2.2—scientific research designs

Question 1

2.2 Learning Objectives

Answer 1

• know the key terminology related to research designs.
• understand what it means when variables are positively or negatively correlated.
  
  • positively correlated variables have a direct relationship, i.e. increase/decrease with one another.
  • negatively correlated variables have an inverse relationship, i.e. as one increases, the other decreases, or vice versa.
• understand how experiments help demonstrate cause-and-effect relationships.
  
  • at the beginning of an experiment, two or more groups are randomly assigned.
  • then, researchers manipulate an independent variable.
  • at the end, if one group turns out to the different, that difference is most likely due to the effects of the independent variable.
• apply the terms and concepts of experimental methods to research samples.
• analyze the pros and cons of descriptive, correlational, and experimental research designs.
  
  • descriptive pro: observing naturally occurring behaviour and providing detailed observations of individuals.
  • correlational pro: we can see how key variables are related.
  • experimental pro: can be used to test for cause-and-effect relationships.
  • experimental con: limited in how far their results may generalize to real-world situations.

Question 2

2.2 Focus

Answer 2

• what are some of the ways researchers make observations?
• do some research techniques provide stronger evidence than others?

Question 3

Research Design

Answer 3

• research design: a set of methods that allows a hypothesis to be tested. research designs influence how investigators:
  
  • organize the stimuli used to test the hypothesis,
  • make observations,
  • and evaluate the results.
• all research designs have three things in common:
  
  • variables: a property of an object, organism, event, or something else that you can take on different values.
    
    • how frequently you laugh is a variable that could be measured and analyzed.
  • operational definitions: the details that define the variables for the purposes of a specific study.
  • data: the collected observations about the variables of interest.

Question 4

Descriptive Research

Answer 4

• descriptive research answers the question of “what a phenomenon is;”it describes its characteristics.
• once these observations have been performed and the data examined, they can be used to inform more sophisticated future studies that ask “why” and “how” that phenomenon occurs.
• researchers gather data using one or more of the following designs: case studies, naturalistic observation, and surveys and questionnaires.

Question 5

Case Study | Descriptive Research

Answer 5

• case study: an in-depth report about the details of a specific case.
• they are generally reserved for individuals who have a very uncommon characteristic or have lived through a very unusual experience.
• e.g. Phineas Gage (1823-1860)
  
  • had a metal pole launched through his face (into his left eye and tearing through his brain).
  • Gage lived but became more impulsive, inconsiderate, indecisive, and impatient.
• although case studies can be used in the future to gain understanding, are they really science?
  
  • the results from case studies may not be generalizable, but case study patients can be used to test existing hypotheses.
    
    • e.g. a girl with no amygdala (fear control of the brain) still responded to fear stimuli.
  • ​case studies can also be used to find similarities between different concepts.
    
    • e.g. making people associate feelings of fear and anxiety with previously neutral objects helped to make connections in PTSD research.
  • researchers who read case studies can be inspired to make other projects examining different aspects of the issue that was brought to light.

Question 6

Naturalistic Observations | Descriptive Research

Answer 6

• naturalistic observations: unobtrusively observing and recording behaviours as they occur in the subject’s natural environment.
• when making naturalistic observations, researchers must pay attention to specific variables and use operational definitions.
• this method may not always provide researchers with the specific types of information they’re after.

Question 7

Self-Reporting | Descriptive Research

Answer 7

• self-reporting: a method in which responses are provided directly by the people who are being studied, typically through face-to-face interviews, phone surveys, paper and pencil tests, and web-based questionnaires.
• the creation of objective survey and questionnaire items is extremely challenging.
• if you’re studying a subject that some people may not want to openly discuss, questions have to touch the issue without being off-putting.

Question 8

Norms | Descriptive Research

Answer 8

• norms: average patterns of data.
• how do researchers figure out if their questions are valid?
• for clinical questionnaires, the researchers can compare results to a participant’s clinical diagnosis.
• for questionnaires on other phenomena, researchers do pretesting to calculate norms.

Question 9

Correlational Research

Answer 9

• correlational research: involves measuring the degree of association between two or more variables.
• correlations can be visualized when presented in a scatterplot.
  
  • direction—if correlations are positive, it means that the two variables change values in the same direction.
  • magnitude or strength—this refers to how closely the changes in one variable are linked to changes in another variable.
    
    • this magnitude is described in terms of a mathematical measurement called the correlation coefficient.
    • a correlation coefficient of 0 means that there’s no relationship; +1.0 means a very strong positive relationship, -1.0 means a very strong negative relationship.
• correlation is not a measure of causation.

Question 10

Third Variable Problem | Correlational Research

Answer 10

the possibility that a third, unmeasured variable is actually responsible for a well-established correlation between two variables.

Question 11

Illusory Correlations

Answer 11

relationships that really exist only in the mind, rather than in reality.

Question 12

Random Assignment | Experimental Research

Answer 12

a technique for dividing samples into two or more groups in which participants are equally likely to be placed in any condition of the experiment.

Question 13

Confounding Variable | Experimental Research

Answer 13

a variable outside of the researcher’s control that might affect or provide an alternative explanation for the results.

Question 14

Independent Variable | Experimental Research

Answer 14

the variable that the experimenter manipulates to distinguish between two or more groups.

Question 15

Dependent Variable | Experimental Research

Answer 15

the observation or measurement that is recorded during the experiment and subsequently compared across all groups.

Question 16

Between-Subjects Design | Experimental Research

Answer 16

an experimental design in which we compare the performance of participants who are in different groups.

Question 17

Experimental Group | Experimental Research

Answer 17

the group in the experiment that receives a treatment or the stimuli targeting a specific behaviour.

Question 18

Control Group | Experimental Research

Answer 18

the group that does not receive the treatment or stimuli targeting a specific behaviour; this group therefore serves as a baseline to which the experimental group is compared.

Question 19

Within-Subjects Designs | Experimental Research

Answer 19

an experiment design in which the same participants respond to all types of stimuli or experience all experimental conditions.

Question 20

Quasi-Experimental Research

Answer 20

• quasi-experimental research: a research technique in which the two or more groups that are compared are selected based on predetermined characteristics, rather than random assignment.
• these can point out relationships among preexisting groups, but cannot determine what it is about these groups that lead to the differences.