Chapter 1

The Need for Psychological Science

• Hindsight bias: The tendency to believe, after learning an outcome, that one would have foreseen it

• Judgmental overconfidence: Overconfident of judgments because of bias to seek information to confirm them

Limits of Intuition and Common Sense

• “Intuitive management”: trust statistical predictors

Did We Know It All Along?

• Errors in recollections and explanations

• Common sense describes what has happened easily

  • Can’t predict

• Behavior makes psychology familiar to us

The Case Study

• Case study: Observation technique in which one person is studied in depth in the hope of revealing universal principles

  • Individual cases are atypical, unrepresentative

  • Mistaken judgments and false conclusions

The Survey

• Survey: Technique for ascertaining self-reported attitudes or behaviors of people, usually by questioning a representative, random sample of them

Wording Effects

• Diction is important - connotation

Random Sampling

• False consensus effect: Tendency to overestimate the extent to which others share our beliefs and behaviors

• Population: All the cases in a group, from which samples may be drawn for a study (doesn’t refer to country’s whole population unless national study)

• Random sample: Sample that fairly represents a population because each member has an equal chance of inclusion

• Naturalistic observation: Observing & recording behavior in naturally occurring situations without trying to manipulate and control the situation (cannot explain behaviors)

Correlation

• Scatterplot: Graphed cluster of dots, slope suggests direction of relationship between two variables, amount of scatter suggests strength of correlation

• Correlate: One trait or behavior accompanies another

  • Correlation coefficient: Statistical measure of relationship (how well predicted)

• Usually leave most of variation among individuals unpredicted

Correlation and Causation

• Correlations help us predict & restrain illusions of intuition

• Correlation does not prove causation, indicates possibility of cause-effect relationship

Illusory Correlations

• Illusory Correlation: Perception of a relationship where none exists

  • We are drawn to confirming evidence

  • Prone to perceiving patterns, whether there or not

• Dramatic or unusual events that may be random coincidences

Perceiving Order in Random Events

• Illusory correlations arise from natural eagerness to make sense

• Random sequences often don’t look random

• Given enough random events, something weird will happen

Exploring Cause and Effect

• Isolate cause-and-effect through statistically controlling factors

• Experiment: Research method in which an investigator manipulates one or more factors (independent variables) to observe the effect on some behavior or mental process (dependent variable). By random assignment of participants, experimenter aims to control other relevant factors.

Evaluating Therapies

• Drug treatments & new methods of psychological therapy

  • Double-blind procedure: Participants are blind about treatment - one receives, another gets placebo

• Experimental condition: Condition of experiment that exposes participants to treatment (one version of independent variable)

• Control condition: Condition of experiment that contrasts with experimental condition and serves as a comparison for evaluating effect of treatment

• Random assignment: Assigning participants to experimental and control conditions by chance, minimizing preexisting differences

Independent and Dependent Variables

• Independent Variable: Vary factor independently of other factors

• Dependent Variable: Vary depending on what takes place during experiment

• Both variables are given precise operational definitions

• Specify procedures that manipulate and measure variables

• Level of precision that enables others to repeat the study

Statistical Reasoning

• Organize, summarize, make inferences using statistics

• Doubt big, round, undocumented numbers

Describing Data

• Bar graph: Displays distribution

• Read the scale labels

Measures of Central Tendency

• Mode: Most frequently occurring score in distribution

• Mean: Arithmetic average of distribution

• Median: Middle score in distribution

• Skew can distort the mean

Measures of Variation

• Variation: How similar/diverse scores are

• Low variability is more reliable than high variability

• Range: Gap between lowest and highest scores

• Standard Deviation: How much scores deviate from one another

Making Inferences

• Chance fluctuations in people sampled

• How confident can we infer observed difference accurately estimates?

When is an Observed Difference Reliable?

• Representative samples are better than biased samples

• Less variable observations are more reliable than those more variable

• More cases are better than fewer

When is a Difference Significant?

• When averages from two samples are reliable measures of population, then difference is likely to be reliable as well

• Statistical significance: A statistical statement of how likely it is that an obtained result occurred by chance (less than 5%)

  • Likelihood that a result will happen by chance

  • Doesn’t indicate importance of thee result

Can Lab Experiments Illuminate Everyday Life?

• Experimenter intends lab environment to be simplified reality

• Recreate psychological forces under controlled conditions

• Principle is the same

• Not to recreate exact behaviors of everyday life but to test theoretical principles

Does Behavior Depend on One’s Culture?

• Culture: Enduring behaviors, ideas, attitudes, traditions shared by large group of people and transmitted across generations

• Shared biological heritage is universal

  • Dyslexia is universal

  • Body language communication is universal

  • Loneliness is universal

• Specific attitudes and behaviors vary, underlying processes don’t

Does Behavior Vary With Gender?

• Gender is important to identity and perceptions

• Gender issues permeate psychology

• Biologically same, similarly human

Why Do Psychologists Study Animals?

• How different species learn, think, behave

• Human physiology resembles that of many other animals

• Treatments for human diseases (insulin, vaccines, transplants)

Is It Ethical to Experiment on Animals?

• Animal protection movement protests use of animals in research

• Animals used in research are 1% of animals slaughtered for food

• Answers to ethicality vary by culture

• Compassion for animals vary by perceived similarity to humans & kinship

• Guidelines for humane use of animals

• Animals benefit from research (care and management of habitats)

• Increased empathy and protection for animals

Is It Ethical to Experiment on People?

• Stress or deceive when essential to justifiable end

• Ethical principles developed by American Psychological Association

  • Consent of participants

  • Protect participants from harm and discomfort

  • Treat information about individual participants confidentially

  • Fully explain research afterwards

Is Psychology Free of Value Judgments?

• No

  • Values affect what we study, how we study it, how we interpret results

• Preconceptions bias observations and interpretations (confirmation bias)

• Labeling reveals feelings

Is Psychology Potentially Dangerous?

• Psychology has the power to deceive, purpose is to enlighten

• Enhance learning, creativity, compassion

• Attitudes and behaviors

Chapter 3

nature, nurture, and human diversity

• behavior genetics → effects of genes (nature) & environments (nurture)

  • individual differences in behavior and mental processes

• evolutionary psychology: behaviors, emotions, thinking capacities

• parents, peers, and culture: influence beliefs, values, tastes, language, appearance

behavior genetics: predicting individual differences

• environment: external, nongenetic influences (nutrition - social support)

  • upbringing, culture, current circumstances

• behavior geneticists study differences & weigh effects of heredity & enviro

genes: our codes for life

• cell nuclei contain genetic master code, 46 chromosomes, 23 from mom & dad

  • chromosomes: threadlike structures made of DNA molecules

  • DNA (deoxyribonucleic acid): complex molecule containing genetic info

• genes: biochemical units of heredity that make up chromosomes

  • segment of dna capable of synthesizing a protein

  • human traits influenced by gene complexes

• genome: complete instructions for making an organism, consisting of all the genetic material in organism’s chromosomes

twin studies

• identical twins: twins who develop from a single fertilized egg that splits in two, creating two genetically identical organisms

  • same conception, uterus, birth date, cultural history

• fraternal twins: twins who develop from separate fertilized eggs

• extraversion & neuroticism - identical twins more similar than fraternal

• jim twins identical (personality, intelligence, heart rate, brain waves, intonations)

• separated identical twins had more dissimilar personalities (think, feel, act)

adoption studies

• adoptive families resemble one another in values and attitudes

• adoptees’ traits (outgoingness, agreeableness) more similarities to bio parents

• environmental factors shared by family’s children have virtually no impact on personalities

• adoptive children grow up to be more self-giving and altruistic

temperament studies

• temperament: person’s characteristic emotional reactivity and intensity

• heritability: proportion of variation among individuals we attribute to genes

  • attribute to genetic influence 50% of observed variation among people

  • as environments become more similar, heredity as a source of differences necessarily becomes more important

group differences

• individual differences highly heritable

• nutritional rather than genetic influences explain why today’s adults taller

• heritable individual differences need not imply heritable group differences

nature and nurture

• adaptive capacity

• biological adaptations effect of environment

  • product of biological mechanism

  • shared biology enables developed diversity

• genes not only code for particular proteins, they respond to environments

  • genes are self-regulating

  • gene can code for protein that controls neurotransmitter functions

gene-environment interaction

• environments trigger gene activity

• genetically influenced traits evoke significant responses in others

• select environments well suited to natures

• interactions between genetic predispositions and surrounding environments

  • effect of one factor (environment) depends on another factor (heredity)

• genes affect how people react to and influence us

• biological appearances have social consequences

• nurture via nature

new frontier: molecular genetics

• molecular genetics: identify specific genes influencing behavior, subfield of biology that studies molecular structure and function of genes

• most human traits influenced by teams of genes

• technique for sorting sperm carrying male or female chromosomes → selective abortion

• blueprints for “designer babies” constrained by reality that many genes to influence behavior

• vitro fertilization (‘test-tube’ conception)

parents and peers

• conception (prenatal environment) → family and peer relationships

• nurture begins in the womb

  • embryos receive differing nutrition & exposure to toxic agents

  • richer blood supply

  • more advantageous placement → better nourishment, placental barrier against viruses

• experience affects brain development (cerebral cortex)

• result by puberty → massive loss of unemployed connections (pruning)

• use it or lose it

• neural tissue always changing

• genes dictate overall brain architecture, but experience directs details

• genetic predispositions & social influences shape children’s life

• parental nurture is like nutrition

peers

• subject to group influences (establish ourselves, accepted in groups)

• conformity behavior

• selection effect: kids seek out peers with similar attitudes and interests

• parents more important in education, discipline, responsibility, orderliness, charitableness, interactions with authority

• peers more important for cooperation, “popoularity” styles of interaction