Health psychologists use descriptive and experimental research methods to study how psychological factors influence health. Descriptive methods include observational studies, case studies, interviews, and surveys to gather information in natural settings. Experimental methods manipulate variables to test causation and use random assignment and control groups. Epidemiological research identifies disease risk factors by relating health outcomes to characteristics of populations and their environments over time.

2. Health Psychology Methods
 Health psychologists use various research methods in
their search to learn how psychological factors affect
health.
 To answer questions regarding how people cope with
medical procedures or cancer, for example, a
psychologist might observe or ask questions of a large
sample of cancer patients.

3.  There are two major categories of research methods in
psychology:
 Descriptive and
 Experimental

4. Research
Method
Research
Setting
Data
Collection
Method
Strengths Weaknesses
Descriptive
studies
Field or
laboratory
Case studies,
surveys and
interviews,
naturalistic
observation.
In-depth
information
about one
person; often
leads to new
hypotheses;
detects naturally
occurring
relationships
among
variables.
No direct
control over
variables;
subject to bias
of observer;
single cases may
be misleading;
cannot
determine
causality;
correlation may
mask
extraneous
variables.
Experimental
studies
Usually
laboratory
Statistical
comparison of
experimental
and control
groups
High degree of
control over
independent
and dependent
variables;
random
assignment
Artificiality of
laboratory may
limit the
generalizability
of results;
certain variables
cannot be

5.  Epidemiology The scientific study of the frequency
distribution, and causes of a particular disease or other
health outcome in a population.

6. Descriptive Studies
 How a health psychologist might set about answering
the various health related questions?
 Researchers look for answers about the behavior of an
individual or a group of people as it occurs in the
home, at work, or wherever people spend their time.
 In such a study, called a Descriptive study, the
researcher observes and records the participants’
behavior in a natural setting, often forming hunches
that are subjected later to more systematic study.

7.  Several types of descriptive studies are commonly
used:
 case studies,
interviews and
surveys, and
observational studies.

8.  Case Studies:
 Psychologists study one or more individuals
extensively over a considerable period of time in order
to uncover principles that are true of people in general.
 Major advantage is it permits a researcher to gather a
much more complete analysis of the individual than
ordinarily can be obtained in studies involving larger
groups.

9.  Case studies are useful in suggesting hypotheses for
further study.
 They do have one serious disadvantage: Any given
person may be atypical, limiting the “generalizability”
of the results.
 E.g; “Darryl Kile was a professional athlete, wasn’t he?
He didn’t live as long as my grandfather, who never
exercised and was a lifelong cigar smoker”.

10.  Surveys
 Surveys examine individual attitudes and beliefs in
larger numbers and in much less depth than the case
study.
 Self-report measures, research participants are asked
to rate or describe some aspect of their own behavior,
attitudes, or beliefs.

11.  Surveys are among the most widely used research tools
in health psychology because:
o Easy to administer,
o require only a small investment of time from
participants, and
o quickly generate a great deal of useful data.

12.  E.g; chronic-pain patients may be asked to complete a
questionnaire related to their problem that sheds light
on the effectiveness of previous treatments and the
impact of their condition on their daily functioning.
 They are not necessarily accurate.
 Survey answers may change with the sequence and
wording of the questions.

13.  Another limitation of survey research is that
respondents sometimes answer questions in ways that
they would like to be perceived
 or that they believe the investigator expects.

14.  Observational Studies :
 In observational studies, the researcher observes
participants’ behavior and records relevant data.
 Observational studies may be structured or
unstructured.
 Those studies that feature structured observations
often take place in the laboratory.
 In unstructured observations, referred to as
naturalistic observation, the researcher attempts to be
as unobtrusive as possible in observing and recording
the participants’ behaviors.

15. Experimental Studies
 Although descriptive studies are useful, they cannot
tell us about the causes of the behaviors that we
observe.
 To pinpoint causal relationships, researchers conduct
experiments.
 Experiments are commonly used in health psychology
to investigate the effects of health-related behaviors
(such as exercise, diet, and so on) on an illness (such as
heart disease).

16.  Dependent and Independent variables.
 Experiments test hypotheses by systematically
manipulating (varying) one or more independent
variables (the “causes”)
 looking for changes in one or more dependent
variables (the “effects”)
 and controlling (holding constant) all other variables

17.  Experiments often involve testing the effects of several
different levels of the independent variable on
different groups.
 For example, in an experiment testing the level at
which noise (an independent variable) begins to
cause stress (the dependent variable).

18.  Random assignment: Assigning research
participants to groups by chance, thus minimizing
preexisting differences among the groups.
 Expectancy effects: A form of bias in which the
outcome of a study is influenced either by the
researcher’s expectations or by the study participants’
expectations.

19.  Double-blind study: A technique designed to
prevent observer- and participant expectancy effects in
which neither the researcher nor the participants
know the true purpose of the study or which
participants have each condition.

20. Quasi-Experiments
 A quasi-experiment is not a true experiment, however,
because it uses groups that differ from the outset on
the variable under study (the subject variable).
 No cause-and-effect conclusions can be drawn.
 Does not rely on the random assignment.
 Instead subjects are assigned to groups based on non-
random criteria.
 Subject group & Comparison group involved.

21. For example:
 Suppose that researchers wish to investigate the effect
of exercise on academic achievement.
 In a quasi-experiment, the subject variable would be
a sedentary lifestyle, with the group consisting of
students who by their own admission get little or no
exercise.
 The comparison group would be students who
exercise regularly.

22.  Subject variables commonly used in quasi-experiments
are either impossible or unethical to manipulate such
as age, gender, ethnicity, and socioeconomic status.

23. Developmental research:
A study in which a single group of
people is observed over a long span
of time.
Researchers use two basic research
techniques:
longitudinal studies
cross-sectional

25. a. Longitudinal research:
Used to track participants over
an extended period of time
(such as 5years, 10 years etc.)
People usually hesitate to
become the sample of these
studies due to the long
duration.

26.  A single group of individuals is observed over a long
span of time.
 This allows information about a person at one age to
be compared with information about the same person
at another age, revealing how this person changed over
time.

30. b. Cross sectional research:
 A study comparing representative groups of people of
various ages on a particular dependent variable.
 For instance, researchers compared six types of risky
health behaviors (the dependent variables) among 9th
- through 12th grade students in the United States.

31.  Involves limited time period and cost as compared to
the longitudinal method.
 A challenge in cross-sectional research is to make sure
that the various age groups are similar in other ways,
such as socioeconomic status, that might affect the
characteristic being investigated.

33.  Suppose that you are interested in studying age-related
changes in how people cope with stress.
 If you choose a cross-sectional approach, you might
interview a sample of, say, 25 adults at each of five ages—
for example 20, 30, 40, 50, and 60 years—and gather
information about the ways in which they handle job
stress, family quarrels, financial problems, and so forth.
 On the other hand, if you choose a longitudinal study to
explore the same span of years, you (or, more likely, the
researchers who will continue your study 40 years from
now) would interview a group of 20-year-olds today and
again when they are 30, 40, 50, and 60 years of age.

34. Epidemiological Research
 Epidemiologists measure the occurrence of
a particular health outcome in a population,
and then attempt to discover why it is
distributed as it is by relating it to specific
characteristics of people and the
environments in which they live.
 In other words (Gradually pinpointing the
cause)

35. Epidemiological Research
 Story of John Snow who knew something.
 John Snow and Story of Cholera in England
(1848).
 Laboriously recorded each death & observed
that death rate was 10 times higher in one
specific area.
 In some instances, residents on one side of a
residential street were stricken with the disease
far more often than were their neighbours on
the opposite side of the street.
 Eventually pinpointed (Polluted drinking water)

36. Epidemiological
Research
 Two water supplying companies
(Patchwork). Residents living on the
same street got their water from two
different companies.
 Two groups (Polluted water vs
unpolluted water) based on death
distribution.
 A major incident on the intersection of
Cambridge and Broad Street. (500
deaths in 10 days)
 Removal of Broad street pump
significantly reduced the death rate.

37. Epidemiological Research
 Bacterium responsible for epidemic
was discovered after 30 years.
 Main method was the keen
observation and counting the
number of deaths.
 In other words (Morbidity): The rate
of disease in a population. Such as
specific illness, injury, or disability in
a given group of people at a given
time.
 Mortality: Number of deaths due to a
specific cause, such as heart disease,
in a given group at a given time.

38. Epidemiological Research
 Incidence: (also called absolute
risk) refers to the number of new
cases of a disease, infection, or
disability, such as whooping cough,
that occur in a specific population
within a defined period of time.
 Prevalence: is defined as the total
number of diagnosed cases of a
disease or condition that exist at a
given time

39. Objectives in Epidemiological
Research
 Epidemiologists use several research
methods to obtain data on the
incidence, prevalence, and etiology
(origins) of disease.
 Three fundamental objectives:
1. Pinpoint the etiology of a particular
disease in order to generate
hypotheses.
2. Evaluate the hypotheses.
3. Test the effectiveness of specific
preventive health interventions

40. Story of Hypertension in African -
Americans
 42.5 percent suffer from
hypertension that contributes to
heart disease (Quite a lot
compared to overall US
population i.e. 25%).
One explanation:
 Salt retention mechanism

41. Story of Hypertension in African -
Americans
 Elevated levels of angiotensinogen II
that directly cause the blood vessels
to constrict hence increasing the
blood pressure.
 Pinpointed to Nigeria to Jamaica to
USA.
 Only 7 percent of those in rural
Nigeria had high blood pressure,
compared with 26 percent of black
Jamaicans and 33 percent of black
Americans.
 Other risk factors increase
significantly as well such as BMI,
poor diet, less exercise and stress.

42. Retrospective Studies
 Retrospective (looking back in
time)
 Retrospective studies (also
referred to as case-control studies)
compare a group of people who have
a certain disease or condition with a
group of people who do not.
 Identical to Quasi experimental

43. Retrospective
 Story of Kaposi’s Sarcoma & AIDS
 Mainly in gay men.
 Epidemiologists were able to pinpoint
unprotected anal sex as a common
background factor among the first men
to die from this deadly form of cancer.
This was years before the AIDS virus,
the human immunodeficiency virus
(HIV), was isolated.

44. Prospective
 Prospective studies (look forward
in time) to determine how a group of
individuals changes or how a
relationship between two or more
variables changes over time.
 Identical to Longitudinal study design.

45. Class Activity
 Get into groups randomly
 Your task is to create an experimental
design.
 Operationalize your concept
 Link it with past studies or concept you
have learnt so far (only 1 is fine)
 Define your IV and DV
 What will you control?
 How will you conduct the experiment.
 Your population of target, their gender,
SES, location, education and Why?
 You have 30 minutes to prepare and
submit