CHAPTER 1 Thinking Critically with Psychological Science
Psychology is a Social Science Again, Psychology is the scientific study of behavior and mental processes Common Sense and Intuition are unreliable – Hindsight Bias/”I-Knew-it-all-along” Phenomenon = “hindsight is 20/20” – Overconfidence
The Scientific Method in Psychology Observe phenomenon Form Hypothesis Make prediction(s) based on the hypothesis Testing/Research – Combat biases by adequately formulating research study and defining the operational definitions of the experiment/study Reject, Revise/Retest or Accept hypothesis (as a Theory) and Report – The new theory should be able to: Organize and link observed facts Be able to be retested (experiment be replicated under similar conditions per the operational definitions) yielding similar results 90% or more of the time Be applied to further knowledge overall/help people!
Descriptive Research Methods (describes behavior but does NOT explain) Case Study – intensive observational study of one or a few individuals for a long time with the aim of making overall generalizations – Strength: can lead to good hypotheses for further study – Weaknesses VERY time consuming Subjects not necessarily representative of the population
Survey – can be given orally or in writing – Strengths Cheaper & quicker to administer Can be given to almost any size of subjects – Weaknesses Can very hard to write effectively (confusing/misleading) People can easily lie/misreport on surveys People can not turn in surveys or refuse to participate Descriptive Research Methods
Naturalistic Observation – researcher watches and records behaviors of subject in their natural environment/setting – Strengths Is a good way to observe subject as they would naturally act Can lead to good hypotheses – Weakness: cannot explain behaviors it can only observe them.
Does behavior change when the subjects know they are being observed? Hawthorne Effect
Descriptive Research Methods (sub-types) Longitudinal Study – one group of subjects is followed and observed (naturalistically, surveyed at different times, etc.) for a long period of time – Strength: can show development over time (stronger than naturalistic observation) of a group – Weakness: VERY time consuming
Descriptive Research Methods (sub-types) Cross-sectional Study – examines a representative cross section of the population at one time (with tests, surveys, observations, etc.)
Correlation Research (shows a relationship among behaviors – no interference) This strategy is useful in determining the relationship of one condition/trait/behavior accompanying another. – Uses a statistical correlation coefficient (ranges from +1 to -1) to determine The strength of co-occurrence How well the existence of one can predict the appearance/disappearance of the other – Correlation coefficient can be calculated and graphically shown through the use of a scatterplot
Sample Scatterplots Perfect positive correlation (+1.00) Perfect negative correlation (-1.00) No relationship (0.00) The more I eat - the more I weigh OR the less I eat – the less I weigh (scores high or low in both) The more I exercise – the less I weigh (scores high in one & low in other) The more I eat – I turn blue EatingEating W e i g h t0
Correlation Research A Main Strength: Correlational Studies combat Illusory (phony) Correlations due to – Superstitions and hearsay – Perception of order in random events The Main Weakness: Correlations CANNOT show causality!!! – Here’s a Good Example: “Data has shown that students who take AP classes in high school do better in college than those who do not take AP classes” – This is an actual statement from the College Board! Possibilities: – Taking AP classes in high school causes students to experience and adjust to the rigors of college-level classes before they enter college. Therefore, they will be more successful in college – Better/smarter students who would have done better in college anyway take more AP classes in high school
Experimental Research (shows cause and effect related to behaviors − interference) A key component of the scientific method Allows study of causation Operational Definitions (it’s like a recipe): – Experimental conditions: Experimental Group(s) – subjects (should be assigned randomly) who will be subjected to the same experimental condition under study Control Group – subjects (should be assigned randomly) who will NOT be subjected to the experimental condition so that the experimental results can be compared with the results of the control group – Can receive a placebo (a harmless/effect-less substance in lieu of real substance) in drug studies, for instance. Usually a sugar pill. Always “people or animals” Paired with independent variable Group that gets placebo (if there is one)
Experimental Research - Experiment Procedure Types: Single Blind Experiment – subjects do not know whether or not they are in the control group or experimental group while the experiment is being conducted Double Blind Experiment – both subjects and researcher do not know which subjects (including themselves, if a subject) are in the control and experimental groups – This eliminates experimenter expectancy effects in the subjects – (Controlling) Variables First of all, the subjects should be selected VERY carefully: – Random sample although they should be of the same “background” conditions – age, sex, medical/psychological condition(s), etc. to maintain internal validity (eliminates confounding variables – risk factors that affect outcome) – Again, subjects should be randomly assigned to experimental group(s) and control group Independent Variable(s) – the manipulated experimental factor in your experiment Dependent Variable – the outcome factor (measure) that should depend on the independent variable Always “things”
Experimental Research Overall goals: Experiment should have – Validity – results should be generalizable to other populations, settings and conditions – The ability to be replicated with the same results (at least 90% of the time)
5 Controls Random Sample Random Assignment Blind Studies Placebo (if drug experiment) Replication
New drug aids memory in Alzheimer patients Select 10 Alzheimer patients from a list (those in odd numbered rooms) at a Assisted Living Home & rate memory on 1-5 scale (Random Sample) Draw names from a hat and put into 2 groups of 5 (Random Assignment) Control Group receives Placebo Experimental Group receives New Drug (Independent Variable) Conduct a Double-Blind Study Measure memory through 1-5 scale and compare to original score (Dependent Variable) Replicate the experiment Confounding Variables?