The Scientific Method

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• The Scientific Method

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Key Issues in Human Development

• 1- Heredity and Environment
• Heredity-oriented theories assume an important
  role of underlying biological structures. They
  point out that specific genes may underlie
  development and behavior.
• Environmental explanations focus on the
  individuals experience pertaining to thinking,
  health, and social factors

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Key Issues in Human Development

• Heredity and environment interact, but theorists
  still disagree over the relative contributions of
  each and the manner of their interaction.
• The position that the theorists take on this
  question determines the direction and nature of
  their research

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Key Issues in Human Development

• 2- Maturation and Learning
• Maturation refers to biological processes.
• Learning refers to change over time related to
  practice or experience.
• When development is considered in terms of
  maturation and learning, the emphasis is on time.
• Example How is the biological event of menopause
  affected by a womans lifestyle (experience)?

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Key Issues in Human Development

• 3- Critical Versus Sensitive Periods
• Optimal periods during which certain types of
  learning occur best
• Readiness refers to reaching a maturational point
  at which a specific behavior can be learned
• Examples
• The effects of certain diseases during pregnancy
• Acquiring a second language during an early age
• The critical time span several hours after birth
  during which goslings become bonded to the mother
  (imprinting)

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The Scientific Method
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What Makes Research Scientific?

• 1- Precision
• 2- Skepticism
• 3- Reliance on Empirical Evidence
• 4- The Principle of Falsifiability
• 5- Openness? Replication

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• Science becomes dangerous only when it imagines
  that it has reached its goal.
• (George Bernard Shaw)

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Issues in Data Collection

• 1- Sampling
• Random Sampling
• Representative Sample
• 2- Reliability
• The degree of consistency with which a
• test or scale measures something.
• 3- Validity
• The extent to which a test or scale measures
• what it is supposed to measure

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Validity

• 1- Internal Validity
• What happened to the experimental group actually
  caused the new behavior.
• 2- External Validity
• The extent to which an experiment corresponds to
  what happens in the real world
• 3- Construct

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How Do Psychologists Observe and Describe
Behavior?

• 1- Descriptive Method
• 2- Correlational Studies
• 3- Experimental Method

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Methods of Studying Behavior

• 1- Descriptive Methods
• Approaches that primarily involve the observation
  and description of behavior

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Methods of Studying Behavior

• 2- Correlational Studies
• Examine the relationship between two variables to
  determine whether they are associated or
  correlated

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Methods of Studying Behavior

• 3- Experimental Methods
• Approaches that go beyond description and attempt
  to determine what causes what in development and
  behavior

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Descriptive Approaches

• 1- Case Studies
• 2- Systematic Observation
• 3- Questionnaires and Surveys
• 4- Psychological Testing
• 5- Developmental Research Design

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Case Study

• Sometimes are called baby biographies
• They involve extensive interviews with a
  particular individual or a small group of
  individuals
• Drawbacks
• 1- The lack of standardization
• 2- Reliance on language

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Systematic Observation

• Naturalistic Observation
• Occurs in a natural setting such as studying apes
  in the wild or people in bars

• Laboratory Observation
• The psychologist has more control
• One shortcoming is that the presence of
  researchers and special equipment may cause
  subjects to behave differently

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Questionnaires and Surveys

• Interview that ask people directly about their
  experiences, attitudes, or opinions
• Drawbacks
• The difficulty of getting a representative sample
  
• When dealing with volunteers, we may have
  volunteer bias

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Psychological Tests

• Sometimes called assessment instruments
• Are procedures used for measuring and evaluating
  personality traits, emotional states, aptitudes,
  interests, abilities, and values

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Psychological Testing

• Objective Tests
• Also called Inventories
• Measure beliefs, feelings, or behaviors of which
  the individual is aware
• Have more reliability and validity

• Projective Tests
• Designed to tap unconscious feelings or motives

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Projective Tests

• 1- Association Techniques
• The Rorschach Test
• The Word Association Test
• 2- Completion Techniques
• Sentence Completion Tests
• Rosenzweig Picture Frustration Study

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The Rorschach Projective Test
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Projective Tests

• 3- Construction Techniques
• The Thematic Apperception Test (TAT) The
  Picture Projective Test (PPT)
• 4- Expression Techniques
• The Draw-a-person Test
• The House-tree-person Test

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Developmental Research

• 1- The Longitudinal Design
• 2- The Cross-Sectional Design
• 3- The Sequential-Cohort Design

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1- The Longitudinal Design

• A group of individuals is studied repeatedly at
  different points in the lifespan
• Drawbacks
• a. Large investments in time and money
• b. Some subjects drop out or die
• c. Some subjects become testwise
• d. Changes in individuals may be due to the time
  of measurement rather than development

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2- The Cross-Sectional Design

• Compares individuals of different ages at one
  point of time
• Drawbacks
• a. It tells us more about age groups than about
  development within the individuals
• b. The cohorts differ not only in chronological
  age but also in the time period in which they
  were born

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3- The Sequential-Cohort Design

• A mix of the two types of research
• Example
• Studying a group of 4-year-olds, a group of
  8-year-olds, and a group of 12-year-olds each 2
  years comparing them longitudinally and
  cross-sectionally

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• The Experimental Method in Psychology

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Defining Psychology

• Psychology is the scientific study of behavior
  and mental processes and how they are affected
  by an organisms physical state, mental state,
  and external environment.

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Correlational Study by Craig Anderson Karen
Dill (2000)

• The Effects of playing violent video games on
  behavior, especially aggressive behavior

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Correlational Study by Anderson and Dill (2000)

• Method
• A correlational study based on questionnaires and
  personality measures administered to a large
  number of college students

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Correlational Study by Anderson and Dill (2000)

• Results
• Analysis of data indicated that playing violent
  video games was strongly and positively
  correlated with two factors
• a. Aggressive delinquent behavior in real life
• b. Aggressive personality characteristics

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Plausible Causes for Aggressive Behavior
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Plausible Causes for Aggressive Behavior
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Plausible Causes for Aggressive Behavior
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Correlational Studies

• Examine the relationship between two variables to
  determine whether they are associated or
  correlated
• Establishing a correlation between 2 variables
  does not indicate causality

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Experimental Methods Anderson and Dill (2000)

• The Effects of playing violent video games on
  behavior, especially aggressive behavior

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Hypothesis

• Playing violent video games would increase
  aggressive behavior

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The Outcome of the Experiment

• The results confirmed that participants who
  played a violent video game behaved more
  aggressively than participants who played a
  nonviolent video game.

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Experimental Methods
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Experimental Methods

• They tell us about cause and effect
• The investigator manipulates one set of variables
  (independent variables) and observes their
  influence on another set of variables (dependent
  variables)
• To establish causality, experimenters compare
  different groups, experimental groups and control
  groups.

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Experimental Design

• Questions
• Who are the subjects?
• What is the independent variable?
• What is the variable that is going to change
  because of manipulation?
• What is the dependent variable?
• If there were changes in behavior, what was the
  causative agent?
• What was the outcome of the experiment in one
  sentence?

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Ethics in Research

• 1- Freedom from Harm
• 2- Informed Consent
• 3- Use of Deception
• 4- Maintenance of Privacy

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Understand these Terms

• Hypothesis
• Correlational studies
• Experimental method
• Independent variable
• Dependent variable
• Experimental group

• Control Group
• Validity
• Construct
• Reliability
• Representative sampling
• Causality

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Design Your Own Research

• 1- You want to examine the effect of watching
  violent movies on the behavior of children, what
  design are you going to use, cross-sectional,
  longitudinal, or sequential-cohort design?
• 2- What is your hypothesis?
• 3- How many groups are you going to have? Why?
• 4- What is the population you are going to
  experiment on? How are you going to select your
  sample?

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• 5- If you want to establish causality, what
  technique are you going to use, correlational,
  observational, case studies, or experimental?
• 6- What is the methodology?
• 7- Where are you going to conduct the experiment?
• 8- What are the dependent variables?
• 9- What are the independent variables?
• 10-Do you think your experiment has internal and
  external validity? Why?

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