Admitting Psychology into the Science Club

by Brian Kurilla, PhD

Although the field of psychology has made considerable progress over the last few decades in establishing itself as a rigorous, scientific discipline, there are some who continue to criticize the field for being “unscientific.” These critics point to what they consider ambiguous terminology, a lack of experimental control, and ambiguous subjective measures of constructs like “happiness” and “life satisfaction” as reasons why psychology should be considered a “soft” science at best. However, these criticisms ignore the diverse methodologies and research areas within the field. There are, in fact, very good reasons to consider a different perspective.

As practices in the field have evolved, there are many who now argue that psychology is a science. It is not a “soft” science, and it is not a “social” science (a strange characterization implying that every psychologist investigates matters related to society and social interaction). Psychology is a natural science. And it is one that relies on rigorous experimental methods and measurements to make strong inferences about the underlying mental processes and environmental factors that control human behavior.

One reason people might think psychology is “unscientific” is that psychologists study mental processes, which are unobservable and unquantifiable. Although this is true, it is not something that is unique to this field. And psychologists circumvent this problem much the same way other sciences do—by relying on unambiguous measures of things that are related to a particular phenomenon and which can be quantified. Therefore even though psychologists are interested in the mind, we often measure overt behavior in the form of accuracy on a particular task (e.g., the number of words recalled on a memory test) or reaction time (e.g., how long it takes someone to push a button indicating recognition of a face) because these behaviors are guided by a vast number of underlying mental events.

And even though psychologists study the mind indirectly by measuring aspects of behavior, we can draw very strong conclusions about mental processing by relying on two fundamental aspects of any natural science, specifically rigorous experimentation and the human capacity for deductive reasoning.

Imagine that you are handed a black box with what appears to be two rods protruding from either side (call them rod A and rod B), and you are asked to figure out whether A and B are separate rods or two ends of a single rod. The black box is sealed on all six sides, so it is impossible to solve this problem by opening up the box to peer inside. How can you solve this problem?

The answer is that you can be a good scientist and perform a series of experimental manipulations on one of the rods. For example, first you might try pushing on rod A to see if this action has any observable effect on rod B. Imagine that when you push rod A inward toward the center of the box, rod B pushes outward on the other side. Following this single manipulation you conclude that there is a relationship between the two rods. However, the precise nature of this relationship is still unclear. Are rods A and B two ends of the same rod, or are they perhaps separate rods that bump up against one another inside the box? Answering this question requires another experimental manipulation. So, this time you might try to pull rod A outward from the center of the box. And imagine that when you try this there is no observable effect on rod B. Now, we can confidently conclude that A and B are separate rods, but that they probably bump up against one another inside the box (hence the reason they seemed to be related following the first manipulation).

This example serves as a nice analog to the problem faced by psychological scientists. Psychologists want to understand the nature of the relationship between a stimulus input (A) and a behavioral output (B), but the nature of this relationship is determined by unobservable mental operations that occur inside the black box, which in our case is the human brain. And even though we cannot peer inside the brain we can infer what is happening inside the brain by employing carefully controlled experimental manipulations of stimuli in the surrounding environment and by observing how these manipulations affect unambiguous, quantifiable measures of behavior.

This scientific approach to the study of the mind is common in a sub-discipline of psychology known as cognitive psychology, which deals with understanding everyday mental processes, such as attention, perception, and memory.  Consider the research of cognitive psychologist Elizabeth Loftus, whose work is now famous for reshaping our understanding of human memory. In a classic experiment by Loftus and Palmer (1974), participants were shown a video of a car accident and then asked to estimate how fast they thought the cars were going when the accident occurred. Critically, Loftus and Palmer manipulated the strength of the verb contained in this question. For example, some participants were asked, “How fast were the cars going when they bumped together?” whereas other participants were asked, “How fast were the cars going when they smashed together?” One of the critical findings from this experiment was that people gave higher speed estimates when they saw the question with the verb “smashed” compared to the verb “bumped.” More importantly though, when participants were reminded a week later of the video they had watched, participants who saw the question with the verb “smashed” were more likely to “remember” having seen broken glass at the scene of the accident. This occurred even though there was no broken glass in the video!

The study by Loftus and Palmer illustrates how psychologists combine rigorous experimental methods with systematic manipulation of key variables (in this case verb strength) to study unobservable mental processes like memory. This combined with unambiguous, quantifiable measures of behavior—specifically, people’s speed estimates and their reports a week later as to whether they remembered seeing broken glass at the scene of the accident—would certainly seem to yield  all the essential ingredients of a true, natural science.

BRIAN KURILLA

September 2, 2012

 

SELECTED REFERENCES
1 A. Berezow, "Keep psychology out of the science club," Newton Blog (2012). 2 E.F. Loftus and J.C. Palmer. "Reconstruction of automobile destruction: An example of the interaction between language and memory," in Journal of Verbal Learning and Verbal Behavior, 13, 585-589 (1974). 3 T.D. Wilson, "Stop bullying the ‘soft’ sciences." Los Angeles Times (2012).