the scientific method 1. 2 3 key issues in human development 1- heredity and environment...
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The Scientific Method
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Key Issues in Human Development
1- Heredity and EnvironmentHeredity-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 individual’s 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 LearningMaturation 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 woman’s lifestyle (experience)?
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Key Issues in Human Development
3- Critical Versus Sensitive PeriodsOptimal periods during which certain types of
learning occur bestReadiness refers to reaching a maturational point
at which a specific behavior can be learned Examples:The effects of certain diseases during pregnancyAcquiring a second language during an early ageThe 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- SamplingRandom SamplingRepresentative Sample
2- ReliabilityThe degree of consistency with which a test or scale measures something.
3- ValidityThe extent to which a test or scale
measureswhat it is supposed to measure
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Validity1- 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 TechniquesThe 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 moneyb. Some subjects drop out or diec. Some subjects become testwised. 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 organism’s 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)
MethodA 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)
ResultsAnalysis 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 GroupValidityConstructReliabilityRepresentative
samplingCausality
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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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