Chapter 2 Introduction & The Scientific Method

2.1 Science & Research

Science is the systematic generation of knowledge through observation. Research is the systematic collection and evaluation of evidence; it is the process by which science generates knowledge. These statements say a lot in just a few words; we will spend this section unpacking these statements.

2.2 The Scientific Method

The scientific method describes an iterative process of using observation to make an educated prediction, testing that prediction, seeing if the test partially or fully supports the prediction, and generating a conclusion. This, in itself, is an observation, so it supports the next iteration of the cycle. Psychological science involves:

1. Observe: Using informal observations , or the results from prior research, scientists wonder about the causes of thought or behavior. Scientists form a research question, which is a broad problem that can be addressed by research.
2. Predict: Scientists form a hypothesis, a sentence that explains their observations. 
3. Test: Scientists collect evidence to confirm or disconfirm their hypothesis.
4. Interpret: The results of the test are integrated with the hypothesis and prior knowledge to understand whether the hypothesis is partially, fully, or not-at-all supported. When done well, this is when new knowledge is generated.
5. Communicate: The new knowledge is disseminated, usually to other researchers working in the same area. We call the collection of written reports of research the scientific literature.
6. No study will provide a complete answer to the research question. With the knowledge communicated by the study, the cycle starts again.

2.3 Ways of Knowing

Science is not the only way to answer questions about thought and behavior. The scientific method has a long history but a short one in Psychology, with experimental psychology only emerging in Germany in the mid-to-late 1800s (Pelham & Blanton, 2019).

Intuition: If you answer based on what feels right, then you are using intuition. Intuition is arriving at a conclusion without much conscious thought.

Logic (rationalism): Logic is the use of reason. When we use logic, we apply what we already know as assumptions and then use them to draw conclusions, called inferences. An inference is logical if it follows from its premises. In other words, if the premises are true, is the conclusion also true?

Authority: When someone else, especially someone in a position of power, answers the question for you, you are appealing to authority.

Observation: Observation is the use of a direct source. You could observe something by using your own senses. You can also observe by using a device or another person to observe on your behalf. Reliance on observation is a central principle of the sciences.

2.4 Basic Principles of Science

The acceptance of certain principles defines a scientist. The most important of these are empiricism, determinism, testability, and parsimony.

2.4.1 Empiricism

Empiricism is the belief that knowledge is gained through observation. Evidence is empirical when it comes from observation. This is distinguished from knowledge from tradition (authority) or someone’s ideas (intuition). Through empiricism, our ideas about the world can be challenged, modified, and updated in light of new evidence. Freud’s model of the Psyche had three components: id, ego, and superego. He developed this model by understanding theories suggested by others and developing his own. Without observable evidence, collected in a systematic fashion, such theories are ideas, not facts.

2.4.2 Determinism

Determinism is the belief that all events have causes, and that those causes are systematic. Under this view, nothing is truly random. We may perceive what we see as randomness because we cannot observe or fully understand the complex network of casual factors that lead to an event.

2.4.3 Testability

A theory is testable when it can be confirmed or disconfirmed. Freud’s methods did not bother with testing: collecting observable evidence to confirm or disconfirm the components of the Psyche. Falsifiability takes this a step further. A theory is falsifiable when it can be proven wrong.

2.4.4 Parsimony

Parsimony is a principle that the simplest solution is preferred. You can think of parsimony as a decision rule for a rather specific situation: When two explanations for a phenomenon are equally supported with empirical evidence, the simpler explanation is to be preferred. Among the other benefits, this principle offers protection from conspiracy theories. Conspiracy theories can be attractive because they provide better explanations because they add complexity. But, for any observable phenomenon, there are an infinite number of complex explanations. For example, why do planes have white lines (contrails) following them? Water vapor is a simple explanation (supported by evidence that they have existed since World War II), but conspiracy theorists have suggested that they are due to a government plot to poison us with metals and toxins (see https://www.bbc.com/news/blogs-trending-42195511 for the story). The existence of a secret spraying program requires massive government coordination, not just in execution, but also in covering it up. Is there evidence this is happening? No; according to a 2016 study, all but one of 77 atmospheric scientists surveyed said there was no evidence of toxin buildup. How might a conspiracy theorist respond?

We could take a neutral approach and weigh the evidence for each explanation. Parsimony doesn’t apply if there is stronger evidence for one explanation than another. But if there is no or equal evidence for both explanations, then parsimony says to go with the simpler explanation. Parsimony means that we are conservative in applying explanations to observed phenomenon. We need enough empirical evidence to outweigh a simpler explanation.

If you’ve ever repaired something, like a car or a computer, you may have applied this principle. As you start to diagnose a problem, before you do anything else, do you initially assume that several parts have failed simultaneously or that a single part is the culprit?

2.5 Laws, Theories, and Hypotheses

Laws are broad statements about a phenomenon. Gravity is a law because it is something that has been demonstrated to exist and applies comprehensively across situations. Laws are rare in psychology because little to nothing about humans can be stated absolutely. More commonly, we need to qualify our statements. Working fewer hours may lead to higher grades, but that relationship will not be true for someone dealing with homelessness. We use the term theory to describe our current explanation for a phenomenon. A theory is a general statement about the relationship between two constructs. A theory might state that homelessness is a major stressor that causes low academic performance.

When a theory is structured in such a way that it can be tested, we call it a hypothesis. Hypotheses are best stated as a relationship between two constructs. For example, homelessness is related to academic performance such that people who are homeless will have lower academic performance than people who are not. This is a hypothesis because we could gather evidence against or in favor of the hypothesis.

2.6 Three Goals of Psychological Science

You may have noticed the term “construct.” There is an important distinction between constructs and measures. A construct is a “concept, model, or schematic idea” (Shadish, Cook, & Campbell, 2002, p. 506). Constructs are the big ideas that researchers are interested in measuring: depression, patient outcomes, prevalence of cumulative trauma disorders, or even sales. The problem is that we cannot access constructs directly, we have to make conclusions about them using measures. There is often disagreement and debate about how to define a construct. This is a big issue, and we will revisit the messy business of defining and using constructs later in the course.

Constructs are what we study. The goal of research psychology, then, is to identify and define constructs and then describe relationships between constructs. There are three goals here:

Describe the relationship between constructs. For example, what happens when you flip a light switch?

Explain why that relationship exists. Why does the light turn on when you flip the switch? Describe the circumstances when the relationship holds. Does the switch always cause the light to turn on?

2.7 Basic versus Applied Research

Basic research focuses on the generation of new knowledge. But we can also use knowledge to solve problems. If basic research tells us that people who are hungry have poorer recall (perhaps demonstrated in a task in a laboratory), then we might want to apply that knowledge in the form of an intervention, an action intended to change thought or behavior. We might give free breakfast in a school in the hopes that academic performance will improve. Recall that we do not really have laws in psychology because our findings almost never apply across all situations and environments. Because of that, there is usually a gap between the basic research and the intervention; we don’t know if the intervention will work on our specific problem. This is the major limitation of basic research; results often depend on the situation matching the phenomenon under investigation. A memory task is not necessarily the same as trying to do a high school class. Applied research focuses on the solution to a specific problem. An applied researcher might distribute free breakfast at one school and see if it outperforms a school without free breakfast. If you are thinking that the schools may differ in other ways than breakfast, you are using good critical thinking. This is the typical limitation of applied research; even if the breakfast school has higher performance, the findings might not apply outside of a school setting or even at a different level of school (i.e., elementary school). Basic research is better at uncovering truths that apply more broadly, but these increments are usually small.

But wait, there’s more! Some researchers identify squarely as basic researchers or applied researchers, depending on how important it is to them to solve specific problems with their research. But another way of thinking about basic and applied research was put forward by Stokes (1997) in his book Pasteur’s Quadrant. Research can try to develop our fundamental understanding, help us solve problems (which he called consideration of use), or do both.

.	No consideration of use	Consideration of use
Quest for Fundamental Understanding	Pure Basic Research (Niels Bohr)	Use-Inspired Basic Research (Louis Pasteur)
No Quest for Fundamental Understanding		Applied Research (Thomas Edison)

Table adapted from Stokes (1997). Images are in the public domain.

2.8 The Inductive Method and the Deductive Method

The method of induction means taking observations of specific cases and then generalizing outward, drawing conclusions about the phenomenon of interest. Imagine you interview an employee at a company and ask them what would make them more productive. Imagine that the employee said the office design really lowered their morale and productivity. If you then concluded that a new office design would improve productivity, you would be using the inductive method. The method of deduction means starting with a conclusion and examining specific cases to see if the rule applies. If you want to see if a new office design improves productivity, then you test that, you are using the method of deduction to see if you rule (hypothesis) applies. We use both methods in research.