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What is Psychology?
The scientific study of behaviour and mental processes.
What is the difference between behaviour and mental processes?
Behaviour refers to observable and recordable actions, while mental processes are internal processes that cannot be directly observed but can be inferred from their effects on behaviour.
What are the two main types of research discussed in the chapter?
Quantitative research and qualitative research.
What is an Independent Variable (IV)?
The variable that is manipulated by the researcher in an experiment.
What is the ONLY research method that allows researchers to make cause-and-effect inferences?
The experiment.
A researcher wants to study the experiences of one particular adolescent in great depth. Would a quantitative or qualitative approach be more appropriate?
Qualitative research, because it follows an idiographic approach, focusing on an in-depth understanding of a particular case or phenomenon.
What is an operationalization?
It is the process of expressing a theoretical construct in terms of observable behaviour—in other words, deciding how the construct will be measured.
A researcher wants every student in a school to have an equal chance of being selected for a study. Which sampling technique should they use?
Random sampling. Everyone has an equal chance of being selected.
A researcher recruits participants simply because they are students who happen to be available in the school cafeteria. What sampling technique is being used?
Convenience (opportunity) sampling.
A researcher wants to ensure that different important subgroups within a population are fairly represented in the sample. Which sampling technique should be used?
Stratified sampling.
A researcher randomly assigns 60 students to two groups. One group studies with music and the other studies in silence. What is the experimental design?
Independent measures design, because participants are randomly allocated into different groups and the groups are compared.
In a repeated measures experiment, participants perform better the second time simply because they are already familiar with the test. What threat to internal validity is this?
Testing effect. The first measurement can affect subsequent measurements, particularly through familiarity or practice.
A researcher studies whether sleep affects concentration. However, the participants in the sleep-deprivation condition are tested at 8 a.m., while the other group is tested at 8 p.m. What type of problem could this create?
A confounding variable, because the time of testing could influence concentration and therefore distort the relationship between the IV and DV.
A study has excellent control over extraneous variables, but participants behave unnaturally because they know they are in a laboratory. What happens to internal and ecological validity?
Internal validity is likely to be higher, because the study is highly controlled, while ecological validity may be lower because the artificial setting may not reflect real-life behaviour.
In a study, the same participants complete a memory test once after sleeping 8 hours and once after sleeping only 4 hours. What experimental design is being used?
Repeated measures design, because the same participants are exposed to two different conditions.
Researchers want to study whether a new therapy reduces anxiety. They compare two groups, but participants choose which group they want to join. What threat to internal validity is particularly likely?
Selection bias, because the groups may not be equivalent at the beginning of the experiment.
A participant realizes that the researcher expects the experimental group to improve. Without consciously intending to, the participant changes their behaviour to fit what they think the researcher wants. What threat is this?
Demand characteristics. Participants change their behaviour because they understand—or think they understand—the purpose of the experiment.
A researcher unintentionally behaves differently toward participants in the experimental group, influencing their performance. What threat is this, and what design could help control it?
Experimenter bias; a double-blind design could help control it.
Researchers conduct a study in a highly controlled laboratory and obtain very consistent results. However, the behaviour observed may not represent how people behave outside the laboratory. Which type of validity is strongest and which may be weaker?
Internal validity is likely to be stronger, while ecological validity may be weaker: greater control can increase internal validity but reduce ecological validity.
During a six-month experiment, participants naturally become more mature and experienced, and their performance improves. Which threat to internal validity could explain the improvement?
Maturation bias. Changes such as growth or fatigue occurring during the experiment can influence the results.
A researcher wants to investigate whether a new teaching method improves grades. They use an existing morning class for the new method and an existing afternoon class for the traditional method. They did not randomly assign students to groups.
A quasi-experiment, because there is a manipulation/treatment but no random assignment; the researcher uses pre-existing groups.
A researcher measures "academic motivation" by asking students only how many hours they study per week.
What type of validity should the researcher question, and why?
Construct validity. The question is whether the operationalization—hours studied—adequately represents the theoretical construct of academic motivation.
A wildfire naturally destroys one area of a forest but leaves a nearby area untouched. Researchers later compare the two areas to study the effects of the wildfire.
Is this a true experiment, quasi-experiment, or natural experiment? Explain why.
A natural experiment. A real-world event creates the different conditions, and the researcher has no control over the change and does not randomly assign participants/groups.
A researcher investigates the relationship between students' hours of sleep and their GPA. They simply collect information about both variables without manipulating anything.
Can the researcher conclude that lack of sleep causes lower GPA? Explain.
No. This is a non-experimental study, so it can identify a relationship or connection but cannot establish cause and effect.
A researcher wants to determine whether listening to classical music improves students' test performance.
They randomly divide 50 students into two groups. One group studies while listening to classical music, while the other studies in silence. Both groups complete the same test.
However, the researcher personally administers the test to the music group and behaves enthusiastically toward them, while behaving neutrally toward the control group.
Identify: