Psychology as a Science

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Chapter 1Psychology as a Science
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Scientific Methods

• - are a set of procedures used to gather,
  analyze, and interpret information.
• - their purpose is to minimize error and Lead to
  dependable generalizations.

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Critical Thinking

• - is the process of
• deciding what to believe and how to act
• based on a careful evaluation of the evidence
• and ruling out alternative explanations.

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What makes a good theory?

• 1. Predictive accuracyCan the theory reliably
  predict behavior?
• 2. Internal coherenceAre there logical
  inconsistencies between the theoretical ideas?

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What makes a good theory?

• 3. Being economicalDoes the theory include only
  what is necessary to explain the phenomenon in
  question?
• 4. FertilityDoes the theory generate research,
  and can it be used to explain a wide variety of
  behavior?

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How About Common Sense?

• Absence makes the heart grow fonder vs. Out of
  sight, out of mind.
• We look for patterns.
• We learn from experience.
• Sometimes we are wrong.
• Data helps, but is no guarantee.

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Show me the evidence!

• Keep in mind that --
• Some things seem true that are not.
• Some things seem false that are true.
• Some things we just dont know.
• And some things we discover, disproving what we
  thought we knew!

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Research Three basic techniques of data
collection

• Three basic techniques of data collection are
• self-reports
• direct observations
• archival information

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Observational Research

• Case study in-depth analysis of a single subject
• Naturalistic observation investigating behavior
  in its natural environment
• Laboratory observation

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Advantages of Observational Research

• Researchers can
• Watch behavior in its wholeness, providing the
  full context in which to understand it.
• Record rare events that may never occur in a
  controlled laboratory environment.
• Systematically record events previously observed
  only by nonscientists.
• Observe events that would be too risky,
  dangerous, or unethical to create in the
  laboratory.
• One advantage of case study research is that it
  involves in-depth analysis of a single subject.

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Problems of Observational Research

• Observation of events can alter the participants
  behavior and taint the data
• Ethical problems involving invasion of others
  privacy
• One problem with case study research is that
  researchers must be extremely cautious when
  generalizing from a single case to the entire
  population.

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Survey Research

• A survey is a structured set of questions or
  statements to measure peoples attitudes,
  beliefs, values, or behavioral tendencies.

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Survey Research

• Questions that are too vague, misdirected or
  biased will not yield the intended information.
• Questions asked to people who do not represent
  the population of interest will yield biased or
  incorrect results.

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Survey Sampling

• Shere Hite
• Sampled 100,000 people
• received 4500 returns
• reported that 70 of women were having affairs
• (Other surveys found only 1/7)

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Correlational Research

• The variables in correlational research are not
  controlled by the researcher.
• However, the measures yield numbers that can be
  analyzed using correlational statistics.

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Correlational Statistics

• Show the direction and Strength of the
  relationship between variables
• The correlation coefficient ranges from 1.00 to
  1.00
• It is a statistical measure of the direction and
  strength of the relationship between two
  variables.

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Correlational Research
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High Positive Correlation
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Negative Correlation
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Positive Correlation
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Low Negative Correlation
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Zero Correlation
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You cannot determine Causation from Correlation
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Correlation and Causation

• Three possible cause-effect relations

could cause
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Experimental Variables

• Independent variable the manipulated variable
  tested as the possible cause of changes in the
  other variable
• Dependent variable the variable whose measured
  differences or changes are considered to be the
  effect of the manipulated changes in the
  independent variable

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Experimental Research Determination of
Cause-Effect Relationships through manipulation
control

• Experimenters manipulate one variable
  (independent)by exposing participants to
  contrasting levels, and then observe the effect
  on another variable (dependent)not manipulated.
• All other important variables are controlled.

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The Basic Elements in an Experiment
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The Experiment

• Independent Variable
• manipulated (different in each group)
• cause of the change in the dependent variable
• Dependent Variable
• measured effect
• may change in response to manipulations of the
  independent variable

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Experimental Manipulation

• Experimental Condition
• exposes participants to the treatment version of
  the independent variable
• Control Condition
• Exposes participants to no treatment or a placebo
  version of the independent variable
• serves as a comparison for evaluating the effect
  of the treatment

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Random Assignment

• assigning participants to experimental and
  control conditions by chance
• Purpose to minimize the influence of
  preexisting differences on the different groups

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Placebo Controls

• Placebo
• A treatment that looks like the real one, but
  lacking the active agent
• Placebo Effect
• any effect on behavior caused by a placebo,
  usually those caused from believing one has
  experienced genuine treatment

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Double-blind Procedure

• an experimental procedure in which both the
  research participants and the research staff are
  ignorant (blind) about whether the research
  participants have received the treatment or a
  placebo
• commonly used in drug-evaluation studies

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Comparing Research Methods
Research Method Basic Purpose
How Conducted What is
Manipulated
Descriptive To observe and
Case studies, surveys, Nothing record
behavior and naturalistic
observations
Correlational To detect naturally
Computing statistical Nothing occurring
relationships association, sometimes to
assess how well among survey one variable
predicts responses
Experimental To explore cause Manipulating
one or Independent and effect more
factors and using variable(s) random
assignment to eliminate preexisting diff
erences among subjects
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The Scientific Method

• Replication
• repeating the essence of a research study to see
  whether the basic finding generalizes to other
  participants and circumstances
• usually with different subjects in different
  situations (by different researchers)