1. Thinking Critically with Psychological Science
Chapter 1

2. The Scientific Attitude
To sift reality from fantasy
requires a scientific attitude.
Researchers must be
curiously skeptical and yet
humble at the same time!
Limits of Intuition & Common Sense
Hindsight Bias – “Knew it all along”
Overconfidence – We tend to think we know more than we do.
False Consensus Effect – believing that everyone agrees with our line of thinking
Promotes critical thinking – don’t accept things at face value!
Asks why – Have you ever wondered, “What makes someone a morning person?

3. Research Strategies
Population
Sampling

4. Descriptive Research Methods
Descriptive Methods are used to observe and record behavior only
The Case Study – an extremely detailed study on one or more individuals in order to make generalizations about others. Sometimes called an interview study.

5. Descriptive Research Methods
Survey
Naturalistic Observation

6. Perspective Depression Overeating Behavioral Biological Cognitive
Learned helplessness – receiving constant negative feedback from others causes you to feel this way all the time
Parents told the child to clear their plate before they could have dessert – now they do not notice internal cues about hungry
Biological
Cognitive
Humanistic
Psychodynamic
Social

7. Linked with lower levels of serotonin
Perspective
Depression
Overeating
Behavioral
Learned helplessness – receiving constant negative feedback from others causes you to feel this way all the time
Parents told the child to clear their plate before they could have dessert – now they do not notice internal cues about hungry
Biological
Linked with lower levels of serotonin
Eating carbohydrates can cause a release of serotonin which causes a pleasure – also, lesions on ventromedial hypothalamus have been linked to overeating
Cognitive
Humanistic
Psychodynamic
Social

8. Correlation
Describing behavior is the first step toward predicting it. When surveys and naturalistic observations reveal that one trait or behavior accompanies another, we say the two correlate.
Correlation reveals how closely the two things link together and how well it predicts the other.

9. Correlation
Positive Correlation: score between 0 & +1. The two things either increase or decrease together (direct relationship).
Negative Correlation: scored with a negative (-) sign; means there is an inverse relationship. As one thing increases the other decreases.
Correlation Coefficient – a statistical measure of the extent to which 2 factors vary together and thus how well either factor predicts the other
+ or – indicates the direction of the relationship
0.00 to 1.00 indicates the strength of the relationship
r= +.68

10. Correlation
Illusory Correlation: statistics can help us see what the naked eye sometimes misses. Correlations not only make visible relationships that we might otherwise miss, they also restrain our “seeing” nonexistent relationships.
We pay attention to sequence, but it may not be a correlation. Bizarre events happen. Correlation Does Not Prove Causation!

11. Research Strategies
Experiment – the investigator manipulates one or more factors (independent variables) to observe their effect on some behavior or mental process (the dependent variable) while controlling other relevant factors.
Random selection of participants
Random assignment of groups/conditions

12. Experimentation
Independent variable: the experimental factor you manipulate; the treatment itself.
Example: Music, medication
Dependent variable: the behavior measured; the factor that might be affected by changes in the independent variable.
Example: Behavior on a scale 1-5 (for best results make the DV quantitative)

13. Experimentation
Experimental condition/group: The condition that exposes subjects to one version of the independent variable.
Control condition/group: A condition identical to the experimental one, except the independent variable has a different value, such as zero. They could be given a placebo depending on the nature of experiment.

14. Common Flaws in Research
Sampling Bias
exists when a sample is not representative of the population
Placebo Effects
Experimental results caused by expectations alone
Participant Bias
a tendency for participants to respond in a certain way because they know they are being observed (Hawthorne Effect) or they believe they know what the researcher wants.
Researcher Bias
occurs when a researcher’s expectations or preferences about the outcome of a study influence the results obtained.
Confounding Variables…

15. Descriptive Statistics: Central Tendencies
Median: is the ½ mark; half of the scores fall above and half fall below.
Mode: the most frequently occurring score in a distribution
Mean: the arithmetic average of a distribution which is obtained by adding the scores and then dividing by the number of scores.
Remember, there may be a couple of high or low scores interfering with the data.

16. Measures of Variance Range – uses the high and low extremes
Standard deviation – a computed measure of how much scores vary around the mean score; it gauges whether scores are packed together or dispered

17. Descriptive Statistics
Normal curve is a graph of frequency distribution shaped like a symmetrical, bell-shaped curve; a graph of normal distribution.
In a normal distribution, about 68% of the scores are within one standard deviation of the mean and about 95% of the scores are within two standards deviations of the mean.

18. Descriptive Statistics
In a normal distribution, the median is equivalent to the mean.
In a positively skewed distribution, the mean is higher than the median.
In a negatively skewed distribution, the median is higher than the mean.
Positive negative

19. Experiments on People
In the past, researchers did not have mandated guidelines when doing experiments, and some would use experimental procedures that were not ethical.
Ethical principles developed by the APA urge investigators to:
Obtain the informed consent of potential participants.
Protect them from harm and discomfort.
Treat information about individuals confidentially.
Fully explain the research afterward (debrief).
Do not be deceitful.

20. Experimentation on Animals
Animal experiments have led to many treatments for humans. They have also led to heated debates. Ethical guidelines are in place for the care and justified use of animals.
The APA guidelines mandate ensuring the “comfort, health, and humane treatment” of animals, and of minimizing
“infection, illness, and pain
of animal subjects.”

21. Key Ethics Principles to understand:
Informed consent – they must be given a statement that informs them of procedures, risks, benefits, and the right of the participant not to participate or to withdraw from the study without penalty
Deception – they cannot be deceived about significant aspects that would affect their willingness to participate
Debriefing – after the participant finishes, they are told of the nature of the results and conclusions