Basics of Scientific InquiryBasics of Scientific Inquiry

Common sense claimsCommon sense claims

Common sense claims are often hunches based on anecdotal Common sense claims are often hunches based on anecdotal evidence: e.g. most people would not hurt another human evidence: e.g. most people would not hurt another human being just because an authority figure told them too. being just because an authority figure told them too.

– Milgram’s (1966) famous experiment into conformity.Milgram’s (1966) famous experiment into conformity.– Approx 70% of those tested gave ‘electric shocks’ to Approx 70% of those tested gave ‘electric shocks’ to

what they believed was another test subject, at a level what they believed was another test subject, at a level high enough to kill them. high enough to kill them.

– Before carrying out the research, Milgram had asked Before carrying out the research, Milgram had asked other psychologists whether he should go ahead with the other psychologists whether he should go ahead with the experiment. He was told that nearly all participants experiment. He was told that nearly all participants would withdraw before causing any ‘pain.’would withdraw before causing any ‘pain.’

ThreeThree lessons from Milgramlessons from Milgram

• Skepticism is valuable.Skepticism is valuable.

• Careful observation under controlled Careful observation under controlled conditions is very important.conditions is very important.

• Observer expectancy results are real and Observer expectancy results are real and are research cancer. are research cancer.

– Clever Hans wasn’t so clever, after all.Clever Hans wasn’t so clever, after all.

What Is Scientific Inquiry?What Is Scientific Inquiry?

Four goals of scientific inquiry:Four goals of scientific inquiry:• Description (Description (whatwhat happens) happens)• Prediction (Prediction (whenwhen it happens) it happens)• Causal control (Causal control (what causeswhat causes it to happen) it to happen)• Explanation (Explanation (whywhy it happens) it happens)

How would we apply these goals to the study How would we apply these goals to the study of the effects of alcohol intoxication?of the effects of alcohol intoxication?

An open mind and good An open mind and good imagination are not imagination are not

enough. Research in the enough. Research in the psychological sciences psychological sciences

requires a skeptical requires a skeptical attitude and objective attitude and objective

methodologymethodology..

FalsifiabilityFalsifiability

• The case of blood-lettingThe case of blood-letting

• For a theory to be useful, the predictions For a theory to be useful, the predictions drawn from it must be specific.drawn from it must be specific.

– Tell us what will happenTell us what will happen

– Tell us what will not happen Tell us what will not happen

– How would we test for my ability to How would we test for my ability to mind read?mind read?

The Bottom LineThe Bottom Line

• Progress occurs in science when a Progress occurs in science when a theory does not predict theory does not predict everythingeverything..

• Rather, science benefits from Rather, science benefits from specific predictions about specific predictions about phenomena, made in advance.phenomena, made in advance.

• Falsifiability is liberating – making Falsifiability is liberating – making mistakes furthers progressmistakes furthers progress

Falsifiable or Unfalsifiable?Falsifiable or Unfalsifiable?• Pepsi tastes better than Coca ColaPepsi tastes better than Coca Cola

• Psychics can speak to the deadPsychics can speak to the dead

• Aliens abduct us, do medical experiments on us Aliens abduct us, do medical experiments on us and then return us, leaving no evidenceand then return us, leaving no evidence

•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

PseudosciencePseudoscience

The Nature of ScienceThe Nature of Science

– OrderOrder: there are regular patterns in events: there are regular patterns in events

– DeterminismDeterminism: events have identifiable : events have identifiable causescauses

– EmpiricismEmpiricism: theories should be based on : theories should be based on publicly available evidence gathered publicly available evidence gathered through objective observationthrough objective observation

– ParsimonyParsimony: explanations should explain as : explanations should explain as much as possible as simply as possiblemuch as possible as simply as possible

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.

Ockham's RazorOckham's Razor

The Empirical ProcessThe Empirical Process

Building a Psychological ScienceBuilding a Psychological Science

• Facts: Facts: – objective statement, based on direct observation, objective statement, based on direct observation,

reasonable people agree withreasonable people agree with

• Theories:Theories:– Interrelated set of concepts designed to explain Interrelated set of concepts designed to explain

existing facts & generate new predictionsexisting facts & generate new predictions

• Hypotheses & Specific Predictions:Hypotheses & Specific Predictions:– Predictions about new facts based on the theoryPredictions about new facts based on the theory

The Methods of Psychological ScienceThe Methods of Psychological Science

An Experiment Involves An Experiment Involves Manipulating ConditionsManipulating Conditions

• Manipulating independent variables and Manipulating independent variables and measuring dependent variables helps to measuring dependent variables helps to establish causal relationshipsestablish causal relationships

• Random assignment helps create equivalent Random assignment helps create equivalent groupsgroups

Types of ReasoningTypes of Reasoning

Deductive ResearchDeductive Research

CO NFIRM AT ION- te s tin g o f H 1 , accep t H 1 o r re jec t to N u ll H 0

O BSERVAT O NS- th a t a dd ress yo ur H 1

HYPO THESIS- to te st

T HEO RYY o ur top ic o f in te re st

A top down approach

GENERAL 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).

A bottom up approach A bottom up approach

GENERALGENERAL SPECIFIC SPECIFIC

• Inductive process-Inductive process- Reasoning Reasoning from particular to general E.g. from particular to general E.g. Scientists may observe instances Scientists may observe instances of a natural phenomenon and of a natural phenomenon and derive a general law (inductive)derive a general law (inductive)

Inductive ResearchInductive Research

DEVELOPM ENT OF THEORY

HYPOTHESIS FORM ULATION

DETECTION OF REGULARIT IES

OBSERVATIONS

Inductive or Deductive?Inductive or Deductive?

• Dan is a liar so I predict that the next thing he Dan is a liar so I predict that the next thing he says will be a liesays will be a lie

• Bubba has seen his puppy gnaw on shoes so he Bubba has seen his puppy gnaw on shoes so he predicts that puppies always gnaw on shoespredicts that puppies always gnaw on shoes

• Robins have nested under Ray’s carport for 3 Robins have nested under Ray’s carport for 3 years. He expects that they will nest there again years. He expects that they will nest there again this year.this year.

• The gene for blue skin in fish also codes for The gene for blue skin in fish also codes for aggression so Jane will not put her blue fish in aggression so Jane will not put her blue fish in with Elaine’s red fish.with Elaine’s red fish.

The ExperimentThe Experiment

Independent Variables are Independent Variables are Manipulated by ExperimentersManipulated by Experimenters

• Experimenter controlExperimenter control is the central feature is the central feature of IV’sof IV’s

• IV’s are IV’s are NOTNOT free to vary; instead, they free to vary; instead, they are fixed by designare fixed by design

Dependent Variables are Dependent Variables are Measured in Relation to IVsMeasured in Relation to IVs

• DV’s are said to DV’s are said to dependdepend on, be on, be effectseffects of, or be of, or be causedcaused by IVs by IVs

• DV in alcohol intoxication study?DV in alcohol intoxication study?

Identify the IV and DVIdentify the IV and DV

• Jack does an experiment to determine whether Jack does an experiment to determine whether alcohol makes fish more aggressivealcohol makes fish more aggressive

• Jane puts more water in the dough of her bread in Jane puts more water in the dough of her bread in order to make it rise betterorder to make it rise better

• Martha gives her crying baby a popsicle because Martha gives her crying baby a popsicle because she thinks she may be teethingshe thinks she may be teething

• Dr. Smith shows people violent movies and Dr. Smith shows people violent movies and measures how quickly they eat a meal afterwardmeasures how quickly they eat a meal afterward

• Wanda puts one orchid in the sun and one in the Wanda puts one orchid in the sun and one in the shade because she wants to decrease growing timeshade because she wants to decrease growing time

An Experiment Involves An Experiment Involves Manipulating ConditionsManipulating Conditions

• Manipulating independent variables and Manipulating independent variables and measuring dependent variables helps to measuring dependent variables helps to establish causal relationshipsestablish causal relationships

• Random assignment helps create Random assignment helps create equivalent groupsequivalent groups

List of Core Features of List of Core Features of Experimental Methods:Experimental Methods:

• Independent variables (IV’s)Independent variables (IV’s)• Dependent variables (DV’s)Dependent variables (DV’s)• Random sampling from representative Random sampling from representative

populationspopulations• Random assignment to conditions or Random assignment to conditions or

treatmentstreatments• Efforts to “control” or minimize Efforts to “control” or minimize

extraneous/irrelevant factorsextraneous/irrelevant factors

Operational DefinitionOperational Definition

• The quantification of a variable that The quantification of a variable that allows it to be measuredallows it to be measured

• Concepts in scientific theories must in Concepts in scientific theories must in some way be grounded in, or linked to, some way be grounded in, or linked to, observable events that can be measuredobservable events that can be measured

• Preexisting bias problemPreexisting bias problem

Class ActivityClass Activity

James RandiJames Randi

• The Amazing RandiThe Amazing Randi

• Paranormal 1 million dollar Paranormal 1 million dollar challengechallenge

• http://www.youtube.com/watch?http://www.youtube.com/watch?v=NzwwMmNRIVcv=NzwwMmNRIVc