Experimental Methods and Research Designs

Social Context and Confederates

• The independent variable often involves a person's social context.
• Social psychologists frequently manipulate the social context using helpers known as confederates.

Confederate Definition

• A confederate is a person assigned a role in a study to manipulate the social context.
• They may appear as regular participants but are working with the experimenter to influence the situation.

Experimental and Control Groups

Experimental Group

• The experimental group consists of participants who receive the treatment or manipulation under study (exposed to the independent variable).

Control Group

• The control group is composed of participants as similar as possible to the experimental group.
• They're treated identically to the experimental group, except they don't receive the manipulated factor (the independent variable).
• The control group serves as a baseline for comparison to assess the effects of the independent variable.

Example Experiment: Trust and Social Bonds

• Psychologists investigate factors influencing social bonds, such as the feeling of being trusted.
• One indicator of trust is when someone risks something of value for another person.

Cruwys & Others (2020) Experiment

• A study tested the prediction that perceived trust enhances social closeness.
• Participants were told they would interact with another person who was delayed.
• Participants completed a "taste test" of three juice bottles.
• The "interaction partner" (a confederate) arrived and, to save money, was told to use the same bottles.

Conditions:

1. Risk-Taking Condition: The confederate drank directly from the bottles without cleaning.
2. Risk-Avoidant Condition: The confederate cleaned the bottles with disinfecting wipes before drinking (avoiding lip contact).
3. Control Condition: The confederate received fresh bottles.

Measures:

• Participants rated how much they felt the confederate trusted them and their closeness to the confederate.

Results:

• Participants felt more trusted by the confederate who drank directly from their bottles.
• They also reported feeling closer to the confederate in the risk-taking condition compared to the risk-avoidant condition.
• The level of trust explained the increased feelings of closeness.
• Taking a risk that expresses trust makes others feel closer to the risk-taker.

Deception:

• The study involved deception because participants were misled about the partner being late and the confederate's true role.
• Confederates actually drank from fresh bottles to avoid any real risk.

Review of Concepts

• The study used a confederate to manipulate risk-taking.
• The independent variable was risk-taking, operationalized by the confederate's behavior.
• The dependent variables were participants' feelings of trust and closeness.

Importance of the Control Group

• The control group (receiving new bottles) was crucial for establishing a baseline.
• It helped determine whether risk-taking led to increased trust or risk avoidance to decreased trust.
• It also accounted for the possibility that simply being in the experiment and doing the taste test might affect trust and closeness.
• Without the control group, there would be no reference point for comparison.

Experimental vs. Control Groups

• Experiments compare groups exposed to different versions of the independent variable.
• The experimental group is exposed to the change represented by the independent variable.
• The control group is treated the same as the experimental group but does not experience the change (independent variable).
• The control group provides a basis for testing the effects of the independent variable.

Random Assignment

• Random assignment means participants are assigned to groups by chance to minimize pre-existing differences.
• It is essential for assuming no systematic differences between groups.
• If random assignment is used, any differences observed are likely due to the manipulated variable.
• Random assignment relies on the idea that potential differences between groups will cancel out over the long run if assignment is done by chance.

Improving Random Assignment

• Random assignment doesn't guarantee equivalent groups, especially with small sample sizes.
• Starting with a large pool of people improves the effectiveness of random assignment.
• With larger samples, individual differences are more likely to be evenly distributed across groups.

Experimental vs. Correlational Studies

• Correlational studies can show relationships between variables, but not causation.
• Experimental studies, through manipulation and random assignment, can demonstrate cause and effect.

Example: Meaning in Life and Happiness

• Correlational studies show a positive correlation between meaning in life and happiness.
• It's unclear if meaning in life causes happiness or vice versa.

King et al. (2006) Experiment

• Participants were randomly assigned to listen to happy or neutral music.
• They then rated their meaning in life.
• Those who listened to happy music rated their lives as more meaningful.
• The independent variable was mood (positive vs. neutral), operationalized by music type.
• The dependent variable was meaning in life, measured by questionnaire ratings.
• Random assignment allowed the conclusion that happy music caused an increase in meaning in life.

Independent and Dependent Variables

• The independent variable is the manipulated factor (potential cause).
• The dependent variable is the outcome that may change due to the manipulation (the effect).
• Researchers manipulate the independent variable to measure its effect on the dependent variable.
• Experiments can have multiple independent and dependent variables.

Mnemonic

• Independent Variable: Controlled by the investigator.
• Dependent Variable: "Depends" on the participants.

Operationalizing Variables

• Independent and dependent variables can be operationalized in various ways.
• Social context can be manipulated using confederates.

Descriptive Research

• Descriptive research describes the basic dimensions of a variable.

Examples of Descriptive Findings:

• Maasai: Averaged 5.4 on the Satisfaction with Life Scale, despite challenging living conditions.
  *The Maasai are known to practice female genital mutilation as they enter puberty, child marriage, and polygamy.
• Old Order Amish: Averaged 4.4 on the 7-point scale, even though they reject modern aspects of life.

Correlational Research

• Correlational research examines the relationship between two or more variables.
• It determines whether and how two variables change together (co-relation).
• When variables are correlated, one can be predicted from the other.

Correlation Coefficient

• The degree of relation between two variables is expressed as a correlation coefficient (r).
• Values range from -1.00 to +1.00.
• It indicates both the strength and direction of the relationship.

Strength:

• The closer the number is to +1.00, the stronger the relationship.

Direction:

• Positive Sign (+): Variables change in the same direction (as one increases, the other increases).
• Negative Sign (-): Variables change in opposite directions (as one increases, the other decreases).
• Zero Correlation: No relation between the variables.

Correlation vs. Causation

• Correlation does NOT equal causation.
• Correlation only means that two variables change together.
• Predicting one event based on another doesn't imply causation.

Third Variable Problem

• The third variable problem occurs when an unmeasured variable accounts for the relationship between two others.
• Also known as confounds.

Big Data in Psychological Research

• Psychologists use large, naturally occurring datasets (Big Data) to study human behavior.
• Examples of Big Data include public records and online tracking.

Uses of Big Data:

• Estimating the number of people with diverse sexual orientations and gender identities.
• Predicting risk for psychological disorders.
• Measuring the link between racism and health disparities.

Advantages of Big Data:

• Often represent actual behavior and objective events.
• Provide a direct look at human life.

Ethics and Privacy:

• Using public records and social media data raises ethical and privacy concerns.
• It is essential to read user agreements and be cautious online.

Longitudinal Designs

• Longitudinal research involves obtaining measures of variables over multiple time points.
• It can suggest potential causal relationships by ensuring that the cause precedes the effect in time.

Nun Study

• The Nun Study (1986) followed 678 School Sisters of Notre Dame.
• The nuns completed psychological and physical measures annually.
• Their homogenous living conditions and backgrounds minimize extraneous third variables.

Findings:

• Positive emotions expressed in autobiographies at age 22 were associated with a 2.5-fold difference in mortality risk in their 80s and 90s.
  *The data showed that women who included positive emotion in their autobiographies when they were in their early 20s were 2.5 times more likely to survive some 60 years later.
• A similar finding was replicated with autobiographies of famous psychologists.

Limitations:

• Even longitudinal studies cannot definitively prove causation.
• Other factors, like childhood experiences or genetic factors, may influence both happiness and longevity.