1. Hypothesis confirmation bias
A tendency to search for or interpret information in a way that confirms one's preconceptions, leading to statistical errors.
Direct confirmation of previous hypothesis
(vs self-fulfilling hypothesis).
Active search for info and assignment of greater weight to evidence.
A form of selection bias in collecting evidence
Left-handed people are less intelligent than right-handed.
* Gun control supporter reading a crime on the newspaper.

2. 1960, P. WASON EXPERIMENTS WITH RULE DISCOVERY TASK
2-4-6… ?
VIDEO

3. FALSE CONSENSUS BIAS
BELIVE  TRUE
TRUE  OTHER´S BELIEVE
TENDENCY TO BELIEVE THAT OUR OWN FEELINGS AND BEHAVIOURS ARE COMMONLY SHARED (Ross et. al., 1977).
OVERESTIMATION OF OUR VIEW POSITIVELY FEEDS OUR SELF-ESTEEM.
IT MAY JUSTIFY IMPOSITIONS ON OTHERS (Fiske & Taylor, 1991).
Pluralistic ignorance is a situation in which a majority of group members privately reject a norm, but incorrectly assume that most others accept it, and therefore go along with it. This is also described as "no one believes, but everyone thinks that everyone believes".
VIDEO
DON´T BELIVE  NOT TRUE
OTHER´S BELIEVE  TRUE
TRUE I BELIEVE
MONKEY PARADIGM

4. DEFENSIVE ATTRIBUTION
A tendency to blame victims for their misfortune so that one feels less likely to be victimized in a similar way.
Is based on the support of the JWB. (Lerner, 1977)
Examples
Burglary victims blamed for their carelessness of protecting their homes or delegating their home house chores.
Poor people are lazy.
Raped women are provocative.

5. BELIEF PERSEVERANCE EFFECT
Maintaining a belief despite new information that firmly contradicts it.
Such belief may even be strengthened when others attempt to present evidence (backfire effect)
Define human beings as irrational.
The Flat Earth International Conference in Raleigh, North Carolina, attracted hundreds of attendees who believe the shape of the Earth is a disc instead of a sphere.
Festinger et a., 1956, spent time with a cult dating the end of world on December 21, 1954.
Maths gifted students compare mental calculations with the use of malfunctioning calculators in 7 exercises (Timnick, 1982).

6. SOCIAL PERCEPTION HEURISTICS
AVAILABILITY: We estimate the likelihood of an event based on how fast examples appear in mind (e.g. crime index / political elections)  SAMPLE ERROR
REPRESENTATIVENESS: We judge probability of an event/person depending on how close they are to an specific social category:
MIKE is ambitious, argumentative, very smart
Lawyer?
Farmer?
Sample:
30%-70%
Base-rate fallacy
Implicit personality theory

7. ANCHOR-ADJUSTMENT HEURISTIC
When a person uses a specific target number or value as a starting point, known as an anchor, and subsequently adjusts that information until an acceptable value is reached over time.
1x2x3x4x5x6x7x8x9x10 = ? (A)
10x9x8x7x6x5x4x3x2x1 = ? (B)
Film spoilers
Newcomers expectancies (expert speakers)
Judging lazy people
Ethnocentric bias
Depressing states (self-expectancies)

8. INTENTIONALITY AND ATTRIBUTIONS
“I didn´t know the gun was loaded”
Elements of behaviour intentionality (Malle, 2006):
DESIRE: Hope for an outcome
BELIEF: Thoughts of what would happend prior action
INTENTION: The action was meant to occur
AWARENESS: During action performing.
SKILL/ABILITY: To perform the action (e.g. tennis player)
DILEMMA:
Intentional murder or unintentional manslaughter?

9. The role of context in attribution biases
EMOTION = AROUSAL STATE + COGNITION LABELLING
CONDITIONS: AROUSAL INJECTION & “VITAMIN INJECTION”
(ALL with epinephrine)
(Schachter & Singer, 1962)
INFORMED
VITAMIN
(MISINFORMED)
HAPPY-MOOD CONFEDERATE
(internal quick explanation)
Happy behaviour
ANGRY-MOOD CONFEDERATE
Angry behaviour
Environmental clues

10. Overcoming the error TAKE YOUR TIME RETRIEVE EXTERNAL INFORMATION
MOTIVATE TO MAKE CAREFUL ANALYSIS, SP. LEGAL ISSUES
SEARCH FOR REASONS
FEED EMPATHETIC ATTITUDES
SEE OTHER´S BEHAVIOURS LESS STABLE
ROLE SWAPPING TECHNIQUE  THE EMPTY CHAIR
TEST YOUR STARK REALITY

11. Schemas in social perception
Checking
Expecting
BEHAVIOURS
SOCIAL WORLD
INFO
SCHEMAS
Experience
Filters
Visual
Cognitions
Emotions
Persons
Groups
Events
Social issues
Confirming
(Schema-consistent evidence)
Self-fulfilling prophecy
(Rosenthal & Jacobson, 1968)
e.g. Math tests (20%)
Memory
Perception
Attention
Implicit personality theory (Gilovich, 1991)
E.g. Coldness+Strong+Adventurous
A  B
Hypothesis confirmation bias
(Sanbonmatsu et. al. 1993)
E.g. Football match
E.g. Series experiment 2, 4, 6.
Behavioural confirmation
(Snyder, 1992)
e.g. Party bore
A  B
Rules of thumb serving as shortcuts to organise and perceive social world
Heuristics