Chapter One

Thinking Critically With

Psychological Science

IntuitionIntuition• An effortless, immediate, unreasoned

sense of truth

• David Myers- author of our text said “Instinct has the power to hush reason. But when is it safe to go with your gut? Researchers may remain uncertain about the reliability of intuition, but it is a difficult force to deny.”

PitfallsPitfalls of in thinking that make intuition intuition and common senseand common sense untrustworthy: Hindsight bias and overconfidence

• Hindsight Bias: the tendency to believe, after learning an outcome, that one would have foreseen it.

• Have you ever watched Jeopardy with someone, and after the answer is given that person says "I knew that one" or "That was an easy one"?

• Take Ken Jennings…he won 2.5 Million on Jeopardy…but he did have this blooper…

Overconfidence is the tendency to think we know more about an issue than we actually do and to overestimate the accuracy of that knowledge.

Self-Test of OverconfidenceFor each of the following, give a 90% confidence interval (an upper and lower bound). That is to say, you should be confident enough in your interval that you would take a 9:1 bet that the actual number is between the range you give (or take a 1 to 9 bet that the actual number is outside your range). Write down or record what your ranges are before looking at the answers so that you don't cheat.

1.) Martin Luther King's age at death2.) Length of the Nile River (in miles)3.) Number of countries in OPEC4.) Number of books in the Old Testament5.) Diameter of the moon (in miles)6.) Weight of an empty Boeing 747 (in pounds)7.) Year in which Wolfgang Amadeus Mozart was born8.) Gestation period of an Asian elephant (in days)9.) Air distance from London to Tokyo (in miles)10.) Deepest known point in the ocean (in feet)

Answers:1.) 39 Years2.) 4,187 Miles3.) 13 Countries4.) 39 Books5.) 2160 Miles6.) 390,000 Pounds7.) 17568.) 645 Days9.) 5,959 Miles10.) 36,198 Feet

Give yourself a point for each range that contained the actual value. If your confidence in your intervals were really 90%, that means on average at least 9 of your answers should be right. In previous experiments and surveys, this happens about 1% of the time or less. Are you surprised at your result?

Scientific AttitudeScientific AttitudeIs being willing to accept only carefully Is being willing to accept only carefully

and objectively verified facts, and to and objectively verified facts, and to hold a single fact above the authority of hold a single fact above the authority of

the oldest theories. Nothing can be the oldest theories. Nothing can be called scientific that is not based on called scientific that is not based on

such an attitude. such an attitude.

The guide to a scientific attitude is The guide to a scientific attitude is Curiosity, Skepticism, and Humility.Curiosity, Skepticism, and Humility.

Critical ThinkingCritical Thinking

Thinking that does not blindly accept arguments and conclusions. Rather it assumptions, discerns hidden values, evaluates evidence, and assesses conclusions.

Such examples given by the text: Massive losses of brain tissue early in

life may have minimal long term effects.

Scientific MethodScientific Method• Theory- explains a set of principles that

organizes observations and predicts behaviors or events.

• Hypotheses- Educated Guess- the testable predictions often implied by a theory.

• Bias-Particular belief that restrains openness of the scientific method outcomes

• Operational definition- statement of the procedures used to define research variables. (What is the measure of say…anger?Or what is the independent variable or dependent variable)

Scientific MethodScientific Method

• ReplicationReplication-repeating the essence of a research study, usually with different participants in different situations, to see whether the basic finding extends to other participants and circumstances.

What is the importance of theories in Psychology?

• Because they are trying to

• Explain,

• Organize,

• and Predict

• Behavior of the events under the study/research!

The Good Theory has two The Good Theory has two elements:elements:

1. Organizing and linking observed facts

2. Implying hypotheses that offer testable predictions and sometimes practical applications.

Research GoalsResearch Goals

Descriptive Approach to Research-Descriptive Approach to Research-observe, measure, describe.

An exampleAn example:An opinion poll to determine which Presidential candidate people plan to vote for in the next election. Descriptive studies do not seek to measure the effect of a variable; they seek only to describe.

Research Goals

• Correlational Approach to Research-Correlational Approach to Research-two different types of behavior and evaluate the relationship between them.

Example:Example:a study that looked at the proportion of males and females that would purchase either a classical CD or a jazz CD would be studying the relationship between gender and music preference.

Research GoalsResearch Goals

• Experimental Approach to Research-Experimental Approach to Research- investigate cause and effect relationships by manipulating one aspect of the aspect that is thought to produce a change in that particular behavior.

• When using experimental research scientists usually, but not always, conducted in a laboratory. The laboratory environment allows the experimenter to make controlled observations using the steps of the scientific method.

Example of Experimental ResearchExample of Experimental Research1. Theory or research Question- The study is about whether certain environmental conditions improve or adversely affect motor performance. 2. The investigator might give operational definitions to the environmental condition of interest as “background music” and the motor performance as “typing speed.” 3. Next, the investigator proposes an answer to the research question (“What is the relationship between typing speed and background noise?), an answer called a hypothesis. 4.Define Variables: the relationship between two variables, an independent variable (that which the experimenter manipulates—in this case, the background music) and a dependent variable (that which changes as a consequence of manipulation of the independent variable—in this case, the typing speed). The experimenter hypothesizes that “an increase in loudness of background music will produce a decrease in typing speed.”

• subjects would be taken to a laboratory for testing and would use the same typewriters to take the typing tests.

• The experimenter would have to decide whether to use two groups of subjects with comparable typing skills and expose one group to a music loudness level different from that used with the other or sequentially expose the same subjects to music of two loudness levels.

• Each procedure has advantages and disadvantages.

Types of Descriptive ResearchTypes of Descriptive Research

• Case Study-Case Study- An observation technique in which one person is studies in depth in the hope of revealing universal principles

• Ex. Genie, Kitty Genovese, Bystander effect situations.

Types of Descriptive ResearchTypes of Descriptive Research

• SurveySurvey- a technique for ascertaining the self reported attitudes or behaviors of a particular group, usually by questioning a representative, random sample of the group.

• PopulationPopulation- all the cases in a group being studied, from which samples may be drawn.

SurveySurvey

• Wording Effects-Wording Effects- surveyors have to be careful on misleading or misinterpretation of wording.

• Words like usually, often, sometimes, occasionally, seldom, and rarely are "commonly" used in questionnaires, although it is clear that they do not mean the same thing to all people.

SurveySurvey

• Representative Sample- Representative Sample- researcher attempts to select individuals which are representative of a larger population. .

• Truly representative sampling is extremely hard to accomplish, and researchers may dedicate a great deal of time and funding to getting the most representative sample possible.

• Example: How many people in the U.S. sleep with their pets?

• Look for American pet owners, but make sure that you take the information from all over the U.S., Ex. Not just Chicago. Not just Georgia…

SurveySurvey

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

• For example, each name in a telephone book could be numbered sequentially. If the sample size was to include 2,000 people, then 2,000 numbers could be randomly generated by computer or numbers could be picked out of a hat. These numbers could then be matched to names in the telephone book, thereby providing a list of 2,000 people.

Experimentation- Experimentation- a research method in which an investigator manipulates on or more factors to observe

the effect on some behavior or mental process

• Randomly assigning- assigning participants to experimental and control groups by chance, thus minimizing preexisting differences between those assigned to different groups.

• Grouping– Experimental- group that is exposed to the treatment

(to one version of the independent variable)– Control- group that is not exposed to the treatment.

Serves as a comparison for evaluating the effect of the treatment.

• Placebo-(placebo effect) results caused by expectations alone (belief in it). Substance or condition which the recipient assumes is an active agent.

• Double Blind Procedure-Double Blind Procedure- both researcher and participants are ignorant about whether the research participants have received the treatment or a placebo.

Statistical Reasoning in Everyday Life

• Statistics organize, summarize, and make inferences from data.

Three measures of Central Tendency :1. ModeMode- most frequently occurring score in a distribution.2. Mean Mean is the arithmetic average of a distribution. (add scores then divide by number of scores)3.MedianMedian is the middle score in a distribution; half the scores are above it and half are below it.

Two measures of Variation:

1.1. RangeRange (of scores)- gap between the lowest and highest score (this shows only a rough estimate of variation)

2.2. Standard deviationStandard deviation – measures how scores deviate form one another. It better gauges whether scores are packed together or dispersed because it uses information from each score. Many types of scores are distributed alone a bell shaped curve or a normal curvenormal curve.

Dark blue is less than one standard deviation from the mean. For the normal distribution, this accounts for about 68% of the set (dark blue), while two standard deviations from the mean (medium and dark blue) account for about 95%, and three standard deviations (light, medium, and dark blue) account for about 99.7%

Three principles for making generalizations form samples.

1.1. Representative samplesRepresentative samples are better than biased samples. We are particularly prone to over-generalize from vivid cases at the extremes.

2. Less-variable observations are better than those that are more variable. Averages are more reliable when derived from scores with low variability.

3.3. More casesMore cases are better than few. Small samples proved less reliable estimates of the average then do large samples.

How do psychologists decide whether differences are meaningful?• Tests of Statistical significanceStatistical significance

determines whether difference between two groups are reliable. When the averages (mean) of the samples drawn from the groups are reliable and the difference between them is relatively large, we say the difference has statistical significance.

Finding (for example the observed difference betweenFinding (for example the observed difference between the means of two random samples) is the means of two random samples) is

described as statistically significant, when it candescribed as statistically significant, when it can be demonstrated thatbe demonstrated that

the probability of obtaining such a difference by the probability of obtaining such a difference by chance only, is relatively low. In Psychology, and in manychance only, is relatively low. In Psychology, and in many

other domains, it is customary to describe other domains, it is customary to describe one's finding as statisticallyone's finding as statistically

significant, when the obtained result is among those that (theoretically) significant, when the obtained result is among those that (theoretically) would occur no more than 5 out of 100 times when would occur no more than 5 out of 100 times when the only factors operating are the chance variationsthe only factors operating are the chance variations that occur whenever random samples are drawn. that occur whenever random samples are drawn.

                                                                                                                                                                                                                                                

Value of simplified Lab conditions

• Experimenter intends the lab experiment to be a simplified reality, one in which important features can be simulated and controlled.

• The experiment’s purpose is not to recreate the exact behaviors of everyday life, but to test theoretical principles. It is the resulting principles not the specific findings- that help explain everyday behavior.

Can psychological research be generalized across culture and

genders?• Culture shapes our specific attitudes and

behaviors, the principles that underlie them vary much less.– Biological heritage– Studying gender differences can help

prevent conflict or misunderstandings in daily life.

– Men and women are overwhelmingly similar, biologically and psychologically

Psychologists studies with animals

• Psychologists use animals because their physiological and psychological processes enable them to better understand the similar processes that operate in humans.

• Ethical guidelines in animalsEthical guidelines in animals in experiments: Rarely do they experience pain in psychological experiments.

• Ethical treatment of humans urge investigators to obtain informed consent, protect subjects from harm and discomfort, treat information about individuals confidentially and fully explain the research afterward.

Psychologists values and knowledge

• Personal values can influence psychologists research and its application

• Knowledge can be used for good and evil. Applications of psychology

• ‘s on