
Performing a survey is one of the most widely used methods of
psychological research. Representative groups are questioned either face to face
or by being given formal questionnaires to complete. There are limitations to
surveys. There can easily be a bias within the groups questioned. For example,
gender, social or economic differences etc. This can give a limited insight as
to the true attitude of the group surveyed. It can also make considerable
difference as to how the questions are composed. Any question can be written
with a critical or creative style which can determine the way the person taking
part in the survey will answer. The only way to take a poll or survey is to
guarantee that the individuals surveyed (a sample) will be representative of the
whole group you are interested in. In a random sample, every individual in the
population has an equal chance to be in the sample.
Observational research methods can either be in a controlled environment
or subjects can be observed in their normal day to day habitat, known as
naturalistic observation. The most critical feature of naturalistic observation
is that 'the act of observing someone must not interfere with how the person
behaves'. When people know they are being watched , they are likely to try and
look as good as they can. The advantage of naturalistic observations is that
they are made under real life conditions. The main disadvantage is that we can
seldom say with certainty why people behaved as they did because we do not have
any control over the circumstances in which they were behaving.
Most data-gathering procedures in psychology collect a limited amount of
information from a large number of people, the aim of a case study is to obtain
large amounts of information about an individual or small group. Detail of this
kind can help the psychologist understand complex relationships and behavioral
patterns. Among the disadvantages of case studies is the potential for observer
bias and the lack of proper sampling opportunities.
A list of facts and figures of the kind that may be obtained from any of
the previous research methods can only provide a limited insight into the nature
of behaviour. A useful strategy is to look for relationships among the various
measures obtained. Studies with this purpose are described as correlational.
Correlational studies may use a number of different research methods to obtain
the data. The distinctive feature of a correlational study is not the method
used to gather the data but the questions the data is designed to answer.
The difficulty with correlational studies is not that they fail to
suggest causal relations but that they suggest too many. The experiment is the
only method by which science can establish causal relations. In experimental
research the conditions under which observations are made are arranged so the
number of possible causes can be controlled and specified. All experiments have
one or more independent and dependent variables. The independent variable is the
set of conditions established by the experiment. The dependent variable is that
aspect of the subjects' behaviour measured by the experimenter and which could
possibly be influenced by the independent variable. Naturally the limitation of
any experimental research is the artificial surroundings in which they are
Psychology makes extensive use of statistics. These methods have two
broad functions in the analysis of data: descriptive and inferential. The aim of
descriptive methods is to provide a summary of data so that important features
are more readily apparent. Inferential methods are used to evaluate the extent
to which data supports a hypotheses or can be generalised beyond the particular
study being analysed.
The controlling influence over all of these research methods is of
course ethics. Ethics considerations arise with both human and animal subjects.
To help researchers, as well as safeguard the welfare of the subjects, ethical
guidelines exist in many countries.
THE NERVOUS SYSTEM.
The nervous system of humans and other vertebrates consists of two major
parts: the central nervous system (CNS) and the peripheral nervous system (PNS)
The CNS consists of the brain and the spinal cord. It occupies the
commanding position in the nervous system, as it coordinates and integrates all
The PNS, which transmits messages to and from the CNS. has two
divisions: somatic and autonomic. Autonomic nerves are motor nerves only. They
regulate a great variety of bodily functions.
The very elaborate cerebral cortex is layered sheet some 2.5mm thick of
literally billions of nerve cells that go over and around the brain. It covers
the upper and outer portions of the brain called the cerebrum. This is why it
is called the cerebral cortex. The cortex is wrinkled and folded. This
convoluting greatly enlarges the surface area available, compared to a similarly
sized smooth cortex.
The cerebrum is divided down the middle from front to back into two
halves: the right and the left cerebral hemispheres. Each hemisphere controls
the activities of the opposite side of the body that is, the left cerebral
hemisphere controls the right side of the body and the right hemisphere controls
the left side. Although in many ways the two hemispheres are mirror images of
one another, there are functional distinctions between them. In most people, the
areas that control the development and use of language are located in the left
hemisphere, while areas that govern three-dimensional visualization and musical
and artistic creation are located in the right hemisphere.
Each hemisphere of the cerebrum is divided into four sections: the
frontal, parietal (top rear), temporal (lower), and occipital (rear) lobes. The
back part of the frontal lobe contains areas that govern movement of the
opposite side of the body. Damage to this region results in paralysis. In front
of this region is an area of the frontal lobe called the premotor cortex, where
complex movements are controlled. Still farther forward is the prefrontal cortex,
which exerts an inhibitory control over actions. Such distinctly human abilities
as foreseeing the consequences of an action, exercising self-restraint, and
developing moral and ethical standards depend on the normal functioning of the
prefrontal cortex. The parietal lobe, the part of the hemisphere that lies
behind the frontal lobe, contains the primary sensory cortex the part of the
brain. It receives sensory information from the opposite side of the body. Below
the frontal and parietal lobes is the temporal lobe, which is involved with
heari ng and memory. Behind the temporal lobe is the occipital lobe, the visual
center of the brain. Here the signals that come to the brain from the eyes are
put through very complex transformations in a process of analysis and
Cranial nerves are a group of 12 pairs of sensory, motor, or mixed
(having separate sensory and motor fibers) nerves that connect with the brain
stem and the lower parts of the brain.
The Endocrine System.
Endocrine glands secrete onto adjacent tissue where the hormone is
picked up by the blood, lymph system, or nerve cells and transported to the
target organ. The adrenals, thyroid, parathyroid, pituitary, hypothalamus,
pineal, and ovary are endocrine glands. The secretions of endocrine glands are
called hormones. Mixed exocrine and endocrine glands, which secrete in both ways,
include the liver, testes, and pancreas. Endocrine glands release extremely
small amounts because hormones are powerful substances. The activities of the
endocrine glands form one of the most complex systems in the body. Although each
gland has its own unique function, the glands are interdependent, and the
function of one depends on the activity of another. The hypothalamus produces
several hormones, including those that regulate pituitary activity. The
pituitary produces its own hormones that regulate growth and stimulate other
endocrine glands. The adrenals, thyroid, testes, and ovaries are dependent upon
pituitary stimulat ion. The hormones these glands produce govern metabolism,
blood pressure, water and mineral balance, and reproductive functions, and they
help defend against injury. The term hormone is derived from a Greek word
meaning 'stir up'.
Drugs Affecting Behaviour.
Many kinds of drugs are prescribed for anxiety, sleeping and nervous
disorders. Several types of sedative drugs induce sleep and cause intoxication.
These drugs although prescribed for sleep disorders and anxiety problems, can
also cause physical and psychological dependence. These include ethyl alcohol,
barbiturates, methaqualone, and many others.
There are of course everyday drugs that are consumed in enormous
quantities by millions of people. Caffeine, nicotine and alcohol are used daily
by a large number of people, to the extent where they could be classed as
addictive. Alcohol addiction is by far one of the most common addictions
globally. While there appears to be little evidence that using alcohol in
moderation does any damage, but excessive drinking is a major problem in many
countries causing many man hours of lost work, social and domestic violence
problems. Repeated heavy drinking can cause serious medical problems, liver
damage and irreversible brain damage in some cases.
The term sensation refers to the process of receiving information in the
form of energy (light, heat, sound etc.) from the world outside and sorting it
out into the proper sense - vision, touch, hearing. Once that information has
been received, we interpret it and arrive at an understanding of what it means,
a process referred to as perception. Sensation and perception make up an
extensive information gathering system.
Each sense has it's own receptors that constantly monitor our
environment. All sensory systems have certain characteristics: The sensory
system must be selective, which means that only certain types of incoming
information are processed. For example, we have more than one kind of receiver
for touch. One which responds to changes in temperature and one which responds
to damaged cells. The sensory system must have an adjustable speed. Nerve fibres
to the ear respond in less than a thousandth of a second because sudden noise
does not require analysis, as it does a speedy response. However, the visual
system will respond quickly to a blur as something comes towards us, a
potential danger, yet it will take it's time when analyzing a complex scene.
The system must also be sensitive, but not too much. If our ears were too
sensitive we would hear blood running through artery at the base of the ear.
Sensory measurement must be reliable. Reliability comes from comparing incoming
stimulus with the conditions around us.
The optic nerve delivers its impulses to a special area of the brain
called the visual center . This is where people "see" objects in the sense of
recognizing and reacting to what their eyes look at. In other words, seeing
always involves the brain's visual center. Here sensation turns into perception.
The brain must learn by experience to analyze correctly the impulses it
receives from the eyes. For instance, the lens system of the eye, like that of a
camera, transmits its light pattern upside down. The brain has to learn that the
impulses received from the upper part of the retina represent the lower part of
the object sighted and vice versa.
In the brain also are located the centers that control all the eye's
muscular movements, such as the opening and closing of the iris, the focusing of
the main lens, and the movement of the eyeball. The eyeball's movement is
voluntary. Other eye adjustments are reflexes. Most individuals use both eyes
to see an object. This type of sensory perception is known as binocular vision.
Thus two images of the object are formed one on the retina of each eye. Impulses
from both images are sent to the brain. Through experience these impulses are
interpreted as two views of the same object. Because the eyes are about 2
inches apart from pupil to pupil and therefore are looking at the object from
different angles, the two views are not exactly alike. This is known as the
stereoscopic effect. If the object is far away, the difference between the
images is slight. If it is a few inches away, the difference is very great. The
brain makes good use of this phenomenon. It learns to judge the distance of an
object b y the degree of difference between the images it receives from the two
eyes. In the same way the brain perceives what is called perspective.
The retina is a soft, transparent layer of nervous tissue made up of
millions of light receptors. The retina is connected to the brain by the optic
nerve. All of the structures needed to focus light onto the retina and to
nourish it are housed in the eye, which is primarily a supporting shell for the
retina. When light enters the eye it passes through the lens and focuses an
image onto the retina. The retina has several layers, one of which contains
special cells named for their shapes rods and cones. Light-sensitive chemicals
in the rods and cones react to specific wavelengths of light and trigger nerve
impulses. These impulses are carried through the optic nerve to the visual
center in the brain. Here they are interpreted, and sight occurs. Light must
pass through the covering layers of the retina to reach the layer of rods and
cones. There are about 75 to 150 million rods and about 7 million cones in the
human retina. Rods do not detect lines, points, or color. They perceive only
light and dark
tones in an image. The sensitive rods can distinguish outlines or silhouettes
of objects in almost complete darkness. They make it possible for people to see
in darkness or at night. Cones are the keenest of the retina's receptor cells.
In hearing the basic energy form is sound waves. Sound waves form at
various speeds, or frequencies. The frequency of any given tone is measured in
terms of the number of cycles per second. Sound travels slowly compared to light
at anything from 20-20,000 cycles per second. The sounds we hear have three
basic characteristics. Pitch, which is the frequency of the sound. Timbre,
determines the tonal quality . The loudness or intensity of the sound wave is
measured in decibels. The human ear can pick up sounds just above '0' decibels,
otherwise there would be complete silence.
Decibels Noise Threshold
40 Quiet office Normal
60 Normal conservation Normal
75 Road Traffic Noisy
100 Subway Train Potential Damage
130 Rock Concert Human Pain Threshold
140 Aircraft Taking-off Human Pain Threshold
The Structure of the Ear.
The ear has three separate sections the outer ear, the middle ear, and
the inner ear. Each section performs a specific function, related to either
hearing or balance. The three parts of the outer ear are the auricle (also
called the pinna), the external auditory meatus (or ear canal), and the tympanic
membrane (or eardrum). The pinna collects sound waves from the air. It funnels
them into a tube, the external auditory meatus. This is a curved corridor that
leads to the tympanic membrane. The eardrum separates the external ear from the
middle ear. The middle ear is an irregular-shaped, air-filled space. A link of
three tiny bones, the ossicles, spans the middle ear. When sound waves strike
the outer surface of the eardrum, it vibrates. These vibrations are mechanically
transmitted through the middle ear by the ossicles, to the opening. This opening
is the round window. Like the eardrum, the round window's membrane transmits
vibrations. It directs vibrations into the inner ear, where they enter a f luid
that fills a structure called the cochlea. This is a coiled tube that resembles
a snail's shell. Within the cochlea is housed the true mechanism of hearing,
called the organ of Corti. It contains tiny hair-like nerve endings anchored in
a basilar membrane, which extends throughout the cochlea. The unattached tips of
these nerve endings are in contact with an overhanging membrane, called the
tectorial membrane. When vibrations pass into the inner ear, they cause waves to
form in the cochlear fluid. Receptor nerve cells in the organ of Corti are
highly sensitive to these waves. Other specialized nerve cells send the
electrochemical impulses produced by the wave motion into the cochlear branch of
the acoustic nerve. This nerve carries the impulses to the brain, where sound is
It is widely accepted that there are four basic taste qualities, salty,
sour, sweet and bitter. It was originally thought that there was a sensory path
for each of these tastes. However it appears that there is a pattern of
activation in a number of different fibres providing the required sensory input
to the brain to distinguish these different tastes. The papillae on the surface
of the tongue are the receptors for these taste sensations.
Deciphering the sensory information for the sense of smell is not
dissimilar to that of taste. In the olfactory area the nerve endings grow
through the mucous membrane which act as receptors to determine odors present in
the air we breathe.
The skin or cutaneous sense has some 5 million sensors of at least 7
types throughout the human body. The three major types are Meissner's corpuscles
which sense touch. The Pacinian corpuscle's which determine movement and
vibration and the Krause end bulbs which sense changes in temperature.
Equilibrium and Proprioception.
Proprioception (kinesthesia), establishes the position of limbs and
underlies the ability to assume and maintain posture, to move about in the
environment, to manipulate objects and to be coordinated. These senses did not
figure prominently in the traditional account of senses because they have no
external sources of adequate stimulation. They do have identifiable and
understood sensory receptors. Both play an important role in maintaining posture
Perception is the primary process by which we obtain knowledge about the
world. It involves the activity of our senses in responding to external
stimulation. Perception is a skill or set of skills, not simply the passive
reception of external stimulation. The process of structuring these stimuli into
objects we can perceive is called perceptual organisation. There are a number
of principles to perceptual organisation.
Figure and Ground.
Gestalt psychologists identified the tendency to differentiate between
figure and ground. The figure being the part of an image which we notice
prominently, opposed to the background, the ground. This theory not only applies
to visual items, but