Myers' Psychology for AP Second Edition Unit 2: Research Methods Thinking Critically With Psychological Science 

Module 4: The Need for Psychological Science 

Did We Know It All Along? Hindsight Bias 

• History may seem like inevitable events, however the future is unknown. You do not say "Today starts the 100 years war" because you have no idea how long the war will last. You don't even know if it will be considered a war. This common act is known as the hindsight bias 
• When two opposing views feel like they both make sense there is an error in recollections and explanations. Psychological research is needed to try and understand why both views can be right. Why one person may lean one way in opinion rather than another 
• Hindsight bias studies have been done in both children and adults
• Our intuition is often right but occasionally is wrong. Intuitions is typically "made" through countless casual observations 

Overconfidence

• Humans tend to think they know more than they actually do because they are more confident than correct
• Knowing answers also makes a person more confident
• This overconfidence can be used to predict social behavior and its outcomes. However, they are usually wrong about 60% of the time 

Perceiving Order in Random Events 

• Humans are constantly trying to make sense of the world. As they do this they often find patterns because random occurrences often don't look random 
• Using the example of a coin flip to show that there is no way to know if the coin will be heads or tails. 
• Despite the pattern, the outcome of one event gives no clue to the outcome of the next 

The Scientific Attitude: Curious, Skeptical, and Humble 

• Human have passion in the form of curiosity. They want to explore and understand the world around them. Unfortunately, some questions cannot be answered through science, such as "what happens after death?" Other questions can be answered when put to the test. Observations can lead to support for the predictions 
• Science is often used to determine reality from fantasy and sense from nonsense. Scientists are skeptical of what is being asked, but they are open to the possibility of it working. They begin by asking two questions; "What do you mean?" and "How do you know?" The answers to these questions are then tested to determine if it matches the facts. 
• This attitude brings humility to the world. An awareness of vulnerability to error and openness to new perspectives. 
• Combining curiosity, skepticism, and humility allow psychologists to check and recheck their own and their peers findings. 

Critical Thinking

• The scientific attitude allows for critical thinking. Critical thinking leads to constantly asking questions about the world around us. But it also asks for evidence to answer these questions. Psychologists then have to ask if the evidence is from a credible source and looking at the topic from multiple perspectives 
• Many of the answers to the questions psychologists ask are surprising. The outcomes they receive are not the results they had predicted 
• Answers also can debunk what was thought of by previous generations 

Module 5: The Scientific Method and Description 

The Scientific Method 

• In science, theories explain behaviors/events by giving ideas that organize what has been observed. Organizing these isolated facts helps to simplify the theory. Linking facts with other principles leads to a useful summary. 
• A good theory will produce testable predictions. These predictions are called hypotheses 
• The results of an experiment will conform the theory or reject it. If the theory is rejected, scientists will revise it and determine where they were flawed 
• Theories can bring bias into our observations. To limit this bias, scientists use operational definitions. This means they use exact wording in their experiments. Instead of saying "sleep deprived" they will say "X hour less." They use this because other scientists may have a different idea on what hours are considered sleep deprived. Therefore, if another scientist wanted to complete the experiment they would not be able to replicate it. 
• Descriptive methods describe behaviors. To use descriptive methods you can use case studies, surveys, or observations. 
• Correlation methods associate different variables 
• Experimental methods manipulate the variables in order to discover their effects  

Description 

• Psychologists observe and describe people and draw conclusions about why they act the way they do. They do this through case studies, naturalistic observation, and surveys and interviews. 

The Case Study: 

• Case studies are used to examine one individual (or group) in depth. Psychologists hope to reveal things that are true to all of us through this individual 
• Examples of case studies: Jean Piaget teaching about children's thinking 
• However, individual case studies can be misleading if the person is atypical. This can lead to unrepresentative information and false conclusions
• Stories move us and are often remembered more, but stories are misleading. This is because an anecdote is not evidence. A one time story does not account for all of the other possibilities 
• Case studies do NOT explain behavior, but describe it 
• Case studies are a good form of research, but they also must be proven with other research methods 

Naturalistic Observation: 

• Naturalistic observation records behavior in natural environments. This research is conducted by observing chimpanzees, videotaping parent-child interactions, and analyzing student self-seating charts in a cafeteria 
• Naturalistic observation does NOT explain behavior, but describes it 
• Naturalistic observation has often been used to understand how animals think, speak to each other, and their emotions
• Example: Humans laugh more in social situations then they do when they are alone 
• Naturalistic observation gives a look into everyday life without controlling any of the variables that can influence behavior 

The Survey: 

• Surveys look at many cases but they do not look at the cases in depth 
• Researchers want estimates when they conduct surveys 
• Answers to questions often depend on how the question is worded 

Wording Effects: 

• Wording can change the way the public answers a question 
• A more positive response is given from "help those in need" than "welfare"
• Keeping the questions simple also can give different results than questions that contain very complex wording 

Random Sampling: 

• Sampling bias is very common and the best way to avoid it is through a representative sample 
• However, it is sometimes very difficult to get a representative sample. In these cases, random sampling from the total population is needed 
• Large representative samples are better than small ones 
• A small representative sample is better than a large unrepresentative sample 

Module 6: Correlation and Experimentation 

Correlation 

• When one trait or behavior is related to another, this is called a correlation 
• We can use statistics to figure out how closely two things vary together. Scatterplots are often used to determine this
• The correlation of a scatterplot is positive if the two variables rise and/or fall together 
• The correlation is negative if one variable goes up as the other variable goes down 
• Correlation can also have no relationship if the dots really are scattered with no pattern  
• The closer the correlation is to -1 or +1, the stronger the correlation is 

Correlation and Causation: 

• Correlations allows us to predict future outcomes
• Correlation can indicate the POSSIBILITY if a cause-effect relationship  
• However, association does not prove causation 

Illusory Correlations: 

• A perceived but nonexistent correlation is called an illusory correlation 
• When people believe there is a relationship between two things, they notice and recall instances to prove their point 
• Illusory correlation explains many superstitious beliefs because people notice the one time things line up versus the hundreds of times they don't
• Often times people forget that random coincidences are in fact, random. This causes us to see patterns that are not actually there  

Experimentation

• Experiments are held to confirm or deny certain beliefs
• They are conducted by isolating one or more variables
• Variables of interest can be manipulated or other controlling variables can be held constant 
• The experimental group is tested on while the control group is not. Scientists can then compare the two groups 
• Random assignment is done so that there is an accurate representative for both groups 
• Scientists also try to make sure the groups are very similar. This way, after the experiment is over, any differences can be seen as a result of the experiment and not preexisting conditions 
• No single experiment is conclusive. It must be run numerous times to see if the same results occur 
• Correlation studies happen naturally where as experiments manipulate variables to have an effect 
• Often in drug testing, both the patient and doctor are unaware if they are receiving real medication. This is known as a double-blind procedure. When a patient believes they got the real thing, there is often a boost in spirits and relief in symptoms of sickness 
• Getting better because you thought you received medication is called the placebo effect 

Independent and Dependent Variables: 

• A variable is anything that can vary 
• Independent variables can vary independently from other factors 
• Independent variables are manipulated 
• Factors that can influence the result of an experiment are called confounding variables 
• Dependent variables vary depending on what occurs during the experiment 
• Dependent variables are measured 
• Experiments are designed with validity. Meaning it will test what it is supposed to test and nothing else  

Module 7: Statistical Reasoning in Everyday Life

The Need for Statistics 

• Many people use off-the-top-of-their-head estimates that are often pinned as facts. These inaccurate numbers can mislead the public on various topics 
• It is also important for people to understand numbers in statistics. If there are 10/100 blood clots everyday and there is a 100% increase, this does not mean everyone will get a blood clot. But it does mean the number doubled from 10/100 to 20/100.  

Descriptive Statistics 

• After data is gathered, scientists organize that data. They often use bar graphs, also called histograms, to display their data 

Measures of Central Tendency: 

• Scientists will summarize their data using measures of central tendency. This is a single score that represents a whole set of scores
• The mode is the most frequently occurring score 
• The average of the scores is called the mean 
• The median is the midpoint of the scores 
• In some cases, the mean, median, and mode are the same number 
• Sometimes, data can be skewed because of a few outlier numbers 

Measures of Variation: 

• The variation of data is how similar or diverse the scores are 
• Averages that are taken from scores with low variability are more reliable than averages from scores with high variability 
• The range is the gap between the highest and lowest scores 
• Standard deviation is used to determine how different scores are from the mean 
• A normal curve is usually bell shaped. Most people tend to fall in the middle rather than the extremes 

Inferential Statistics 

When Is an Observed Difference Reliable: 

• Representative samples are better than biased samples. Keep in mind what population a study has sampled 
• Less-variable observations are more reliable than those that use more variables. A 15-20 range is more reliable than a 5-20 range
• More cases are better than few. This can help you confirm the results will be able to repeat 

When Is a Difference Significant: 

• When the averages between two samples is reliable, then it can be confirmed that any differences found are also reliable. And when the differences is large, we can confirm that it reflects a real difference that can be seen across the population 

Module 8: Frequently Asked Questions About Psychology 

Psychology Applied

• An experiments purpose is non to re-create exact behaviors, but rather to test theoretical principles 
• It is in the principles, not the exact findings, that help explain behavior 
• WEIRD stands for Western, Educated, Industrialized, Rich, and Democratic 
• WEIRD cultures are typically the ones that are tested on and give the most data 
• Collectivist cultures emphasize group goals 
• Individualist cultures prioritize individual goals 
• But some similarities can still be found. For example, although all languages are different, they still share principles of grammar and body language 
• Gender also plays a role with differences in behavior 
• Specific attitudes and behaviors may vary based on gender and/or culture, but the processes are the same throughout 

Ethics in Research 

• Psychologists often study animals because humans are also animals. We share a common biology with many species. Psychological, biological, and medical research are often done on animals 
• Many in the animal protection movement protests against testing on animals. They recommend naturalistic observation over experimentation 
• Often arguments arise on if it is okay to value humans over animals. Many point to the fact that humans eat and wear animals everyday. While others say this does not excuse the cruel behavior of some testing sites 
• Animals that bring comfort and companionship, like dogs and cats, are often treated better than cows 
• However, some testing on animals brings positive outcomes for them. Testing shows us which areas they respond to best when touched and what brands of food they like best 
• Most psychological studies are free of stress. They often consist of flashing words and social interactions. However, if a researcher believes deceiving patients will lead to a justifiable end, they may withhold information. Knowing what reaction the psychologist wants from you can cause you to act that way instead of everything be completely natural 
• Ethics committees go over the experiment before it is done. The consent of the patients is also needed before the researchers can begin 
• Psychology can help us reach our goals, but it cannot determine what those goals should be 

Vocabulary: 

Hindsight bias- the tendency to believe, after learning the outcome, that one would have foreseen it. (Also known as the I-knew-it-all-along phenomenon) 

Critical thinking- thinking that does not blindly accept arguments and conclusions. Rather, it examines assumptions, assesses the source, discerns hidden values, evaluates evidence, and assesses conclusions 

Theory- an explanation using an integrated set of principles that organizes observations and predicts behaviors or events

Hypothesis- a testable prediction, often implied by a theory 

Operational definition- a carefully worded statement of the exact procedures (operations) used in a research study. For example, human intelligence may be operationally defined as what an intelligence test measures

Replication- repeating the essence of a research study, usually with different participants in different situations, to see whether the basic finding extends to other participants and circumstances 

Case study- a descriptive technique in which one individual or group is studied in depth in the hope of revealing universal principles  

Naturalistic observation- observing and recording behavior in naturally occurring situations without trying to manipulate and control the situation 

Survey- a technique for ascertaining the self-reported attitudes or behaviors of a particular group, usually by questioning a representative, random sample of the group 

Sampling bias- a flawed sampling process that produces an unrepresentative sample 

Population- all those in a group being studied, from which samples may be drawn. (Note: Except for national studies, this does not refer to a country's whole population) 

Random sample- a sample that fairly represents a population because each member has an equal chance of inclusion 

Correlation- a measure of the extent to which two variables change together, and thus how well either variable predicts the other 

Correlation coefficient- a statistical index of the relationship between two variables (from -1.0 to +1.0) 

Scatterplot- a graphed cluster of dots, each of which represents the values of two variables. The slope of the points suggests the direction of the relationship between the two variables. The amount of scatter suggests the strength of the correlation (little scatter indicates high correlation) 

Illusory correlation- the perception of a relationship where none exists 

Experiment- a research method in which an investigator manipulates one of more factors (independent variables) to observe the effect on some behavior or mental process (the dependent variables). By random assignment of participants, the experiment aims to control other relevant variables 

Experimental group- in an experiment, the group exposed to the treatment, that is, to one version of the independent variable 

Control group- in an experiment, the group not exposed to the treatment; contrasts with the experimental group and serves as a comparison for evaluating the effect of the treatment 

Random assignment- assigning participants to experimental and control groups by chance, thus minimizing preexisting differences between different groups 

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 of a placebo. Commonly used in drug-evaluation studies 

Placebo effect- experimental results caused by expectations alone; any effect on behavior caused by the administration of an inert substance of condition, which the recipient assumes is an active right 

Independent variable- the experimental factor that is manipulated; the variable whose effect is being studied 

Confounding variable- a factor other than the independent variable that might produce an effect in an experiment 

Dependent variable- the outcome factor; the variable that may change in response to manipulations of the independent variable 

Validity- the extent to which a test of experiment measures of predicts what it is supposed to 

Descriptive statistics- numerical data used to measure and describe characteristics of groups. Includes measures of central tendency and measures of variation 

Histogram- a bar graph depicting a frequency distribution 

Mode- the most frequently occurring score(s) in a distribution 

Mean- the arithmetic average of a distribution, obtained by adding the scores and the dividing by the number of scores 

Median- the middle score in a distribution; half the scores are above it and half the scores are below it 

Skewed distribution- a representation of scores that lack symmetry around their average value

Range- the difference between the highest and lowest scores in a distribution 

Standard deviation- a computed measure of how much scores vary around the mean score 

Normal curve (normal distribution)- a symmetrical, bell-shaped curve that describes the distribution of many types of data; most scores fall near the mean (about 68% fall within one standard deviation of it) and fewer and fewer near the extremes 

Inferential statistics- numerical data that allow one to generalize---to infer from sample data the probability of something being true of a population 

Statistical significance- a statistical statement of how likely it is that an obtained result occurred by chance 

Culture- the enduring behaviors, ideas, attitudes, values, and traditions shared by a group of people and transmitted from one generation to the next 

Informed consent- an ethical principle that research participants be told enough to enable them to choose whether they wish to participate

Debriefing- the postexperimental explanation of a study, including its purpose and any deceptions, to its participants