PSYC289 - Unit 2: Psychological Research

What are the three sets of interrelated goals shared by psychologists and other scientists?

measurement and description, understanding and prediction, and application and control.

Measurement and description

Scientific observation first depends on the investigator finding a way to measure the phenomenon of the study so that it makes it possible to describe behaviour clearly and precisely.

Understanding and prediction

Scientists believe that they understand events when they can explain the reasons for the occurrence of those events. They develop hypotheses as the basis for testing predictions.

Application and control

Scientists hope that their investigations yield data and information that can be used to solve problems. When phenomenon is understood it is easier to assert control over it.

Empiricism

the premise that knowledge should be acquired through observation

Hypotheses

a tentative statement about the relationship between two or more variables.

Variable

any measurable conditions, events, characteristics, or behaviours that are controlled or observed in a study

Theory

a system of interrelated ideas used to explain a set of observations

Step one of scientific investigation

Formulate a testable hypothesis. To be testable, scientific hypotheses must be formulated precisely, and the variables under study must be clearly defined.

Step two of scientific investigation

Select the research method and design the study with methods such as experiments, case studies, surveys, naturalistic observation, and so forth.

Step three of scientific investigation

Collect the data. Techniques to collect data include direct observation, questionnaires, interviews, psychological tests, physiological recordings, and examination of archival records.

Step four of scientific investigation

Analyze the data. Observations from the study are usually converted into to numbers which can be analyzed to see whether or not the hypothesis was supported.

Step five of scientific investigation

Report the findings (and draw conclusions). The final step in a scientific investigation is to write up a concise summary of the study and its findings. Findings are then published in journals where they undergo rigorous peer review in order to preserve scientific integrity and accuracy.

The scientific approach…

…offers clarity and precision, as well as relative intolerance of error.

Operational definition

describes the actions or operations that will be used to measure or control a variable.

Naturalistic observation

Observing participants within their natural environment/ Strengths: Allows study under conditions that are less artificial than experiments. Weakness: Difficult to make observations unobtrusively.

Case Study

An in-depth investigation of a participant or group of participants. Strengths: can provide compelling, real-life illustrations that bolster a hypothesis or theory. Weaknesses: they can be highly subjective.

Survey

questionnaires or interviews used to gather information about specific aspects of participants' behaviour. Strengths: used to obtain information on aspects of behaviour that are difficult to observe directly & relatively easy to collect Weaknesses: participants' tendency to cooperate with surveys appears to have declined noticeably in recent decades & depend on self-report data

Descriptive/correlational research

gives researchers a way to explore questions they could not examine with experimental procedures be it for ethical or practical reasons.

Key disadvantage of descriptive/correlational research

researchers cannot control variables during these studies and, therefore, these methods cannot be used to demonstrate cause-and-effect relationships between variables.

Experiment

a research method in which the investigator manipulates a variable under carefully controlled conditions and observes whether any changes occur in a second variable as a result.

Independent variable

a condition or event that an experimenter manipulates in order to see its impact on another variable.

Dependant variable

is the variable that is thought to be affected by manipulation of the independent variable.

Experimental groups

are the groups of people who receive special treatment during experiments in regards to the independent variable, while the control group do not

Extraneous variable

variables other than the independent variable that seem likely to influence the dependent variable in a specific study

Confounding variable

occurs when two variables are linked in a way that makes it difficult to sort out their specific effects

Within-subjects design

happens when the same participants are studied under both experimental and control conditions, they become their own control group

Between-subjects design

happens when separate groups of participants are studied under one or the other condition, they comparison of the study then becomes "between" groups

Field experiments

research studies that use settings that are very much like real life; in fact, the research may occur in the context of everyday life and events.

Random assignment

occurs when all participants have an equal chance of being assigned to any group or condition in the study.

What can we safely conclude when variables X and Y are correlated?

We can safely conclude only that X and Y are related. We do not know how X and Y are related. We do not know whether X causes Y or Y causes X or whether both are caused by a third variable.

Statistics

is the use of mathematics to organize, summarize, and interpret numerical data.

Descriptive statistics

are used to organize and summarize data.

Central Tendency

three measurements used to obtain the average scores of a set of data.

Mean (central tendency)

the arithmetic average of the scores in a distribution. It is obtained by adding up all the scores and dividing by the total number of scores.

Median (central tendency)

the score that falls exactly in the centre of a distribution of score. Half of the scores fall above the median and half fall below it.

Mode (central tendency)

The more frequent score in a set of data.

Variability

refers to how much the scores in a data set vary from each other and from the mean

Standard deviation

an index of the amount of variability in a set of data. A large standard deviation indicates that there is great variability in a sample while a small standard deviation indicates that there is a smaller one.

A positive correlation…

…exists when both variables relate in the same direction, that direction can be up or down

A negative correlation…

…exists when variables relate in the opposite direction.

What does the size of a correlation coefficient indicate?

The strength of the association between two variables.

What does a correlation coefficient of 0 indicate?

There is no relationship between the two variables.

What values indicate a perfect correlation?

+1.00 or -1.00

Does a high correlation between two variables imply a causal relationship?

No, variables can be highly correlated without being causally related.

Inferential statistics

are used to interpret data and draw conclusions

Replication

the act of repeating a study to see whether the results are duplicated.

A sample

is the collection of participants selected to participate in a study.

Sampling bias

occurs when a sample is not representative of the population it was taken from.

Placebo effect

a powerful phenomenon that occurs when the expectations of participants lead them to experience some change even though they receive empty, fake, or ineffectual treatment.

Social desirably bias

can lead to participants self-reporting inaccurate details about themselves in order to present themselves as more socially acceptable.

The halo effect occurs when…

…one's overall evaluation of a person, object, or institution spills over to influence more specific ratings (eg. a supervisor's global assessment of an employee's merit might sway specific ratings of the employee's dependability, initiative, communication, knowledge, and so forth)

Experimenter bias

occurs when a researcher's expectations or preferences about the outcome of a study influence the results obtained.

Double-blind procedure

a research strategy in which neither participants nor experimenters know which participants are in the experimental or control groups.