Thinking Critically With Psychology. The Need for Psychological Science

Thinking Critically With Psychology


The Need for Psychological Science



Did We Know It All Along?

After the first two murders at Virginia Tech, and before the massacre, many people say it was obvious that the university should have locked down campus.

Commonsense describes what has happened after the fact more easily than it predicts what will happen before the fact. This is called the hindsight bias.

Hindsight is 20/20!

A thought experiment: Tell one group of people that “psychologists have found that separation weakens romantic attraction.” Asked to imagine why this is true, what do you suppose people will say?

A thought experiment: Tell one group of people that “psychologists have found that separation weakens romantic attraction.” Asked to imagine why this is true, what do you suppose people will say?

I already knew that! Commonsense! Out of sight, out of mind!

A thought experiment: Tell another group of people that “psychologists have found that separation strengthens romantic attraction.” Asked to imagine why this is true, what will do you suppose people will say?

A thought experiment: Tell another group of people that “psychologists have found that separation strengthens romantic attraction.” Asked to imagine why this is true, what will do you suppose people will say?

I already knew that! Commonsense! Absence makes the heart grow fonder!



Psychology Makes the World a Better Place to Live

The innovation: the lime-green fire truck.

The rationale: perceptual psychologists’ discovery that the human visual system is most sensitive to light with wave lengths between 510 and 570 nm.

400 nm 500 nm 600 nm 700 nm

The result: lime-green fire trucks are more than three times less likely to be in a traffic accident than red fire trucks (Solomon & King, 1995).

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The innovation: the sequential police lineup procedure, in which a witness is shown suspects one at a time instead of all at once (simultaneously).

The rationale: psychologist Gary Wells’ discovery that when shown sequential lineups, people make absolute judgments, which lead to much lower rates of misidentification.

The result: sequential lineups cut eyewitness misidentification in half compared to simultaneous lineups. Fewer innocent people go to jail.

Thinking Critically with Psychology

How Do Psychologists Ask and Answer Questions?

The Scientific Method

Theory – an explanation using an integrated set of principles that organizes observations.

Theory

Hypothesis

Hypothesis – a testable prediction implied by a theory.

Theory

Hypothesis

We might theorize that the cause of depression is low self-esteem—one’s feelings of self-worth.

We might hypothesize that depression and self-esteem will correlate negatively.

We might test this hypothesis by seeing if people who receive a low score for self-esteem tend to receive a high score for depression.

Research Process



Generating a research question

Everyday observation – One source of research questions psychology is simply observing the world around you and asking questions about why people think and behave as they do.

Generating a Research Question

In the 1960s, social psychologists John Darley and Bibb Latane were horrified by the brutal murder of a woman named Kitty Genovese. It was widely reported that dozens of neighbors witnessed or were aware of the attack—but no one helped.



Darley and Latane hypothesized that any given bystander is less likely to give aid to a victim if other bystanders are present. In a series of studies, Darley and Latane found that this is indeed the case.


http://www.youtube.com/watch_popup?v=JcowGVd6GqY&vq=medium





Personal experience – Like you, psychologists want to understand their own tendencies, limitations, and foibles.

http://www.nytimes.com/2014/07/15/science/which-matters-more-talent-or-practice.html?_r=0


Replication – seeing whether a basic finding can be observed again with different participants and under different circumstances.

After the original study of the bystander effect, there were dozens of follow-up studies aimed at answering specific questions about the effect.




Establishing operational definitions

Operational definition – a specific statement of the procedures used to define research variables, so as to allow others to replicate the original observations.

Establishing Operational Definitions

An operational definition of intelligence might be the number correct on tests of verbal, spatial, numerical, and reasoning abilities.

Establishing Operational Definitions



Choosing a research design

Choosing a Research Design

Descriptive

Correlational

Experimental

Lab Field

Methods

SettingThree major types of research designs that psychologists use in their research…


Descriptive Methods

The Case Study – an in depth investigation of a single (or very few) subjects

Through a 30-year case study, Irene Pepperberg concluded that African Grey parrot Alex could name and categorize objects, and comprehend numbers up to six.

The Case Study

http://www.youtube.com/watch?v=7yGOgs_UlEc

Through a series of case studies, often of his own children, Jean Piaget developed an influential theory of cognitive development, which assumes that cognitive functions unfold through a series of distinct stages.

The Case Study

The Case Study

http://www.youtube.com/watch_popup?v=ue8y-JVhjS0&vq=small


Descriptive Methods

The Survey – an investigation of many cases in less depth by asking people to report opinions and behaviors

A technique for ascertaining the self-reported attitudes, opinions or behaviors of people usually done by questioning a representative sample of people—one that accurately portrays the population of interest.

The Survey

The Survey


Descriptive Methods

Naturalistic Observation – recording behavior in its natural environments, and describing it in detail

Primatologist Jane Goodall used naturalistic observation to study chimpanzees. She concluded, “Observations, made in the natural habitat, helped to show that the societies and behavior of animals are far more complex than previously supposed.”

Credit: Delphine Bruyere

Naturalistic Observation

Psychologists have used naturalistic observation to study, effects of social interaction on people’s behavior. One study found that people laugh 30 times more often in social situations than in solitary situations (Provine, 2001).

Naturalistic Observation


Experimental Methods

Purpose is to explore cause and effect by manipulating one or more factors, while holding other factors constant

Variable – anything that can fluctuate. Whether it’s rainy or sunny, warm or cold, or whether a person is male or female, or in a good mood or a bad mood, are all examples.

Independent and Dependent Variables

Independent variable – aspect of the situation or of individuals that can vary independently of other variables. The variables whose effect is being studied.

Online vs. Classroom


Dependent variable – the variable that may change in response to manipulations of the independent variable.


Score on Test

An Example: Does breastfeeding children have an impact on their intelligence later in life?


The independent variable is whether mothers are assigned to an experimental condition in which their children breast feed, or to a control condition in which they feed their children formula.


The dependent variable is the child’s score on an intelligence test at age 8. (This is the measureable aspect of psychological functioning that we think may be influenced by the independent variable.)


Random assignment – assigning participants to experimental and control groups by chance, thus minimizing preexisting differences between the groups that could affect the dependent variable (e.g., SES).

Random Assignment

Cause

Effect

http://www.youtube.com/watch_popup?v=hHHdovKHDNU&vq=medium

Sometimes it’s not possible to conduct an experiment. For example, it isn’t possible to assign a child to be male or female for the purpose of an experiment.

Other times, it’s unethical to conduct an experiment. For example, it would be unethical to assign people to be exposed to polluted air or non-polluted air for the purpose of seeing whether pollution has a negative effect on mental functioning.


Correlational Methods

Purpose is to observe naturally occurring relationships between variables


Correlational Methods

Correlation coefficient – a statistical index (-1 to 1) of the relationship between two variables

Scatterplot – a graphed cluster of dots, each of which represents the values of two variables. The slope of the points suggests the direction of the relationship, while the amount of scatter suggests the strength of the relationship.

Time Spent Studying

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We might theorize that the cause of depression is low self-esteem—one’s feelings of self-worth.

Correlation and Causation

We might hypothesize that depression and self-esteem will correlate negatively.


We might test this hypothesis by seeing if people who receive a low score for self-esteem tend to receive a high score for depression.



Self Esteem

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Correlation does not mean causation!


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Research Ethics

Is it Ethical to Experiment on People?

The Milgram Experiments


Was it that Eichmann and his accomplices in the Holocaust had mutual intent, in at least with regard to the goals of the Holocaust?


“I was just following orders”



http://www.youtube.com/watch?v=yr5cjyokVUs


“I was just following orders”


Research Ethics

(1) Obtain informed consent

(2) Protect them from harm

(3) Maintain confidentiality

(4) Debrief


Research Ethics

Is it Ethical to Experiment on Animals?

Chapter 1 Review

Why do we need psychological science?

How do psychologists ask and answer questions?

What are major steps in the research process?

What are the major research methods that psychologist use?

Chapter 1 Review

Question(s) from textbook on material not covered in class:

Statistical reasoning in everyday life (pp. 36-39)

Documents

Thinking Critically With Psychology. The Need for Psychological Science