Download 3 types of studies…

AP PSY CH 1:
Critical Thinking &
the Scientific
(aka “empirical”) Method
in Psychology:
1
Unit 1:
Psychology’s History and Approaches
Biopsychosocial approach This integrated viewpoint incorporates various levels of
analysis and offers a more complete picture of any given behavior or mental process.
COPY FOLLOWING onto the 1st page of your R/W Journal & leave there…
Each time you have a R/W Journal assignment, you are put the following
as a heading for your writing (or on 1st line):
Assign. # ____:
Date
Title/Topic of entry (Some will be Review PSY or Review HG)
--------------------------------------------------------------------------------------
• R/W Journal Assignment # 1: Take home, complete, return &
file in date order into your folder.
• APA Scientif. Problem Solvers:
A: Read/Scan pp. 7-8
B: *Scan/Read pp. 3-6
Explain 3 degrees & psy
*Choose the 6 that MOST
career Ex’s for each
appeal to you as a career
1) B.A. or B.S. (Bachelor’s)
*3-4 sentences explaining
2) M.A. or M.S. (Master’s)
what it is & why it
3) Ph. D. (Doctorate)
appeals to you
3
The Need for Psychological Science:
 Psy. uses scientific method to construct theories that
organize observations & imply testable hypotheses
 “Common sense” & intuition?
Often is contradictory & wrong
EX’s: Full moon effect? Absence & love??
 Hind-sight bias is a part of this—”Anybody should have
figured that! …I knew it all along!”
• Can lead us to accept info b/c we are told it is true…
“Sure…I knew that…”
• OR to prove what we already know…
4
Overconfidence:
We all tend to think we are right…after all, if you think
you are wrong, wouldn’t you change to be right??
How long do you think it would take you to unscramble
these 3 words?
Write your estimate down:
WREAT = WATER
ETRYN = ENTRY
GRABE = BARGE
5
• NOW…try these:
EEPCA SONIVI
TETIRB
--Did it take you longer than you thought?
P. 22, side column:
Look at some “expert’s” predictions…
• The Scientific Attitude: “Curious Skeptics”
EX: James Randi the “de-bunker”
But some strange sounding things have proven to be true
(Jefferson, etc., top p. 23)
A true scientific attitude requires healthy skepticism (don’t
just be a jerk) but also humility, b/c we can all be wrong
6
The scientific method
A self-correcting process for asking questions &
observing nature’s answers.
7
Three possible cause-effect relationships
People low in self-esteem are more likely to report depression than are
those high in self-esteem. One possible explanation of this negative
correlation is that a bad self-image causes depressed feelings. But, as the
diagram indicates, other cause-effect relationships are possible.
8
Scientists learned to use checking & re-checking of each
others work to look for mistakes…
Replication (?) & journal submissions (?) are parts
of this process
Critical Thinking: carefully looks at assumptions
(Don’t “ASSUME” b/c you ....?? )
When using critical thinking we don’t blindly accept
Crit. Th. uses scientific evaluations of info
-looks for possible hidden causes (confounding of
variables; extraneous variables)
P. 24: look at the things that psy. has proven & dis-proven
thru sci. research
9
The Scientific Method:
Use of theories,
observation, & experiment to systematically look at info
• Theory: a linking of facts & bridging of basic laws &
principles to organize & predict observations
Theories: NOT just “guesses”:
 are linked by evidence in many areas (principles)…
EX: (p. 24) depression?
• Hypothesis: testable predictions, usually implied by a
theory (“educ. guess”)
10
Important Terms to stress this:
• Theories: a linking of facts & bridging of basic laws
& principles to organize & predict observations
• Theories are NOT just educated guesses…they are
based on previous known, researched knowledge—
principles (“laws” in physics, etc.) that relate to the
topic
This info is tied together to generated ideas that are
interrelated in many ways & seem to be logical
conclusions
11
Hypotheses:
• These are testable predictions, generally based on
theories
The hypothesis is often written as an “If…then…” type of
statement: “If this is true (indep. var.), then this will
happen (dep. var.).”
• Independent var. = cause Dependent var. = effect
12
Operational definition: the way certain terms or
procedures are clearly stated to define or explain what
is being looked at…such as “intelligence…what
exactly do we mean by intelligence in a hypothesis
when looking at this?
• How you measure and consider a phenomenon..
13
Replication:
When another scientist or team of sci. repeat experiment
using much the same techniques & operational
definitions to see if they get the same type of results in
a different setting w/ different researchers
It’s part of the “curiously skeptical” pattern of thought
adds validity (“valid:” is what it says it is..) to psy. science
Scientists constantly check & re-check each other for
errors…
Think of proof-reading your own paper:
Do you sometimes miss errors you should have caught???
14
3 methods of doing research in Psych:
A) Descriptive research (3 types of these)
B) Correlational research
C) Experimental research
FYI: NOTE: If you notice some of these notes are repetitive,
& you are SURE you have them elsewhere, you don’t need
to re-write…Certainly may if you wish to for emphasis…
15
DESCRIPTIVE RESEARCH:
Describes behavior:
3 types
A) case studies
B) naturalistic observation
C) surveys
A) Case Studies: in depth look at 1 individual in hopes of
gaining info about folks in general
EX: See Phineas Gage:
How was he injured?
How was his personality changed?
So Drs. made guesses about what that area of brain
controlled these aspects…
CAUTION! BUT…Watch out of “anecdotal evidence”
EX: “I once knew a guy who….” Does NOT = good sci.
Needs to be followed up carefully to see if it DOES prove true
ALSO: Recent, repetitive, or shocking info tends to stand out
in our memory MORE…& leads us astray!
16
Phineas Gage: (A) What it would have looked
like…&
B
(B) his actual skull
A
17
B) Surveys:
Get sampling of a group & ask ?’s related to area of study
Uses questionnaires
• Surveys are used in both descriptive & correlational
studies
--looks at behaviors & opinions by asking ?’s of
respondents
Be careful with…
1) wording effects: Very important!
Avoid “emotional” words
EX’s: Political surveys often the worst for this!
Use your critical thinking skills when you see these in any
type of study
2) sampling: choosing a smaller group to represent the
group you want to study
18
Avoid false consensus effect! Over-estimating the # of
folks who think or behave the way we do
EX:’s: Again, politics can lead to this…WHY?
Population:
group you want to find info about
Ex’s?
Random sample:
a section of this population
All members of the pop. should have an equal chance of
being chosen for this random sample
EX’s?
Representative sample: Gives a slice of population that
shows various traits w/in the sample
*If you have an unrepresentative sample, can you just add
more people to make it better?
19
*Watch out for you & others over-generalizing:
Just b/c you see 1 person from a group behaving a certain
way does NOT means all members of that group are that
way
BUT…our memory tries to convince us it is true..
Read about Hite Report (top of p. 29)
Problems w/ this study?
C) Naturalistic Observation: watching & recording behaviors
while in natural environment
Could be humans or chimps or birds…
Ex’s:?
*One important part of Nat. Observ. is being unobtrusive—
Why?
20
CORRELATIONAL STUDIES:
When 1 trait accompanies another trait in either a positive or
negative relationship using statistics to describe how
strong—or weak—a relationship is
--how it’s co-related
How strong this relationship is = ability to predict w/ a
correlation
How do we write this relationship? EX: r = +0.45
[strong] (-1.00) ----------0.00---------- (+1.00) [strong]
-- [weak]
Closer to “0.0” = less relationship:
-1.00= perfectly neg. relationship …&
+ 1.00 = perfectly positive one
The strength is represented by r …so r = +0.21 is
not a very strong, but r = -0 .56 is fairly strong
21
-"co-related:“ means have some relationship
EX’s? Studying? TV? GPA?
If 1 goes up, the other goes up, this is a POSITIVE
relationship: they are positively correlated
BUT…If 1 goes down & the other goes up,
these 2 are negatively correlated
Get EX’s of each!
22
So….which is a stronger correlation of the following pairs of
terms (i.e., which is a better predictor)?
i) r = - 0.72 , r = + 0.48
ii) r = + 0.43, r = - 0.11
iii) r = - 0.66 , r = + 0.59
Scatterplots: p. 31, fig. 1.4: each dot = a number for data
(EX: Class scores (score for each kid) on a test)
23
Scatterplots, showing patterns of correlation Correlations can range from
+1.00 (scores on one measure increase in direct proportion to scores on another) to
–1.00 (scores on one measure decrease precisely as scores rise on the other).
24
Scatterplot for height and temperament
This display of data from 20 imagined men
(each represented by a data point) reveals an upward
slope, indicating a positive correlation. The
considerable scatter of the data indicates the correlation
is much lower than +1.0.
25
Imagine the left frame (a) dots = # hrs. studied & more hrs. the higher the
scores go…
--so kid at bottom of the frame didn't study at all… (EX in text)
Kid's score at top of the diagonal line studied a bunch so we see a
positive correlation
Center frame = how grades go down as amt. of time student is absent
from class increases so we see a negative correlation
Frame on right: Would brushing teeth time help psych grade??
So no correlation
26
*V. Important!
Correlation does NOT = Causation!!
Look at p. 32, fig. 1.5..
• That is…there COULD be other things causing something
to happen…..so…NEVER ASSUME !!!
• Could be caused by other (extraneous) variables that come
into play…"a confounding (confusion) of variables“
• Extraneous variables: variables that you don't think about
when you design research that could have caused a
relationship instead of the Indep. Var. you are measuring
Peer reviews (know this term!) look for these “problem
variables”
27
EX: Headline: "Drinking wine will make you rich!"
EX: Fig. 1.6: Which causes what?
???
• Illusory Correlations:
Ideas that we have about 1 thing that causes another (often
"common sense") …but have NO basis in fact
EX’s:
-If you get your head wet & get chilly, will that cause a cold?
-If the weather changes for the worse, does that cause Grandpa's
arthritis to act up?
28
Illusory correlations in everyday life
Consider this question:
If you adopt a baby, does that then increase the
chances of your conceiving a baby?
EVER heard that?
29
Illusory correlation in everyday life
Many people believe infertile couples become more likely to conceive a
child after adopting a baby. This belief arises from their attention being
drawn to such cases. The many couples who adopt without conceiving or
conceive without adopting grab less attention. To determine whether
there actually is a correlation between adoption and conception, we need
data from all four cells in this figure.
Fogg Gilovich, 1991
30
Why do we develop these ideas?
• B/c humans have a "Rage for Order" which makes us see
relationship--i.e., causes—where none exists…it’s same
place superstitions come from
-------------------------------------
Order in Randomness:
• Again, we want to see some reason for
something…is 1 place we get "psychic ability"
The idea that things are left to chance is just too
scary, so we have "good luck" or the “ability” to
throw certain #’s
-but our mind rejects pure chance--we like order!
• Something happens to you & it is a 1 in a BILLION
chance!!!!
Was it destiny??
31
Two random sequences
Your chances of being dealt either of these hands
are precisely the same: 1 in 2,598,960.
Our brain just prefers “good luck…or bad”… “destiny…”
“fate…”
SOME reason that EXPLAINS it!
32
• Just remember… EVEN 1 in a billion
happens 6 X per day, or 2000 times per year.
----------------------------------------------------------------
2 terms you need to know for next section:
Reliability: If you do a test over & over & get same
or v. similar results, it is reliable
-consistent results
Validity: If something measures (or indicates) what
it is meant to measure (or indicate), then it is a
valid measure
-does what is supposed to
Don’t confuse w/ variability…to be covered later….

33
Remember: 3 types of studies…
a) D
b) C
c) Experimentation
Experimentation: Looks at cause & effect b/c it
does control (or "manipulate") variables as much
as possible…
-Use exper. to explain… Best way:
1) manipulate the variable of interest (thing want to
look at…Indep. var.)
2) hold constant--control--other factors
-hard to do w/ humans, but often can find
ways…see study p. 38 w/ babies & formula
 -- It EXPLAINS….correlational PREDICTS
34
Experimentation
Is breast best??
To discern causation, psychologists may randomly assign some
participants to an experimental group, others to a control group.
Measuring the dependent variable (intelligence score in later
childhood) will determine the effect of the independent variable (type
of milk).
35
Control condition: treated JUST like the exper.
condition except it does not get the Ind. Var. as
the exper. cond. does…
-has to take a pill…has to be same color, given
at same time of day, etc.
Random assignment to conditions: each
participant has = chance of being in either the
experimental OR control condition
-helps insure each is as much the same as
possible
36
Independent variable: the thing we are looking at
and are interested in…whether it is medicine,
baby formula, or whatever…what we manipulate…
cause
Dependent variable: part of hypothesis that occurs
if the Indep. Var. is present…. effect
-it is NOT the control condition!
**M/M: We Manipulate independent variable, but
we MEASURE the dependent variable.
*Correlational studies uncover naturally occurring
events…look at relationships that are happening…
But experiments manipulate a factor (variable) to
determine its effect
37
• In “cause & effect” of experiments:
-Cause: independent variable
-Effect: dependent variable
Finding I-V & D-V: “If…then…” : Take what you
want to find out (hypothesis) & write it using
“If…then…” statement: “If this is done…then
this will happen.”
cause…effect…
EX: Are there more admissions to mental
hospitals during the full moon?
What is the Hyp.:? I-V? (If…)
D-V? (then…)
38
Double-blind: neither participant (used to be called
"subject") nor the researcher working w/
participant or materials knows which is real thing
or the control
Placebo effect: researchers' & participants'
enthusiasm can affect results…also the
participant’s belief can affect results b/c just
thinking it will be better can have an effect
Experimental condition: group which gets the
independent variable (like real medicine, etc.)
Dependent variable is the result (effect) from the I-V
Control condition: group that gets placebo or exact
same situation w/o getting the I-V
39
TWO other SPECIAL types of studies,
Used in HUMAN DEVELOPMENT:
(ADDED: 01/24/2013)
The following 2 are ways to use descriptive studies,
correlational studies, and experiments to address human
development (the development of humans over the
lifespan):
Longitudinal studies: study same ppl, following them thru
the years– like at 5 yrs., 10 yrs., 15 years, and 20 yrs. of
age
Cross-sectional: different groups of ppl., of varying ages at
the same point in time—like in the FALL of 2013, choose
20 1st graders (5 yr.-olds), 20 5th graders (10 yr. olds),
20 10th graders (15 yr.olds), and 20 college Juniors (20
yr.olds.)
We WILL study this again in Human Development (Ch 4)
40
------------------------------------------------------------
STATISTICAL REASONING (p. 42):
How researchers who have already gathered
their info then organize, summarize, * make
inferences from it using statistics
Remember:
Design & organize a study
Run the study, collecting data as you go
Organize the data
Analyze the data using
41
1) Describing Your Data: Can organize it into "pictures"
like a bar graph, pie charts, etc. or w/ #’s
A) Measures of Central tendency: mode, mean, & median
figures:
Mode: most frequently occurring #
-this is the simplest way
Mean: what we think of as the "average": add all scores
together & divide by total # of scores
Median: the middle score…aka the 50th percentile…
--list all in # order, get the 1 in the middle, so half = higher,
& half = lower
SEE Fig. 1.12:
*Imagine Bill Gates being in this study!
This shows how these 3 ways of summarizing data (info
gathered) can look differently…
Answer  
42
A skewed distribution
This graphic representation of the distribution of a village’s incomes illustrates
the three measures of central tendency—mode, median, and mean.
Note how just a few high incomes make the mean—the fulcrum point that
balances the incomes above and below—deceptively high.
43
mode = 20 median = 30 mean = 70
Skewed: how 1 method, like median avg., would make the info
NOT truly representative… like B. Gates
You have to look at data patterns & see which would be best
B) Measures of Variation: measuring central tendency can give
good info…but we need to know how much the scores, or
incomes, or whatever, vary
Range: gap between the lowest score & the highest score
Standard deviation: computed measure of how much scores
vary around the mean score… EX: look at the $15,000 income
vs. the $710,000 income…that's a lot…
C) Making Inferences: How can we be sure differences come
from the indep. var.?
-When is observed difference is reliable (gives same results
over & over if re-done)?
44
s  s2
Standard Deviation
Formula:
(Handout: Ch 1 Notebook)
1.Which of the following is a
measure of the degree of
variation among a set of
events?
A) mean B) scatterplot C) standard deviation
D) median E) correlation coefficient
2.On a 10-item test, three students in Professor Hsin's
advanced chemistry seminar received scores of 2, 5, & 8,
respectively. For this distribution of test scores, the
standard deviation is equal to the square root of:
A) 3.
B) 4.
C) 5.
D) 6.
E) 9
45
Common question: “How much do I have to know
about Standard Deviations??”
►Know the definition
►Know that a small range=small s-d…
►And that a large range=large s-d
►Know that a small s-d is better/more reliable than a large
one;
►Know how s-d’s apply to the normal curve
►MIGHT have to calculate a very BASIC S-D (no
calculators allowed!)
46
Real AP Test ?’s On standard deviations
1. If the variance of a set of scores is 100, the standard
deviation will be
A) 5
B) 10
C) 25
D) 50
E) 125
2. For a language test normally distributed scores, the mean
was 70 & the standard deviation was 10. Approximately
what % of test takers scored 60 & above?
A. 16
B. 34
C. 68
D. 84
E. 95
3. Which of the following sets of scores has the greatest SD?
A. 5,7,9,12
D. 50,51,52,53
B. 2,7,9,22
E. 100,101,101,102,103
C. 25,27,29,32
47
Evelyn wants to know how consistent her bowling scores have
been during the past season. Which of the following
measures would be most relevant to this specific concern?
A) mean
B) median
C) scatterplot
D) standard deviation E) correlation coefficient
-------------------------------------------------------------------------------------------------
Differences between 2 samples are least likely to be
statistically significant if:
A) the samples are small & the standard deviations of the
samples are small.
B) the samples are large & the standard deviations of the
samples are large.
C) the samples are small & the standard deviations of the
samples are large.
D) the samples are large & the standard deviations of the
samples are small.
48
49
The normal curve (aka “The Bell Curve”)
Scores on aptitude tests tend to form a normal, or bellshaped, curve. For example,
the Wechsler Adult Intelligence Scale
calls the average score 100.
50
*3 principles for increased reliability (p. 44):
1) representative samples are better
than biased samples
2) Less-variability = more reliability
--relates to S-D (standard deviation)
3) More cases are better than fewer (10
coin tosses = more variability;
100 = less variability, so more
reliability)
51
*When is a difference significant? We can
have confidence in samples that
1) are good samples of pop. we want to study
2) give good, consistent data, not highly
variable data
3) have a lot of samples, not just a few (think
about our coin toss experiment in randomness)
-statistical difference: --BUT…this is not
proof…
Should be _?_ to add confidence in the data
52
Critical Thinking: Read the scale labels
An American truck manufacturer offered graph (a)—with actual
brand names included—to suggest the much greater durability of
its trucks. Note, however, how the apparent difference shrinks as
the vertical scale changes in graph (b).
53
Comparing Research Methods:
A good “quick chart!”
54
Differentiating between Descriptive statistics & Inferential statistics
Descriptive statistics are used to describe something that has
already happened (yesterday's high temperature, the score of last
year's Super Bowl...).
Charts & graphs can be used to display this data to show what was
discovered or seen.
Inferential statistics make an inference (or a prediction) about what
will happen. (tomorrow's high temperature, what will the stock
market do this week...).
The inferences (using info to make an “educated guess”…to read
between the lines) made are usually based on some set of inferential
statistics.
In inferential statistics, you are looking for statistical
significance….meaning the data supports the idea that it most likely
is not just chance.
NOTE: This POPS up on AP & Practice AP exams occasionally!!
• ?’s often asked in PSY:
1) Can lab experiments relate to real life?
--gain general principles--not specific
findings--that help explain behaviors
2) Behavior & culture (ideas, attitudes, behaviors, &
traditions shared by large group & handed down from
generation to gener.): Many attitudes & values
(sex, idea of time, etc.) are strongly
influenced by culture
--but often underlying behavioral processes
are very similar or the same…psy use term
“cross-cultural” vs. culture specific
56
?’s often asked in PSY:
1) Can lab experiments relate to real life?
--gain general principles--not specific findings--that help
explain behaviors
2) Behavior & culture (ideas, attitudes, behaviors, &
traditions shared by large group & handed down from
generation to gener.): Many attitudes & values (sex, idea of
time, etc.) are strongly influenced by culture
--but often underlying behavioral processes are very similar
or the same…psy use term “cross-cultural” vs. culture
specific
3) Behavior & gender: can and does influence
-biology determines sex, culture “bends” the gender
--be careful of exaggerating the differences b/c we tend to
be more the same than different
*Which disorders or problems are related to M’s or F’s? 57
4) Why do psy. study w/ animals? Some want to
see how specific animals behave…like chimps
--but mainly use them for experiments we can’t do
on humans…they aren’t the same as humans, but
do have many of same basic processes & types of
basic learning & emotions EX: fear; drives for
hunger, sex, etc.
5) Ethics & animal research: some say should not
do at all; others say is good way to get info to
help humans w/o using humans for research
--psy. say only 7% of research = animals & 95% of
those = rats, mice, birds, & rabbits
-when animals used, should never cause needless
suffering & should minimize suffering
58
6) Experiments on people:
Psychologists are not allowed to use physical pain, etc.;
should deceive only if must, & then must tell them after
(debriefing)
Ethicical guidelines for APA (Amer. Psychological
Assoc.) & Brit. PA:
a) obtain informed consent from potential participants
b) protect them from harm & discomfort (physical,
mental, emotional)
c) treat info about individual participants (used to be called
“subjects”) w/ confidentiality
d) fully explain research afterward (this is called WHAT??)
e) Research virtually always goes thru “screening
committee” now to make sure nothing is done
unethically
59
7) Is psy free of value judgments?
Any thing done involving humans & their interests will have
some biases & preferences…We see what we expect to see!
But psychologists do try to eliminate as much as possible, &
tries to “catch” each other doing this by sending all
research b4 published to others to read & critique (those
“peer review” committees”)
8) Is psy potentially dangerous? Can it be used to
manipulate people?
All knowledge can be used for good or for evil
Can help by enlightening & gaining understanding:
-crime, family dysfunction, mental illness, prejudice,
overpopulation, war, etc.
BUT can be (and has been) misused, which is why
Psychologists now watch for this carefully
60
QUICK!!
WHAT do you see??
61
WHAT do you think ..
that last slide should help you understand
about our preconceived ideas about what we
observe??
62
Qk. Review: Each is EX: of which??
a.hindsight bias
b.overconfidence
c.false consensus effect
d.anecdotal evidence
e. illusory correlation
1. Joe, whose family lives in GWD, SC, and attends a conservative
Baptist church, believes that almost everyone in the US is a
Republican.
2. When told that she should wear her seat-belt in the car to help reduce
chances of injury, Tina said she wouldn’t wear them because her aunt
“knew a woman who would have died in a fiery crash if she’d had
hers on!”
3. As a 10th grader, Dwayne told his friends he would never move out of
the South when he grew up. When he graduated from USC, he took a
job in New Jersey b/c of the great salary &n benefits.
4. When her husband told her that some investments he made in new
technologies tanked, Lena fumed at her him, “I could have told you
that those stocks were risky!”
5. Darla was wishing Bart would call her...& he did! She began to
believe that if she wished hard enough, her wishes would come true.
63
ACTIVITY: Take each statement & form or
find the following:
a) hypothesis
b) independent var.
c) depend. var.
(NOTE: “If…..then…” statements?)
1. John wants to find out if eating chocolate
will help students remember information
2. Ms. Ackers decided to study whether or
not a clean classroom could influence test
scores.
64
Figure the MEAN, the MODE, and the MEDIAN
for the data set of IQ scores below:
94, 99, 103, 103, 110, 125, 155
What is the range?
Which score most affects the standard deviation?
Why?
65