Psychology as a Science

I. Ways of knowing

A. Tenacity

B. Authority

C. Experience

D. Reason & Logic

E. Science

II. Components of the Scientific Method

A. Objectivity

B. Quantification

C. Replication

D. Self-correction

E. Control

III. The Psychological Experiment

A. Independent Variable

B. Dependent Variable

C. Extraneous Variables

Psychology's Claim to be a Scientific Enterprise

Many people say that psychology is a science. You can make up your own mind about this, but I want you to know the issues and why people make such a claim. Before I talk about what a science is and is not, I want to talk a little bit about how we know things, or how we think things are true. It turns out that there are lots of ways to know something to be true. Each of these has something to recommend it. Each of these can also be flawed, so that we may be mistaken when we think something is true. I want to introduce each and show how each can lead us astray.

I. Ways of knowing

A. Tenacity -- repetitive claims - we believe something is true because we hear it over and over. For example, advertisers want us to believe something, so they show it again and again.

1. advertising--Volvo wagon beats BMW; Tylenol for pain relief

2. teachings -- value differences; customer is always right

we don't need to be told that we like people who are similar to us. We have to be told repeatedly to celebrate how different we are from one another. Clearly, the customer isn't always right, but it's the way management wants us to act. Clearly, this can mislead us -- one can repeat a lie over and over.

B. Authority -- font of truth -- oracle; dictionary or encyclopedia; expert opinion-- when we play scrabble, we use a dictionary to determine if a word is legal. If the word is in there, it's legal; if not, it's not. It doesn't really matter if the word exists, we' re gonna follow this dictionary for this game. If we want to know some facts about a foreign country, we can look it up in an encyclopedia.

1. cow's teeth--I don't know who made up this story, but it's not mine. It's funny to me but nobody else. Here goes: A long time ago there was a monastery. One day the monks were all sitting down to dinner. They were arguing about the number of teeth that a cow has. On one side of the table, the monks were saying, "a cow has 28 teeth. It says so in Aristotle." On the other side they were saying "Nonsense, a cow has 30 teeth. It says so in Plato. " A young monk who had never heard this argument before approached the table and said "Brothers, we have lots of cows behind the monastery. Why don't we go and count the number of teeth that they have? " At this point, all the other monks got up, thrashed the young monk soundly, and sent him to bed without any supper. You see, the monks were reasoning by authority, and didn't want any other sort of way of knowing to enter into the argument. Reasoning by authority is often appropriate. However, authority can be wrong. Different authorities can disagree.

C. Experience -- direct personal experience of the world. Experience is often the most powerful reason to believe something to be true. If you experience it, you know. However, sometimes you experience things, but you are still wrong.

1. Out-of-body experience & other stress reactions--once I was in a car crash on a freeway. I remember looking down at the roof of the car, even though I know I was sitting in the back seat of the car. People have the experience of their whole life flashing before their eyes. People hallucinate.

2. Color-blind, tone-deaf - some people don't perceive the world the same as you. One of my best friends in high school was color blind. He found this out though a test. But he remembers his mother telling him to put on the red sox as a little kid. He couldn't figure which sox were the red ones.

3. Drugs - If you take serious drugs, pain killers, for example, they change your experience of the world. You can be mistaken about what the truth is, even if it's based on your own experience.

  D. Reason & Logic -- reason applied to assumption to determine particular case. Reasoning often can lead you to the truth. However, it doesn't always do so.

(deductive logic)

1. Faulty assumptions -- those most favored in heaven must be most favored on earth (assumption in Colonial America during the time of Cotton Mather) people thought that the richest people must be those most likely to go to heaven. If the assumptions are wrong, the logic can be right, but the conclusion can still be wrong.

2. Faulty conclusions -- "the facts, while interesting, are not relevant." This is a quote from an American politician. One wonders which facts he would find relevant. Ant legs and loss of hearing. This isn't my story, either, but I don't know whose it is. A guy has an ant and a pencil. He puts the ant next to the pencil and says, "crawl over the pencil." The ant does. He takes on of the legs off the ant, puts him back and says "crawl over the pencil." The ant does. He keeps on doing this and the ant keeps on crawling over the pencil, although more slowly. Finally he removes all the legs and tells the ant to crawl over the pencil. The ant doesn't move. The guy says "well, I can see that my ant can't hear any more." Reasoning doesn't always lead to the truth.

E. Science -- a set of procedures or techniques aimed at knowing things about the world rather than a specific topic or discipline. Science is a way of knowing, a way of finding things out so that what we find out is likely to be true. Science is aimed at developing convincing arguments. I'm going to spend some time describing the scientific method in detail. But before I do --

Do you think physics is a science? How about French? How about anthropology?

 I think some aspects of psychology are scientific but others are not. Doing psychotherapy is usually not. Evaluating the effectiveness of psychotherapy usually is.

 To see why, let's look at the scientific method.

II. Components of the scientific method

A. Objectivity -- free from subjective bias; consistent across measures

1. Multiple choice vs. essay--multiple choice is more objective than essay. It requires much less judgment.

2. Subjective assessment of job qualifications vs. work sample (e.g., welding, typing, etc.) --work sample is more objective than someone's opinion of a person's work. Scientific work is objective.

B. Quantified -- assignment of numbers rather than words; allows precision

1. How much breakfast cereal is a lot? Prime rib? One bowl? 8 ounces? 16 ounces? 32 ounces?

2. What temperature is warm? Hot?

Is it likely to be different for different people? Are the numbers more precise? Do you argue about where to set the thermostat at home? Scientific work uses numbers to stand for quantities.

C. Replication -- repetition of findings; allows confirmation or disconfirmation

1. SAT & GPA --there have been literally hundreds of studies that examine the relationship between standardized test scores and subsequent academic success. The association between the two is consistently less than perfect and consistently better than chance.

2. Cold fusion--some years ago a physicist claimed to have figured out how to make atoms fuse in a bottle without extreme heat. The scientific community could not replicate his study; no Nobel prize, buddy.

3. Fiedler's contingency theory of leadership; a prominent theory in industrial psychology says that certain kinds of leaders will be most effective in certain kinds of situations. Studies designed to test this notion typically fail to support it.

  D. Self correction--the scientific community uses empirical data and reason to solve disputes and correct errors (e.g., drive theories of motivation, malleability of cognitive ability test scores for individuals; use of personality tests for predicting sales performance) We try things out to see if they work. We collect data and interpret the results. We SHARE the results of our work with others in journals and at conferences.

E. Control -- manipulation of things of interest and elimination of unwanted factors

1. Manipulation

a. amount of light on factory floor (on widgets per hour) Hawthorne studies changed the amount of light in the factory and watched people to see how hard they worked.

b. amount of drug administered to rat (on bar presses)

c. type of training in tennis instruction (e.g., visualization, cross-training) (on matches won)

d. type of psychotherapy (e.g., implosion, desensitization) Implosion is being stuck in a room full of snakes until you get tired of being scared; desensitization is systematic relaxation while slowly getting closer to snakes(on touching snakes)

2. Unwanted factors

a. presence of psychologist on factory floor (Hawthorne effect) In the Hawthorne studies, people worked hard when they turned the lights up and when they turned the lights down. The people working were so glad that management was interested in them that they tried to be as helpful as possible.

b. drug induced reduction of hunger in rat as opposed to loss of coordination or perception (that is, drug works through something other than the thing of interest)

c. tennis trainees choose the type of training instead of being assigned Why is this a problem? Because the results can be due to the type of person rather than the type of instruction.

d. professional psychologists give one type of psychotherapy; student volunteers give the other

III. The psychological experiment

A. Independent variable -- the thing of interest as causal or explanatory, that which is manipulated (we also have independent variables in research where there is no manipulation, that is, in nonexperimental research)

1. Reinforcement schedule (on rats per hour caught)

2. Type of leadership, autocratic versus democratic (on profits)

B. Dependent variable -- thing to be explained, that which shows the effects of the independent variable.

1. As above (widgets per hour, fear of snakes, rats per hour, profits).

2. Things we would like to change or improve generally (e.g., subjective well being, money, or closer to home, school grades, graduation rates, or complaints about the administration of the university).

C. Extraneous variables -- factors other than the independent variable that can influence the dependent variable.

1. Sex of participants (e.g., on feelings vs. outward display of hostility).

2. Unintended experimenter effects (e.g., message about EP).

3. In any single experiment, it is virtually impossible to control for all extraneous variables; early studies control for the most obvious extraneous variables; subsequent research can control for more subtle variables.