Research methods in psychology
Third edition
Evaluating a world of information
Inleiding Methodenleer
Soraya Meulmeester
, Chapter 1
Psychology is a way of thinking
Like other scientists, psychologists are empiricists. Being an empiricist means basing one’s
conclusions on systematic observations. Psychologists do not simply think intuitively about behavior,
cognition, and emotion; they know what they know because they have conducted studies on people
and animals acting in their natural environments or in specially designed situations.
Research producers, research consumers
Why the Consumer Role Is Important
Clinical psychologists, social workers, and family therapists must read research to know which
therapies are the most effective. In fact, licensure in these helping professions requires knowing the
research behind evidence-based treatments—that is, therapies that are supported by research.
How scientists approach their work
The rest of this chapter will explain the fundamental ways psychologists approach their work. First,
they act as empiricists in their investigations, meaning that they systematically observe the world.
Second, they test theories through research and, in turn, revise their theories based on the resulting
data. Third, they take an empirical approach to both applied research, which directly targets real-
world problems, and basic research, which is intended to contribute to the general body of
knowledge. Fourth, they go further: Once they have discovered an effect, scientists plan further
research to test why, when, or for whom an effect works. Fifth, psychologists make their work public:
They submit their results to journals for review and respond to the opinions of other scientists.
Another aspect of making work public involves sharing findings of psychological research with the
popular media, who may or may not get the story right.
Scientists Are Empiricists
Empiricists do not base conclusions on intuition, on casual observations of their own experience, or
on what other people say. Empiricism, also referred to as the empirical method or empirical
research, involves using evidence from the senses (sight, hearing, touch) or from instruments that
assist the senses (such as thermometers, timers, photographs, weight scales, and questionnaires) as
the basis for conclusions.
Scientists Test Theories: The Theory-Data Cycle
One theory, referred to as the cupboard theory of mother-infant attachment, is that a mother is
valuable to a baby mammal because she is a source of food. The baby animal gets hungry, gets food
from the mother by nursing, and experiences a pleasant feeling (reduced hunger). Over time, the
sight of the mother is associated with pleasure. In other words, the mother acquires positive value
for the baby because she is the “cupboard” from which food comes.
An alternative theory, proposed by psychologist Harry Harlow (1958), is that hunger has little to do
with why a baby monkey likes to cling to the warm, fuzzy fur of its mother. Instead, babies are
attached to their mothers because of the comfort of cozy touch. This is the contact comfort theory.
In the natural world, a mother provides both food and contact comfort at once, so when the baby
clings to her, it is impossible to tell why. To test the alternative theories, Harlow had to separate the
Soraya Meulmeester
,two influences—food and contact comfort. The only way he could do so was to create “mothers” of
his own. He built two monkey foster “mothers”—the only mothers his lab-reared baby monkeys ever
had. One of the mothers was made of bare wire mesh with a bottle of milk built in. This wire mother
offered food, but not comfort. The other mother was covered with fuzzy terrycloth and was warmed
by a lightbulb suspended inside, but she had no milk. This cloth mother offered comfort, but not
food.
When Harlow put the baby monkeys in the cages with the two mothers, the evidence in favor of the
contact comfort theory was overwhelming. Harlow’s data showed that the little monkeys would cling
to the cloth mother for 12–18 hours a day.
A theory is a set of statements that describes general principles about how variables relate to one
another. For example, Harlow’s theory, which he developed in
light of extensive observations of primate babies and mothers,
was about the overwhelming importance of bodily contact (as
opposed to simple nourishment) in forming attachments.
Contact comfort, not food, was the primary basis for a baby’s
attachment to its mother.
The theory not only led to the questions; it also led to specific
hypotheses about the answers. A hypothesis, or prediction, is
the specific outcome the researcher expects to observe in a
study if the theory is accurate.
Data are a set of observations.
In scientific practice, some theories are better than others. The best theories are supported by data
from studies, are falsifiable, and are parsimonious.
Good Theories Are Supported by Data. The most important feature of a scientific theory is that it is
supported by data from research studies.
Good Theories Are Falsifiable. A second important feature of a good scientific theory is falsifiability.
A theory must lead to hypotheses that, when tested, could actually fail to support the theory.
Harlow’s theory was falsifiable: If the monkeys had spent more time on the wire mother than the
cloth mother, the contact-comfort theory would have been shown to be incorrect.
Good Theories Have Parsimony. A third important feature of a good scientific theory is that it
exhibits parsimony. Theories are supposed to be simple. If two theories explain the data equally well,
most scientists will opt for the simpler, more parsimonious theory.
The word prove is not used in science. Researchers never say they have proved their theories. At
most, they will say that some data support or are consistent with a theory, or they might say that
some data are inconsistent with or complicate a theory. But no single confirming finding can prove a
theory.
Rather than thinking of a theory as proved or disproved by a single study, scientists evaluate their
theories based on the weight of the evidence, for and against.
Scientists Tackle Applied and Basic Problems
The empirical method can be used for both applied and basic research questions. Applied research is
done with a practical problem in mind; the researchers conduct their work in a particular real-world
Soraya Meulmeester
, context. An applied research study might ask, for example, if a school district’s new method of
teaching language arts is working better than the former one. It might test the efficacy of a treatment
for depression in a sample of trauma survivors.
Basic research, in contrast, is not intended to address a specific, practical problem; the goal is to
enhance the general body of knowledge. Basic researchers might want to understand the structure
of the visual system, the capacity of human memory, etc.
Translational research is the use of lessons from basic research to develop and test applications to
health care, psychotherapy, or other forms of treatment and intervention. Translational research
represents a dynamic bridge from basic to applied research. For example, basic research on the
biochemistry of cell membranes might be translated into a new drug for schizophrenia.
Scientists Make It Public: The Publication Process
When scientists want to tell the scientific world about the results of their research, they write a
paper and submit it to a scientific journal. Like magazines, journals usually come out every month
and contain articles written by various qualified contributors. But unlike popular newsstand
magazines, the articles in a scientific journal are peer-reviewed.
Soraya Meulmeester
Third edition
Evaluating a world of information
Inleiding Methodenleer
Soraya Meulmeester
, Chapter 1
Psychology is a way of thinking
Like other scientists, psychologists are empiricists. Being an empiricist means basing one’s
conclusions on systematic observations. Psychologists do not simply think intuitively about behavior,
cognition, and emotion; they know what they know because they have conducted studies on people
and animals acting in their natural environments or in specially designed situations.
Research producers, research consumers
Why the Consumer Role Is Important
Clinical psychologists, social workers, and family therapists must read research to know which
therapies are the most effective. In fact, licensure in these helping professions requires knowing the
research behind evidence-based treatments—that is, therapies that are supported by research.
How scientists approach their work
The rest of this chapter will explain the fundamental ways psychologists approach their work. First,
they act as empiricists in their investigations, meaning that they systematically observe the world.
Second, they test theories through research and, in turn, revise their theories based on the resulting
data. Third, they take an empirical approach to both applied research, which directly targets real-
world problems, and basic research, which is intended to contribute to the general body of
knowledge. Fourth, they go further: Once they have discovered an effect, scientists plan further
research to test why, when, or for whom an effect works. Fifth, psychologists make their work public:
They submit their results to journals for review and respond to the opinions of other scientists.
Another aspect of making work public involves sharing findings of psychological research with the
popular media, who may or may not get the story right.
Scientists Are Empiricists
Empiricists do not base conclusions on intuition, on casual observations of their own experience, or
on what other people say. Empiricism, also referred to as the empirical method or empirical
research, involves using evidence from the senses (sight, hearing, touch) or from instruments that
assist the senses (such as thermometers, timers, photographs, weight scales, and questionnaires) as
the basis for conclusions.
Scientists Test Theories: The Theory-Data Cycle
One theory, referred to as the cupboard theory of mother-infant attachment, is that a mother is
valuable to a baby mammal because she is a source of food. The baby animal gets hungry, gets food
from the mother by nursing, and experiences a pleasant feeling (reduced hunger). Over time, the
sight of the mother is associated with pleasure. In other words, the mother acquires positive value
for the baby because she is the “cupboard” from which food comes.
An alternative theory, proposed by psychologist Harry Harlow (1958), is that hunger has little to do
with why a baby monkey likes to cling to the warm, fuzzy fur of its mother. Instead, babies are
attached to their mothers because of the comfort of cozy touch. This is the contact comfort theory.
In the natural world, a mother provides both food and contact comfort at once, so when the baby
clings to her, it is impossible to tell why. To test the alternative theories, Harlow had to separate the
Soraya Meulmeester
,two influences—food and contact comfort. The only way he could do so was to create “mothers” of
his own. He built two monkey foster “mothers”—the only mothers his lab-reared baby monkeys ever
had. One of the mothers was made of bare wire mesh with a bottle of milk built in. This wire mother
offered food, but not comfort. The other mother was covered with fuzzy terrycloth and was warmed
by a lightbulb suspended inside, but she had no milk. This cloth mother offered comfort, but not
food.
When Harlow put the baby monkeys in the cages with the two mothers, the evidence in favor of the
contact comfort theory was overwhelming. Harlow’s data showed that the little monkeys would cling
to the cloth mother for 12–18 hours a day.
A theory is a set of statements that describes general principles about how variables relate to one
another. For example, Harlow’s theory, which he developed in
light of extensive observations of primate babies and mothers,
was about the overwhelming importance of bodily contact (as
opposed to simple nourishment) in forming attachments.
Contact comfort, not food, was the primary basis for a baby’s
attachment to its mother.
The theory not only led to the questions; it also led to specific
hypotheses about the answers. A hypothesis, or prediction, is
the specific outcome the researcher expects to observe in a
study if the theory is accurate.
Data are a set of observations.
In scientific practice, some theories are better than others. The best theories are supported by data
from studies, are falsifiable, and are parsimonious.
Good Theories Are Supported by Data. The most important feature of a scientific theory is that it is
supported by data from research studies.
Good Theories Are Falsifiable. A second important feature of a good scientific theory is falsifiability.
A theory must lead to hypotheses that, when tested, could actually fail to support the theory.
Harlow’s theory was falsifiable: If the monkeys had spent more time on the wire mother than the
cloth mother, the contact-comfort theory would have been shown to be incorrect.
Good Theories Have Parsimony. A third important feature of a good scientific theory is that it
exhibits parsimony. Theories are supposed to be simple. If two theories explain the data equally well,
most scientists will opt for the simpler, more parsimonious theory.
The word prove is not used in science. Researchers never say they have proved their theories. At
most, they will say that some data support or are consistent with a theory, or they might say that
some data are inconsistent with or complicate a theory. But no single confirming finding can prove a
theory.
Rather than thinking of a theory as proved or disproved by a single study, scientists evaluate their
theories based on the weight of the evidence, for and against.
Scientists Tackle Applied and Basic Problems
The empirical method can be used for both applied and basic research questions. Applied research is
done with a practical problem in mind; the researchers conduct their work in a particular real-world
Soraya Meulmeester
, context. An applied research study might ask, for example, if a school district’s new method of
teaching language arts is working better than the former one. It might test the efficacy of a treatment
for depression in a sample of trauma survivors.
Basic research, in contrast, is not intended to address a specific, practical problem; the goal is to
enhance the general body of knowledge. Basic researchers might want to understand the structure
of the visual system, the capacity of human memory, etc.
Translational research is the use of lessons from basic research to develop and test applications to
health care, psychotherapy, or other forms of treatment and intervention. Translational research
represents a dynamic bridge from basic to applied research. For example, basic research on the
biochemistry of cell membranes might be translated into a new drug for schizophrenia.
Scientists Make It Public: The Publication Process
When scientists want to tell the scientific world about the results of their research, they write a
paper and submit it to a scientific journal. Like magazines, journals usually come out every month
and contain articles written by various qualified contributors. But unlike popular newsstand
magazines, the articles in a scientific journal are peer-reviewed.
Soraya Meulmeester
