Audio: In this lecture we are going to address psychology as a science. Slide #2

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1 Psychology 312: Lecture 2 Psychology as a Science Slide #1 Psychology As A Science In this lecture we are going to address psychology as a science. Slide #2 Outline Psychology is an empirical science. Characteristics of a good theory. Goals of psychology as a science. Types of scientific design. In doing so we will begin by outlining why psychology is identified as an empirical science. We will address the characteristics of a good theory. We will talk about the goals of psychology as a science. Finally we will provide an overview of some of the types of scientific design. Slide #3 No Title Ways of understanding or knowing in psychology scientific method reason & logic + systematic observation this combination means that psychology has roots in philosophy psychology is fundamentally empirical. In the previous lecture we highlighted the various ways that one could understand or know the world. We know want to talk more specifically about how understanding and knowing our defined in psychology. We are going to do that by expanding our discussion of the scientific method. As you will recall from the previous lecture we outlined how the scientific method is the combination of reasoning and logic plus systematic observation. I m returning to this issue once again, because I simply want to highlight that this combination means one that psychology has its roots in philosophy and two psychologies is fundamentally an empirical discipline. This means that we use observation and experimentation to test the validity of our claim. Slide #4 Primary Goals of Psychology as a Science Description Prediction Understanding causality Application Psychology achieves these goals by using the scientific method to develop, test and revise theories about behavior. As a science psychology has some primary goals. Those goals include: description, prediction,

2 understanding causality and application. Let s take for a moment the topic of intelligence a topic that many psychologists are interested in studying. At the descriptive level we would be interested in asking questions like what types of behaviors or skills define intelligence. Or said another way what types of behavior or skills would we be looking for to determine whether someone was highly intelligence whether if they were just of average intelligence. At the predictive level we would be asking whether knowing something about one variable would help us predict something about another variable. So in the case of intelligence does knowing an individual s level of intelligence help us predict something else about that individual? Like perhaps that individual s grade point average or perhaps his or her score on the graduated mission exam or perhaps that individual s future career. Those would be questions related to prediction. Causality is a slightly more sophisticated question and often times one that is more difficult to answer. In this case we are not looking to see if merely knowing something about one variable helps us predict something about another variable. We are asking more specifically if manipulations in one variable produce changes in the other variable. So in the area of intelligence are their certain manipulations that can be done that can in fact influence an individual s intelligence. So for instance does exposing a child to some early specialized training in fact alter the level of intelligence that child will be able to achieve over the course of his or her lifetime. Then finally we have application. Obviously it is the hope in the arena of psychology that what we learn based on based on the scientific method about description and prediction and causality will ultimately be able to use to develop applications that are relevant in the real world. So for instance if there is something to be said for early exposure to particular types of stimulation or training that type of exposure influences early intelligence then maybe there is the grounds for producing something like the baby Einstein videos and the exposure to those types of videos to a small child actually can improve his or her intelligence as an adult. Those are the types of questions. Now collectively all of these goals are achieved in psychology by using the scientific method to develop tests and revise theories of behavior and that is really what we are going to focus on today. Slide #5 Generic Steps in the Scientific Method Make some casual observations form a question (hypothesis) choose a method verify with testing & systematic observations draw conclusions (What do results suggest about variables?) --? Develop, revise or extend support for a theory. New data leads to additional questions (hypotheses) & theory development. At this point I think it will be helpful to quickly revive the generic steps in the scientific method. As many of you know the scientific method typically begins with a set of casual observations. Out of those casual observations one begins to formulate a central question or what we call a hypothesis. The hypothesis will formally state the potential relationship between a set of variables. Once the hypothesis is stated then we must choose a particular method by which to test that hypothesis. Different methods will be appropriate for different types of hypotheses and we will talk about a variety of methods in the course of this semester. Once the method is chosen you then have to actually carry out your study. That will involve testing and systematic observation which will ultimately produce data, which we can draw conclusions. We can start to ask now whether the results that we have obtained can in fact filter back and support our original

3 hypothesis or fail to support it. Ultimately our goal here is to develop, revise or extend support of a particular theory and then that theory will guide future questions about the same variables. Slide #6 Psychology as a Theoretically Driven Discipline What is a theory? o A system of interrelated ideas used to explain and understand what we observe. Well if the ultimate goal of the scientific method is theory development what do we mean by a theory? Well formally a theory is a set of interrelated ideas used to explain and understand what we observe. Slide #7 Psychology as a Theoretically Driven Discipline Characteristics of a good theory o Falsifiable (i.e., testable): The theory is stated in such a way that, if tested, at least one possible outcome would show the theory is incorrect. o Fruitful: makes accurate/ correct predictions. o Has adequate scope: does not predict all possible outcomes. o Parsimonious: makes as few assumptions as necessary to explain the observed data. o Conservative: consistent with already established scientific thinking (?) All good theories are defined by a set of central characteristics. By definition a good theory is a theory that is falsifiable, fruitful, has adequate scope, is parsimonious and is conservative. Let s talk about each of these characteristics in turn. The term falsifiable is somewhat unfortunate, because it makes it sound as if I m saying our theory should be false, but actually falsifiable simply means testable. Or said another way the theory must be stated in such a way that if tested, at least one possible outcome would show the theory is incorrect. Now we do not actually want to observe that outcome, because we do not want our theory to be false. But we want the theory to be stated in such a way that outcome is possible therefore making our theory falsifiable. Fruitful any good theory should make accurate or correct predictions. Obviously a theory that makes incorrect predictions is a theory that must be revised. Has adequate scope this characteristic simply means that a theory should not predict all possible outcomes and this characteristic relates back to the idea of falsifiable. If a theory predicts all possible outcomes then their cannot be an outcome among them that if observed would show the theory as incorrect. So a theory that predicts all possible outcomes is by definition a theory that is not falsifiable. Parsimonious in science we tend to favor explanations that favor the fewest assumptions. So if I m considering two competing theories and those two theories are both equally capable of explain the observed data. Science says I should favor the theory that makes the fewest number of assumptions. Finally conservative means that we tend to favor theoretical explanations that build upon already established scientific thinking. Now you will notice that for this characteristic I have included a little question mark. I should make a side comment here there is some thinking within the scientific community that some of the most important theoretical explanations are

4 those that have completely rejected the main stream thinking of their time and so this last characteristic is somewhat debatable, but I have included it because I think more often than not we like theories that are conservative. Slide #8 Generic Steps in the Scientific Method Make some casual observations form a question (hypothesis) choose a method verify with testing & systematic observations draw conclusions (What do results suggest about variables?) --? Develop, revise or extend support for a theory. Types of method depends upon the question asked: naturalistic observations correlational studies experiments. Now let s return to the visual outlining the specific steps in the scientific method. I previously mentioned that in the third step where you must choose a method there are a number of potential methods that could be utilized. The type of method selected will relate formally to the hypothesis being tested. We will talk about a number of different types of methods over the course of the semester. Today I simply want to introduce a couple of methods, some general categories, which are very common in some of the social sciences. They include: the naturalistic observation, the correlational study and the experiment. Slide #9 Naturalistic Observation Nonintrusive description of real-world phenomena. o Observe behavioral patterns. Designed to describe rather than explain behavior. o No or minimal researcher interference o No variable manipulation By definition the naturalistic observation is the non-intrusive description or real world phenomena. The social scientists usually use the naturalistic observation to observe behavioral patterns as they occur in the real world. In doing so the primary goal is to describe a behavior rather than explain it. The naturalistic observation typically involves no or minimal researcher interference. It typically involves a lack of variable manipulation. That means that there is not attempt to manipulate some aspect of the environment to try to change the behavioral pattern that is being observed Jane s Goodall s work with chimps is a classic example of the naturalistic observation. Slide #10 Correlational Method Used to determine if there is an association between two variables (i.e., whether the variables co-vary). o Ask if knowing something about one variable (x) allows you to predict something about another variable (y). In contrast to the naturalistic observation that is primarily focused on description the correlation

5 method is used when we want to determine if there is a possible association between two variables of interest or said another way if we want to determine whether those variables co-vary. We are simply asking if knowing something about one variable, say variable X, allows us to predict something about another variable, variable Y. Slide #11 Types of Correlations Positive correlation o Variables move in the same direction. Increase together Decrease together. Negative correlation o Variable moves in opposite directions As one increases, the other decreases. Broadly speaking there are two types of correlations. There are what we call positive correlations and there are negative correlations. In a positive correlation the variables of interest move in the same direction. What we mean by this is that as one variable increases so does the other variable. Or in contrast as one variable decreases so does the other variable. In a negative correlation the variables move in opposite directions that is to say it increases in one variable are associated with decreases in the other variable. Let s return to the idea of intelligence a topic which we mentioned previously. It may be the case that knowing something about an individual s intelligence level allows us to predict something else about that individual. So for instance if higher levels of intelligence or if increases intelligence are associated with increases in SAT scores then we have a positive correlation between those two variables. In contrast if higher intelligent scores are associated with fewer F s on a student s transcript then we would have a negative correlation. Slide #12 Correlational Method NOTE: Correlations do not determine causality. It is important to note before we move forward that correlations alone do not determine causality. That is to say nearly showing that there is a relationship between two variables is not the same thing as showing that one variable produces changes in another variable. Knowing something about an individual s level of intelligence for example might help us predict his or her SAT score, but we cannot be sure based on that information alone that it is intelligence that is driving differences in those SAT scores. Slide #13 Side Note: Criteria for Causality Covariation of events/ variables o When one changes, so does the other. Time-order relationship.

6 o One variable must reliably precede the other. Elimination of plausible alternative causes/variables. o The possible influence of other variables must be ruled out. In fact to demonstrate causality between variables you must satisfy three separate criteria. You must demonstrate co-variation of events or variables. You must show for instance that changes in one variable are reliably associated with changes in the other variable. You must also demonstrate a reliable time order relationship. That is to say one variable must reliably precede the other variable. Finally you must be able to eliminate the possible influence of other alternative causes or other variables. In doing so you have ruled out the possibility that other variables could be affecting your variables of interest. The correlational study satisfies only the first of these criteria. The co-variation of events or variables. It cannot satisfy the time order relationship or the elimination of other possible variables. For that reason the correlation relational study falls short of being able to determine causality. Slide #14 Experimental Method Direct & systematic manipulation of variables to determine cause-effect relationships. o Used to determine whether changes in one variable will produce changes in another variable. o Researcher takes deliberate steps to arrange the experimental situation to reduce the possible effect of variables other than those being examined. To determine causality we must move to the experimental method. The experimental method involves the direct and manipulation of variables with the direct intension to determine cause and effect relationships. It is used to specifically to determine whether changes in one variable in fact produce changes in another variable. So it takes things a step further than what the correlational method can provide. The other aspect of the experiment that is important in addition to the idea of variable manipulation is that the researcher takes deliberate steps to arrange the experimental situation in such a way that it reduces the possible influence of variables other than those being examined. Slide #15 Primary Goals of Psychology As A Science Description Naturalistic Observation Prediction Understanding Causality Correlation Application Experiment Now that we have reviewed the naturalistic observation, the correlational study and the experiment we can relate those methods back to the primary goals of psychology as a science. If you will recall that those goals included: description, prediction, understanding causality and application. The naturalistic observation fits very nicely at the descriptive level. The social scientists use the naturalistic observation to describe behavior as it occurs in the real world.

7 However this particular approach won t allow us to do much more than that. If we want to address questions related to prediction we will have to move to the correlational study. The correlation allows us to determine whether changes in one variable are reliably associated with changes in another variable. However for reasons that we have already discussed the correlation falls short of being able to address issues of causality and for that we need the experiment. Ultimately we hope that all three of tense methods will contribute to the final goal of application. Slide #16 Next Lecture That concludes this lecture. Next we will discuss Logic & Hypothesis Testing. That concludes this lecture. Next we will discuss Logic & Hypothesis Testing.