PSYCHOLOGICAL INQUIRY

TYPES OF PSYCHOLOGISTS Research psychologists- conduct research to apply to everyday life Clinical psychologists- study, assess, and treat troubled people Psychiatrists- medical doctors trained to treat mental disorders as well

TROUBLE WITH COMMON SENSE Hindsight Bias The idea that “I knew it all along” Believing you could have known what did happen Overconfidence Believing we are better at determining accurate conclusions than we actually are

WHY IS OVERCONFIDENCE A PROBLEM It reduces our ability to think critically.

SCIENTIFIC METHOD Problem- Define the problem; Ask a question Observation- see what other people have already found out about it Hypothesis- What do you think is going to happen? Experiment- Design a way to test (experiment, survey, case study) the hypothesis Conclusion- What your experiment or study indicates

WAYS TO STUDY PEOPLE Case Study Naturalistic Observation Experiment Survey

CASE STUDY Studying one or more people in depth for a long period of time Example: The marshmallow case study

NATURALISTIC OBSERVATION Watching and observing something in its environment

EXPERIMENT A psych research method intending to prove causation

SURVEY A research method where a group of people is studied by asking them questions

EXPERIMENTS Propose a hypothesis Define the variables Define the groups Test it Revise the hypothesis Variables Independent- the item being altered Dependent- a result of the change Groups Experiment- the group being tested Control- the group used for comparison

LET’S TRY IT A psychiatrist would like to test the hypothesis that a new drug improves memory in high school students. He randomly selects 100 high school students to test the drug on. For 50 of the students, he administers the drug and asks them to memorize a list of random digits. He then tests their memory of the digits. For the remaining 50 students, he administers a placebo and repeats the same memory test. What would indicate that the drug worked?

SO… Hypothesis= Variables Independent= Dependent= Groups Control= Experiment=

ETHICS Moral standards for any study or experiment Dependent on personal moral standards Committees usually decide if an experiment is ethical Why use animals? We are animals Helps us learn about ourselves

SURVEY Determine what you want to study Determine who you want to study Determine how you will get a sample Construct a questionnaire Collect data Analyze data Random- each person has an equal chance of being selected Systematic sampling- choosing every Nth person Convenience- choose people who you can easily get to answer Stratified- choosing people in various sub- categories like males and females

WHICH GRAPH TO USE? Histogram Data is quantitative Looking for number of people that fit into a defined category Examples: How much time do you spend doing homework? How tall are you? What score you got on the last test Scatterplot Data is quantitative Looking for the correlation between two variables Examples: Numbers of hours slept and time spent on homework Size of dog and life span Age and happiness rating

LET’S TRY IT… A psychologist wants to see if there is a correlation between hours spent studying for a test and the grade on the test. He took a random sample of 50 students, and charted their self-reported hours spent studying against their test scores.

SO… What is being studied? Who is being studied? How are they being sampled? What type of graph is needed?

ANALYZING SCATTERPLOTS-CORRELATION Correlation Coefficient- how well two variables are related Number between -1 and 1 The closer it is to 0, the less correlation the data has Positive- as one goes up, so does the other Negative- as one goes up, the other goes down No correlation- no clear pattern

ANALYZING HISTOGRAMS Mean: the average of the data (add up the numbers Median: the middle number of the data Mode: the most frequent number in the data Standard Deviation: a measure of dispersion from the mean (how far away each number is from the average) Try it: Find the mean, median and mode of the following data set 5,6,6,7,8,9,8

ANALYZING HISTOGRAMS Standard Deviation: a measure of dispersion from the mean (how far away each number is from the average) Steps to finding: Find the mean For each number, subtract the mean from the number, then square the results Add all the squares, then divide by one less than the total number of results Finally, take the square root. Try it: 5,6,6,7,8,9,8

BELL CURVES (A.K.A. NORMAL DISTRIBUTION) When a histogram looks like a bell It has a special distribution: % of the data lies within one standard deviation of the mean (34% on either side) 95% of the data lies within two standard deviations of the mean 99.7% of the data lies within three standard deviations of the mean

EXAMPLE- TEST SCORES Students in a psychology class took a test Their scores were normally distributed with a mean of 85 and a standard deviation of 5. Draw a picture of what this would look like What percentage of the scores were between 80 and 90? What percentage of the scores were between 75 and 95?