01 Chapter 1_Thinking Critically With Psychological Science_Student

7/31/2019 01 Chapter 1_Thinking Critically With Psychological Science_Student

1/32


2/32

Goals of PsychologyDescription

Explanation

Prediction

Influence


3/32


4/32

Hindsight Biasis the I-knew-it-all-alongphenomenon.

After learning the outcome of an event, manypeople believe they could have predicted that veryoutcome...

Hindsight Bias


5/32

Sometimes we think we know morethan we actually know.

Overconfidence


6/32

Critical Thinking

Critical thinking doesnot accept argumentsand conclusions blindly.

It examinesassumptions, discernshidden values,evaluates evidence andassesses conclusions.


7/32

Scientific MethodAn approach to knowledge that relies on a

systematic method of testing theories:

1. hypotheses

2. collecting data

3. explaining the data4. revisions


8/32

Scientific Method Theory:

Systematic explanation of a phenomenon

Explanation using a set of principles that organizes andpredicts observations

Hypothesis:

A specific, testable prediction derived from a theory


9/32

Scientific Method

in Action

Develop

Theory DevelopHypotheses

Gather and

analyze data

Draw

Conclusions

ReviseTheory


10/32

Scientific Method Collecting information or gathering data

There are many different ways to collect data

The choice of method depends on the question


11/32

Descriptive Studies: Case Studies Descriptive Studies: Case Studies

Intensive description and analysis of a single individualor just a few individuals Rich description of an individual

Limitations Case exceptions

Decreased generalizability

Observer bias


12/32

Example: Phineas Gage (1948) Railway construction

foreman

Accidental explosionblew his tamping ironthrough his frontal lobe

3 ft 7 inches long

1 - 1/4 inches indiameter (tapered)


13/32

A technique for ascertaining the self-reportedattitudes, opinions or behaviors of peopleusually done by questioning a representative,

random sample of people.

Descriptive Studies: Survey


14/32

Survey issues1. Wording Effect

Wording can change the results of a survey

2. Random Sampling Allows for a representative sample


15/32

How do we sample?

Representative sample

Sample from the population that includes importantsub-groups in the same proportions as in the population

Biased sample

Sample that does not adequately reflect the largerpopulation

Survey issues


16/32

The random sample


17/32

Survey issues3. Desirability Bias

People dont want others to think negatively of them

Can change responses on surveys

4. Inaccurate Introspection

How many times have you done X?


18/32

Descriptive Studies: Observation Types: naturalistic or laboratory

Naturalistic in real (natural) settings

Laboratory in a controlledsetting


19/32

Prediction Using Correlation Correlation a statistical measure of a relationship

How related two traits, behaviors, or events are

Ranges from -1.00 to +1.00

Two things to look at

Strength of the relationship

Direction of the relationship


20/32

Prediction Using Correlation

Correlationcoefficient

Indicates directionof relationship

(positive or negative)

Indicates strengthof relationship(0.00 to 1.00)

r = 0.37+

Correlation Coefficient is astatistical measure of the

relationship between two variables.


21/32

Strength of a Correlation Strength of the relationship

Ignore the sign (+ or -), and just look at the number.

Large numbers mean strong relationship (+.89 or -.89).

Numbers near zero mean weak relationship (.004 = verylittle correlation).


22/32

Direction of a Correlation Positive: as A goes up, B goes up

Negative: as A goes up, B goes down

Positive Negative

A B A B

E.g. Anger and Aggression E.g. Partying and gradesIncreases in Anger = More partying =

Increases in Aggression lower grades


23/32

More correlation examplesAge and foot size: r= +.70

Moderately strong positive correlation

Temperature and freezingdeaths: r= -.95 Strong negative correlation

Money and happiness: r= +.05 Very weak positive correlation

Class attendance and grades: r= +.70


24/32

Perfect positivecorrelation (+1.00)

Scatterplotsare graphs comprised of points that aregenerated by values of two variables. The slope ofthe points depicts the direction, while the amount of

scatter depicts the strength of the relationship.

Scatterplots


25/32

No relationship (0.00)Perfect negative

correlation (-1.00)

The Scatterplot on the left shows a negative correlation,while the one on the right shows no relationship betweenthe two variables.

Scatterplots


26/32

Limitations of CorrelationsCant show causation

Direction: did A B? Or, did B A?

CORRELATION DOES NOT MEAN CAUSATION!

Third variable problem

Relationship between 2 variables may be due to a third,unmeasured variable


27/32

Third Variable FACT!

Higher ice cream sales are positively correlated with increaseddrowning deaths.

Should we ban ice cream???

Probably not

Ice cream sales go up in the summer/hot weather, when morepeople are likely to also swim.


28/32

Explaining with Experiments Experimental designs manipulate variables to assess cause

and effect

Manipulate one variable, and keep all others constant tosee what happens


29/32

Important Terms Used in Experimentation

Independent Variable (IV): variable the experimentermanipulates

Dependent Variable (DV): variable the experimentermeasures to see what changes

Confound: an extra variable that the experimenter didnot measure but that is related to the independent anddependent variables leading to false conclusions


30/32

Experimental Method/terms Experimental group

Group exposed to the IV, or the treatment

Control group

Group and exposed to the same experimentalenvironment but is NOT exposed to the IV

Used for comparison

Random Assignment of participants to groupsensures equality between the groups


31/32

Experimental Methods/Terms Operational definition:

Statement of the procedures used to define researchvariables


32/32

Experimentation: Example

Documents

01 Chapter 1_Thinking Critically With Psychological Science_Student