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Psychological Methods

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Presentation on theme: "Psychological Methods"— Presentation transcript:

1 Psychological Methods
Chapter 2 Psychological Methods

2 Psychologists and scientists use the same general procedures:
forming a research question forming a hypothesis testing the hypothesis analyzing the results drawing conclusions

3 For the findings of a study to be confirmed, the study must be replicated to prove that it was not just a random occurrence. Replications usually lead to new research questions. Once new questions are asked, the process begins all over again.

4 Methods used to test hypotheses:
survey method – People are asked to respond to a series of questions about a particular subject, either written or orally. various observational methods – We may use personal observations as a starting point, but once investigation begins, we must use more careful methods of observation.

5 experimental methods – Researchers use this to answer questions about cause and effect.
Before conducting a study, researchers must consider what group or groups of people they wish to examine and how respondents will be selected.

6 To accurately predict an outcome, it is necessary to study a group that represents the target population. A sample is usually chosen. A sample should be as similar to the target population as possible. In a random sample, individuals are selected from the target population and each member has an equal chance of being chosen. In a stratified sample, subgroups in the population are represented proportionally in the sample.

7 Researchers often have little control over who responds to surveys or participates in research studies. Volunteer bias must be taken into account.

THE TESTING METHOD - Psychological tests help us learn about human behavior. These include intelligence tests, aptitude tests, vocational interest inventories, and personality tests.

9 THE CASE STUDY METHOD – A case study is an in-depth investigation of an individual or a small group.
What is learned is used to generalize broader principles that apply to the larger population.

10 LONGITUDINAL METHOD – Researchers select a group of participants over a period of time, often years or decades. They are able to observe ways in which individuals change over time. Time-consuming, expensive, risky.

11 CROSS-SECTIONAL METHOD – Instead of following a set of individuals over a number of years, researchers select a sample that includes people of different ages. They compare behavior of participants in different age groups. Make generalizations.

12 NATURALISTIC-OBSERVATION METHOD – (Field study) Observe other people or animals in their natural habitats. LABORATORY-OBSERVATION METHOD –It is more useful sometimes for a psychologist to observe behavior in a lab rather than in the field. Lab is any place that provides the opportunity for observation or experimentation.

13 Once observations are made, they must be analyzed and interpreted.
One method used is correlation. This is a measure of how closely one thing is related to another. The stronger the correlation, the more closely related.

14 Positive correlation – as one goes up, so does the other
Positive correlation – as one goes up, so does the other. Ex: people with need to achieve generally earn more money. Negative correlation – as one goes up, the other goes down. Ex: when stress increases, health usually decreases.

15 Correlation describes relationship. It does not reveal cause/effect
Correlation describes relationship. It does not reveal cause/effect. Two things can be related, but not cause the other. Ex: students who make good grades usually participate in extracurricular activities, but earning high grades does not cause the participation.

16 CARROTS: Hidden terror in the produce department at your neighborhood grocery  
Everyone who ate carrots in 1920, if they are still alive, has severely wrinkled skin!!! Everyone who ate carrots in 1865 is now dead!!! 45 of yr olds arrested in Raleigh for juvenile delinquency had eaten carrots in the 2 weeks prior to their arrest !!!

17 The formula to compute a correlation coefficient is:
r = [n(åxy) – (åx)(åy)] / {[n(åx2) – (åx)2][n(åy2) – (åy)2]}0.5   Where n is the number of data pairs, x is the independent variable and y the dependent variable. Don’t freak out! You DON’T have to learn this!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!


19 Experiments contain variables (factors that can vary or change).
1. Independent variable – the factor that researchers manipulate so that they can determine its effect. 2. Dependent variable – depends on the independent variable.

20 Ideal experiments are controlled experiments
Ideal experiments are controlled experiments. That means they use experimental and control groups. Experimental groups receive the treatment, control groups do not. All other conditions in the experiment should be held constant. Participants should be randomly assigned to groups.

21 In research studies, our expectations affect what happens to us – power of suggestion.
One way that researchers can avoid the influence of expectations is by conducting a blind study where participants are unaware of the treatment they are receiving.

22 In a single-blind study participants do not whether they are receiving the treatment or not.
A study in which both participants and experimenters are unaware of who has obtained the treatment is called a double-blind study. Participants assigned randomly.

23 Psychologists follow ethical standards to:
promote the dignity of the individual foster human welfare maintain scientific integrity

24 APA has established specific guidelines
APA has established specific guidelines. They include two important principles – confidentiality and informed consent. Confidentiality – Records are private. This is due to respect and the fact that more accurate information will be revealed if participants know it is confidential.

25 Informed consent – people agree to participate in a research study only after they have been given a general overview of the research and have been given the choice of whether or not to participate. Deception – Some experiments cannot be run without deceiving people. (Placebo, drug studies)

26 The APA says psychologists may use deception only under specified conditions:
when they believe that the benefits of the research outweigh its potential harm. When they believe that the individuals might have been willing to participate if they had understood the benefits of the research.

27 When participants receive an explanation of the study after it has occurred.
Sometimes animals are used because the study cannot be carried out on people due to ethical reasons.

28 Another area in which psychologists follow strict rules about ethics is in how they produce and present their data. Researchers must be as objective as possible in planning their study, in collecting their data, and in analyzing their data.

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