Basics of Scientific Inquiry Common sense claims Common sense claims are often hunches based on anecdotal evidence e g most people would not hurt another human being just because an authority figure told them too Milgram s 1966 famous experiment into conformity Approx 70 of those tested gave electric shocks to what they believed was another test subject at a level high enough to kill them Before carrying out the research Milgram had asked other psychologists whether he should go ahead with the experiment He was told that nearly all participants would withdraw before causing any pain Three lessons from Milgram Skepticism is valuable Careful observation under controlled conditions is very important Observer expectancy results are real and are research cancer Clever Hans wasn t so clever after all What Is Scientific Inquiry Four goals of scientific inquiry Description what happens Prediction when it happens Causal control what causes it to happen Explanation why it happens How would we apply these goals to the study of the effects of alcohol intoxication An open mind and good imagination are not enough Research in the psychological sciences requires a skeptical attitude and objective methodology Falsifiability The case of blood letting For a theory to be useful the predictions drawn from it must be specific Tell us what will happen Tell us what will not happen How would we test for my ability to mind read The Bottom Line Progress occurs in science when a theory does not predict everything Rather science benefits from specific predictions about phenomena made in advance Falsifiability is liberating making mistakes furthers progress Falsifiable or Unfalsifiable Pepsi tastes better than Coca Cola Psychics can speak to the dead Aliens abduct us do medical experiments on us and then return us leaving no evidence Pseudoscience A theory with the empirical trappings of real science including a system of theoretical concepts and a wealth of corroborating evidence But a pseudo science has built in defense mechanisms against possible refutation The Freudian theory provides an interpretation for every conceivable symptom of the patient Its predictions therefore can never be refuted http www youtube com watch v IWE5N8z2Aa4 The Nature of Science Order there are regular patterns in events Determinism events have identifiable causes Empiricism theories should be based on publicly available evidence gathered through objective observation Parsimony explanations should explain as much as possible as simply as possible Ockham s Razor A rule in science and philosophy stating that entities should not be multiplied needlessly This rule is interpreted to mean that the simplest of two or more competing theories is preferable and that an explanation for unknown phenomena should first be attempted in terms of what is already known Also called law of parsimony The Empirical Process Building a Psychological Science Facts objective statement based on direct observation reasonable people agree with Theories Interrelated set of concepts designed to explain existing facts generate new predictions Hypotheses Specific Predictions Predictions about new facts based on the theory The Methods of Psychological Science An Experiment Involves Manipulating Conditions Manipulating independent variables and measuring dependent variables helps to establish causal relationships Random assignment helps create equivalent groups Types of Reasoning Deductive Research A top down approach GENERAL THEORY Y o u r t o p i c o f in t e r e s t SPECIFIC IF All oranges are fruit and all fruit grows on trees THEN oranges grow on trees Deductive process Reasoning from general to particular E g Start with a theory look for instances that confirm this deduction H Y P O T H E S IS to te s t OBSERVATONS th a t a d d r e s s y o u r H 1 C O N F IR M A T IO N t e s t i n g o f H 1 a c c e p t H 1 o r r e j e c t t o N u ll H 0 Inductive Research A bottom up approach GENERAL SPECIFIC Inductive process Reasoning from particular to general E g Scientists may observe instances of a natural phenomenon and derive a general law inductive O B S E R V A T IO N S D E T E C T IO N O F R E G U L A R IT IE S H Y P O T H E S IS F O R M U L A T IO N DEVELO PM ENT O F THEO RY Inductive or Deductive Dan is a liar so I predict that the next thing he says will be a lie Bubba has seen his puppy gnaw on shoes so he predicts that puppies always gnaw on shoes Robins have nested under Ray s carport for 3 years He expects that they will nest there again this year The gene for blue skin in fish also codes for aggression so Jane will not put her blue fish in with Elaine s red fish The Experiment Independent Variables are Manipulated by Experimenters Experimenter control is the central feature of IV s IV s are NOT free to vary instead they are fixed by design Dependent Variables are Measured in Relation to IVs DV s are said to depend on be effects of or be caused by IVs DV in alcohol intoxication study Identify the IV and DV Jack does an experiment to determine whether alcohol makes fish more aggressive Jane puts more water in the dough of her bread in order to make it rise better Martha gives her crying baby a popsicle because she thinks she may be teething Dr Smith shows people violent movies and measures how quickly they eat a meal afterward Wanda puts one orchid in the sun and one in the shade because she wants to decrease growing time An Experiment Involves Manipulating Conditions Manipulating independent variables and measuring dependent variables helps to establish causal relationships Random assignment helps create equivalent groups List of Core Features of Experimental Methods Independent variables IV s Dependent variables DV s Random sampling from representative populations Random assignment to conditions or treatments Efforts to control or minimize extraneous irrelevant factors Operational Definition The quantification of a variable that allows it to be measured Concepts in scientific theories must in some way be grounded in or linked to observable events that can be measured Preexisting bias problem Class Activity James Randi The Amazing Randi Paranormal 1 million dollar challenge http www youtube com watch v NzwwMmNRIVc
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