Research Methods

Systematic Observation

• Naturalistic Observation—observe the behavior of interest in natural environment.
  • Pros: reflects natural/every day behavior
  • Cons: can’t control conditions
• Structured Observation—observe behavior in a lab, where conditions are the same for all
  • Pros: each participant gets an opportunity to display behavior of interest
  • Cons: Unnatural conditions may inhibit natural behavior

Self Reports

• Clinical Interview—flexible interview to obtain insight of participant’s thoughts
  • Pros: Great depth and breadth of info can be obtained
  • Cons: Reporting may be inaccurate because of desire to please the interviewer
• Structured Interview—participants are asked the same questions via self-report instruments (questionnaire, surveys)
  • Pros: Allows for comparison
  • Cons: Not same depths of info acquired in clinical interview

Clinical/Case Study—

• combines interviews, observations, and test scores (sometimes) to assess psychological functioning
  • Pros: provides insight of developmental process
  • Cons: Can’t be used to make inferences about general population
• Ethnography—aimed toward understanding a culture or a distinct social group through entering into close contact
  • Pros: thorough description
  • Cons: may be biased. Findings are exclusive to chosen culture.

General Research Designs

• Correlational Research—research in which the relationship between two sets of variables is examined to determine whether they are associated.
• Represented by a mathematical statistic—correlation coefficient
  • Ranges from +1.0 to -1.0
• Drawback
  • Cannot demonstrate cause-and-effect relationships

Correlational Research

• Positive correlation—indicates that as the value of one variable increases, other variable will also increase.
  • Positive correlation is indicated by a positive number.
  • The greater the number, the stronger the correlation.
  • More study time =  higher test scores (+.85 correlation)
• Negative correlation—tells that as the value of one variable increases, the other variable will decrease.
  • More study time = less hours spent partying (-.85  correlation)
  • Ranges between 0 and –1.0
• Little or no relationship
  • Number of study hours and height (-.02)
  • Lack of relationship would be indicated by correlation close to 0

General Research Designs

• Experimental Design—the investigation of the relationship between two (or more)variables by deliberately changing one variable in a controlled situation and observing the effects of that change on other aspects of the situation. 
  • Only method that can establish cause-and-effect relationships.
  • Experimental manipulation—the change that the experimenter deliberately makes.

Experimental Design

• Experimental research requires comparison between, at least two groups.
  • Experimental/Treatment group—group that receives a treatment
  • Control group—group that receives no treatment
    • Treatment—manipulation implemented by experimenter.
    • Using both groups rules out external factors.
  • Independent variable—manipulated variable
  • Dependent variable—measured variable that is expected to change as a result of manipulating the IV

Experimental Design

• Random assignment to condition—participants are assigned to groups based on chance.
  • Make experiments valid
  • Flip the coin method
    • Guarantees equal chance of characteristic distribution to various groups.
• Significant outcome—meaningful results that lead to confirmation of hypotheses.
• Replicated research—repeated research using different procedures, settings, groups of people to increase confidence in previous findings

Developmental Research Design

• Cross-Sectional Research—compares people of different ages at the same point in time
  • Differences among groups of people
  • e.g. IQ scores between 25, 45, and 65 year olds.
• Limitation
  • Cannot be sure that different findings are due to age differences alone.
  • Cohort Effects
    • e.g. people in older group may belong to a cohort that was less likely to attend college than younger cohorts.

• Longitudinal Research—traces the behavior of one or more participants as the participants age
  
  • Asses change in behavior over time
  • e.g. intellectual development during adulthood.
    • IQ test every 20 years to same group of people (25, 45, 65 yrs).
  • Limitations
    • Time expenditure
      • Researcher must wait as participants age
    • Drop out
      • Move away, die, or simply stop showing up
    • Participants may become “test-wise”

• Sequential Research—combines cross-sectional and longitudinal approaches
  • Makes up for limitations in cross-sectional and longitudinal
  • Takes a number of different age groups and examines them at several points in time
    • e.g. group of 3, 5, and 7 year olds and examines them every 6 months for a period of several years.
  • Limitations
    • Same as Cross-Sectional and Longitudinal