Mind, Behavior and Science

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Chapter 2
Research Methods
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How Do Psychologists Develop New Knowledge?

• Empirical investigation The collecting of
  objective information firsthand by making careful
  measurements based on direct experience/observatio
  n
• Observation must be objective!!!

• Theory Testable explanation for a set of facts
  or observations. In science, a theory is NOT
  just speculation or guess.

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Objective or Inference?

• He had his notebook open in from of him, but he
  took no notes and he looked at his watch 23 times
  during the lecture.
• When the therapy session was over, she was so
  anxious to get away that she left her purse and
  umbrella.
• People must have assumed that the man lying
  beside the street was drunk and they made no
  effort to help him.

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The Five Steps of the Scientific Method
Developing a hypothesis

• Hypothesis A statement predicting the outcome
  of a scientific study

Performing a controlled test
Gathering objective data

• Operational definitionsExact procedures used in
  establishing experimental conditions and
  measurement of results

Analyzing the results
Publishing, criticizing, and replicating the
results
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The Five Steps of the Scientific Method
Developing a hypothesis

• Independent variable The variable manipulated
  by the experimenter

Performing a controlled test
Gathering objective data

• Random presentation Using chance alone to
  determine the order in which the stimulus is
  presented

Analyzing the results
Publishing, criticizing, and replicating the
results
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The Five Steps of the Scientific Method
Developing a hypothesis

• Dependent variable The measured outcome of a
  study the responses of participants in a study

Performing a controlled test
Gathering objective data
Analyzing the results
Publishing, criticizing, and replicating the
results
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Dependent v. Independent Variables

• The effect of breakfast on academic performance.
• The effect of studying on AP Exam scores.
• The effect of hitting someone over the head with
  a baseball bat on dizziness.
• The effect of Mint Oreos on body weight.
• The effect of sleep on mood.
• The effect of doggies running into sliding glass
  doors on their intelligence. ?

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Experimental Method

• Experiment Researcher controls all conditions
  and directly manipulates conditions
• Confounding variables Have an unwanted
  influence on the outcome of an experiment
• Controls Constraints to ensure that each
  subject has the exact same conditions
• Control Group v. Experimental Group
• Random assignment Equal chance of being chosen
  for the experimental group

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The Five Steps of the Scientific Method
Developing a hypothesis
Performing a controlled test
Gathering objective data

• Based on statistical analyses of results, the
  hypothesis is accepted or rejected

Analyzing the results
Publishing, criticizing, and replicating the
results
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The Five Steps of the Scientific Method
Developing a hypothesis
Performing a controlled test

• Researchers must find out whether their work can
  withstand the scrutiny of the scientific community

Gathering objective data
Analyzing the results

• Replication Doing a study over to see whether
  the same results are obtained

Publishing, criticizing, and replicating the
results
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Bias

• Includes
• Personal bias
• Expectancy bias
• Bias could affect the way an experimenter designs
  a study, collects data, or interprets results
• Double-blind studies attempt to control bias
• Must control confounding variables

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Ethics in Research

• American Psychological Association (APA)
• Institutional Review Board (IRB)
• Institutional Animal Care and Use Committee
  (IACUC)

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Basic Ethical Guidelines (APA)

1. Minimize possibility of misleading results
2. Protect participants from harm and discomfort
3. Obtain informed consent
4. Confidentiality concerning participants
5. Only use deception if no better alternative is
   available
6. Fully explain research afterwards

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Types of Psychological Research

• Non-experimental methods include
• Correlational studies relationship, not
  necessarily causation like an experiment can
  show /-
• Surveys behaviors, attitudes, opinions, beliefs
  be careful of biased questions that skew results
  lies
• Naturalistic observation natural environment
  reduce attention drawn no controls
• Longitudinal studies one group followed for
  long period accurate - costly and time
  consuming
• Cross-sectional studies cross section at
  specific time less time - not as
  accurate
• Case studies intensive study useful for rare
  or new interests/findings

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Which Method Would You Use?(experiment,
correlational, survey, case study, naturalistic
observation)

• Determining the favorite food of adolescents
• Determining if frustration causes aggression
• Determining if level of education is associated
  with crime
• Determining how teenagers behave on their first
  date
• Determining why a housewife gave up a flourishing
  career

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Raw Data

• Can be arranged in a summary chart known as a
  frequency distribution
• Shows how frequently each of the various scores
  in a set of data occurs
• We can convert the data into a graph called a
  histogram
• Height of bars indicates the frequency of a group
  of scores
• Continuous data (age, money)

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Describing the Data With Descriptive Statistics

• Descriptive statistics include
• The mean
• The median
• The mode
• The range
• The standard deviation
• The normal distribution

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Correlation

• Correlation A relationship between two
  variables, in which changes in one variable are
  reflected in changes in the other variable
• Correlation coefficient A number between -1 and
  1 expressing the degree of relationship between
  two variables
• Positive, Negative and Zero Correlations
• Positive variables move in same direction
• Example Time studying and test scores
• Negative variables move in opposite directions
• Example Exercise and heart disease
• (-1)Strong ------------(0)---------
  --Strong (1)
• Weak

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Inferential Statistics

• Used to assess whether the results of a study are
  reliable or whether they might be the result of
  chance
• Sampling - random and representative samples
• Statistical significance (plt.05) probability
  that the difference between 2 variables might be
  due to chance is less than 5
• Takes into account sample size, size of
  difference, and standard deviation
• Means there is a meaningful difference between
  groups
• Confident that the difference is real and not due
  to chance!

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Questions Science Cannot Answer

• The scientific method is not appropriate for
  answering questions that cannot be put to an
  objective, empirical test
• Ethics
• Morality
• Religious beliefs
• Preferences