PSYC340 Lecture Notes - Lecture 2: Skeptical Movement, The Control Group, Dependent And Independent Variables
9 Jun 2018
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Unit 2: The Research Enterprise in Psychology
Briefly identify and describe the three goals of the scientific enterprise. (pp. 44-45)
Measurement and description: investigator must figure out a way to measure the phenomenon under
study. First goal of psych is to develop measurement techniques that make it possible to describe to
describe behavior clearly and precisely. understanding and prediction: scientists try to understand event
and the reason for their occurrence. Application and control:Scientists hope that the information they
gather will be of some practical value in helping to solve everyday problems.
What are the five steps in scientific investigations? (pp. 46, 48)
Formulate testable hypothesis: the first step in a scientific investigation is to translate a theory or an
intuitive idea into a testable hypothesis. Normally, hypotheses are expressed as predictions. To be
testable, scientific hypotheses must be formulated precisely and the variables under study must be
clearly defined. Researchers achieve these clear formulations by providing operational definitions of the
relevant variables. Operational definition establish precisely what is meant by each variable in the
context of the study. Select the research and design the study: The second step is to figure out how to
put the hypothesis to an empiracal test. The research method chosen depends greatly on the nature of
the question under study. Collect the data: third step is to collect date. Analyze data and draw
conclusions: researchers use statistics to analyze their data and decide whether their hypotheses have
been supported. Thus, statistics play an essential role in the scientific enterprise. Report the findings:
the final step in a scientific investigation is to write up a concise summary of the study and its findings.
They write a report and submit it to journals for publication for critical evaluation. If flaws are serious
enough, the results may be discounted or discarded. In everyday life, we often use words casually. For
eaple, e ight desrie ourseles as full of aiet, ad our listeers ill usuall get a geeral
idea of what we are talking about. This practice, however, is not precise enough for psychological
research. If we use a word like anxiety in research, we have to define it operationally, in terms of the
actions or operations we use to measure anxiety. Anxiety, for example, might be measured using
physiological measures, such as heart rate and perspiration, or it might be measured using a test in
which people rate the extent of their anxiety. The same generally goes for other variables in a
psychology experiment as well: they must be defined precisely through the operations we use to
measure them.
Describe two advantages of the scientific approach as it relates to the study of behaviour. (pp. 48-49)
Comment: The two features of a scientific approach with respect to behaviour [i] are: (a) an insistence
on clarity and precision, and (b) avoidance of errors. To avoid errors, scientists take a skeptical attitude,
which entails believing things only after they have been proven through experiments or other means of
generating data. Scientific skepticism [i] is a way to guard against accepting false data, incorrect facts,
and bogus causal relationships. However, once data, facts, and causal relationships have passed the test
of skepticism, [i] scientists can then accept these findings as fully and passionately as they formerly were
skeptical about them. Be careful not to think of scientists as being skeptical about everything. Scientists
restrict their skepticism [i] to that which has not been proven, and they accept what has been proven.
This restrictive skepticism [i] enables scientists to assemble proven facts in understanding the world.
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Define an experiment. Define and give examples of the three types of variables (independent,
dependent, and extraneous) that may be encountered in an experiment. (pp. 49, 51)
Experiment is a research method in which the investigator manipulates a variable under carefully
controlled condidtions and observes whether any changes occur in a second variable as a result. An
independent variable is a condidtion or event that an experimenter varies in order to see its impact on
another variable. It is the variable that the investigator controls or manipulates. Dependent variable is
the variable that is thought to be affected by manipulation of the independent variable. In psych, the
dependent variable is usually a measurement of some aspect of the participants behavior.
Distinguish between experimental and control groups, and explain their relationship in an experiment.
(p. 50) (See also Unit 2 (Chapter 2) Conceptual Exercises: Variables and Designs.)
Experimental group consists of the subjects who receive the some special treatment in regard to the
independent variable. The control group consists of similar subjects who do not receive the special
treatment given to the experimental group. It is crucial that the experimental and control group be
alike., expect for the treatment that they receive in regard to the independent variable.
Why is it sometimes advantageous to use only one group of subjects who serve as their own control? (p.
52) (See also Unit 2 (Chapter 2) Conceptual Exercises: Variables and Designs regarding between- and
within-subjects design.)
as their own control? (p. 50)
Comment: Although Weiten and McCann (2007) do not specifically identify them as such, two broad
types of experimental design are used in psychology: [i]
between-subjects design
within-subjects design
The between-subjects design typically involves an experimental group [i] of subjects [i] and at least one
control group [i] of subjects. [i] For example, the subjects [i] in an experimental group [i] might be given
the drug the researcher is interested in testing, while the subjects [i] in the control group [i] are given a
placebo. The researcher will then check to determine whether any significant differences exist between
the two groups of subjects. [i] The within-subjects design does not require a separate control group. [i]
In this design, one group of subjects [i] (or even a single subject) acts as their own control. Thus, the
researcher might take repeated measures of eah sujet’s respose to differet eperietal
conditions. For example, each subject might be given the placebo first, then the drug the researcher is
interested in testing, then the placebo again. This approach is known as an A-B-A design. These designs
are useful because they show the effects of a variable on an individual subject rather than on a
hpothetial aerage sujet. It is soeties adatageous to use ol group of sujets ho sere
as their own control group for 3 reasons.
1. the effects of the independent variable are evaluated by exposing this single group to different
conditions--an experimental condition and a control condition.
2. It is possible to manipulate more than independent variable in a single experiment
3. It is also possible to use more than one dependent variable in a single study.
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Document Summary
Briefly identify and describe the three goals of the scientific enterprise. (pp. Measurement and description: investigator must figure out a way to measure the phenomenon under study. First goal of psych is to develop measurement techniques that make it possible to describe to describe behavior clearly and precisely. understanding and prediction: scientists try to understand event and the reason for their occurrence. Application and control:scientists hope that the information they gather will be of some practical value in helping to solve everyday problems. What are the five steps in scientific investigations? (pp. Formulate testable hypothesis: the first step in a scientific investigation is to translate a theory or an intuitive idea into a testable hypothesis. To be testable, scientific hypotheses must be formulated precisely and the variables under study must be clearly defined. Researchers achieve these clear formulations by providing operational definitions of the relevant variables.
