用户:Grotton JXz Donbrako/Psychology/Chapter 2

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Research Methods

• "How do you do research in psychology?"
• Psychology uses the scientific process:
  • Question
  • Hypothesis
  • Prediction
  • Data
  • Interpretation

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• Hindsight bias is the tendency of people to overestimate their ability to have predicted an outcome that could not possibly have been predicted.
• However, the goal of science is to be predictive; that is, determine an outcome before it happens, not after.

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• Research question:
• What are some relationships between these variables
  • Coffee intake and running speed?
  • Showering and body odor?
  • Studying and grades?
  • Mass of an object and its gravitational force?

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• Hypothesis: Usually an ‘if, then’ statement or simply a prediction about some event.
  • "If people are given money, they experience greater happiness than if given candy."
  • ↑How do we measure happiness?
• Independent variable: The variable that influences the dependent variable.
• Dependent variable: A variable that depends on the independent variable.
• Theory: aims to explain a broad set of phenomenon.

• Operational Definitions：Definitions of variables in research need to be quantifiable and observable. They need to be operationally defined.

• "Research aims to be valid and reliable"
  • Validity refers to whether the research measures what the researchers set out to measure.
    • "If you have a scale, and it says you weigh 100lbs., but on every other scale you step on, the scale says 180lbs., the scale would not be a ‘valid’ measure of your weight."
  • Reliability refers to whether the same results can be produced under similar conditions.
    • "If you stepped on the scale and it said 100lbs., and then five minutes later stepped on the same scale again, and it said 130lbs., the scale would not be a ‘reliable’ measure of your weight."

• Participants are the people or subjects in your study.
• Sampling: The selection of participants.
• Population is the large set of individuals from which a sample was taken.
• Representative: A sample that accurately reflects the larger population.

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• "Wearing a red shirt in a large crowd gets you more attention."
  • What is my hypothesis?
  • What must be operationally defined?
  • Who is my sample?
  • Who is my population?
  • Is the sample representative?

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• Random Selection means that every member of the population has an equal chance of being selected.
  • How could we randomly select in the previous example?
• Stratified Sampling: A process that allows a researcher to ensure the sample represents the population on some criteria.
  • If I want to research whether different racial groups respond differently to a survey, I could select 10 Caucasians, 10 Asians, 10 African Americans…

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• Psychologists prefer experiments because they can establish a cause-effect relationship.
  • Laboratory Experiments are conducted in a lab.
  • Field Experiments are conducted in the ‘real’ world. Researchers go out and manipulate some variable and observe the effect.

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• Confounding variable: A confounding variable is any difference between the experimental controls and the control conditions, except for the independent variable, that might affect the dependent variable.
  • A researcher must try to isolate variables or control for “confounding variables”
  • "If I am studying whether the amount of time spent studying is associated with better grades, what are variables that may influence this relationship other than studying?"

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Groups

• An experiment must have a control group and an experimental group.
• The control group is the group that does not receive the independent variable.
• The experimental group is that which receives the independent variable.
  • "Drinking coffee before running makes one run faster."
  • After gathering a sample, who is my experimental group and who is control group?

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Terms

• Assignment: Assignment is the process by which participants are put into a group, experimental or control.
• Random assignment: The process of randomly assigning participants to either the control or experimental group.
• Participant-relevant confounding variables: If participants were given the opportunity to choose which group to be in, the results might become biased.
  • What if in my coffee experiment, I allow participants to join which ever group they want?
• Group-matching: If one wanted to match for sexual orientation, eye color, skin color, or something other variable, then group matching is the process of assigning individuals to groups based on some criteria.
• Situation-relevant confounding variables: When conducting an experiment, both groups (experimental and control) must be subject to the same environment.
• Experimental Bias: The tendency for researchers to treat members of the experimental and control groups differently.
  • If the aim of my study is confirm my hypothesis, I may interpret the results differently than someone who is not involved or does not have an interest.

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Controlling for Bias (Experimental Designs)

• Single Blind: Participants do not know whether they're in the experimental group or the control group.
• Double Blind: Neither the participants nor the research knows who is in which group.

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Placebo

• Placebo is a substance that has no therapeutic effect; it is often used in control groups for testing new drugs.
• Placebo effect: Participants feel a "psychological" effect, but have not been given a real substance that would cause “real” physiological differences in their body.

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Correlational Method

• Correlation is a statistical measure that indicates the extent to which two or more variable fluctuate together. 
• A correlation expresses a relationship between two variables without ascribing a cause.
• Correlation does not equal causation.

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• A positive correlation between two things means that the presence of one thing predicts the presence of the other.
• A negative correlation means that the presence of one thing predicts the absences of the other.

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• Predict the correlation
  • Drinking water and feeling thirsty
  • Studying and amount of free time
  • Colour of t-shirt worn on exam day and exam grade
  • Number of hours spent studying and grades
  • Amount of coffee drunk and talkativeness
  • Staying up all night and fatigue
  • Number of fictional novels read and driving ability

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• "Why use correlations, why not always conduct an experiment?"
• Sometimes correlations are the best research method because you cannot manipulate the data in an experiment.
  • Does weather have an effect on shop lifting? Is there any way we can manipulate the weather?

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Survey

• Conducting a survey involves asking participants to complete a questionnaire.
• Using the survey method means that one cannot control for certain confounding variables.
• Survey method is subject to the social desirability effect: the tendency of survey respondents to answer questions in a manner that will be viewed favorably by others.

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Naturalistic observation

• Naturalistic observation: Researchers go out and observe participants in their natural habitat without interfering at all
• Naturalistic observation is different from field experiments because in naturalistic observation, researchers do not interfere.

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Case Studies

• The case study method is often used in clinical psychology.
• Case studies allow researchers to get a picture of a small group of people (as little as one), but this means that the findings cannot be generalized to any population.
• An example of a case studies may be studying a rare psychological disorder.

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（待补充）

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