Psych in Real Life: Brain Imaging and Messy Science

This is a little difficult for a psychologist to ask, but here goes: when you think of a “science” which one of these is more likely to come to mind: physics or psychology?

We suspect you chose “physics” (though we don’t have the data, so maybe not!).

Despite the higher “status” of physics and chemistry in the world of science over psychology, good scientific reasoning is just as important in psychology. Valid logic, careful methodology, strong results, and empirically supported conclusions should be sought after regardless of the topic area.

We would like to you to exercise your scientific reasoning using the example below. Read the passage “Watching TV is Related to Math Ability” and answer a few questions afterwards.

It is pretty surprising to learn that watching television can improve your math ability, and the fact that we can identify the area in the brain that produces this relationship shows how far psychology has progressed as a science.

Or maybe not.

The article you just read and rated was not an account of real research. Ian McAtee and Leo Geraci are not real people and the study discussed was never conducted (as far as we know). The article was written by psychologists David McCabe and Alan Castel for a study they published in 2008.^[1] They asked people to do exactly what you just did: read this article and two others and rate them.

McCabe and Castel wondered if people’s biases about science influence the way they judge the information they read. In other words, if what you are reading looks more scientific, do you assume it is better science?

In recent years, neuroscience has impressed a lot of people as “real science,” when compared to the “soft science” of psychology. Did you notice the pictures of the brain next to the article that you just read? Do you think that picture had any influence on your evaluation of the scientific quality of the article? The brain pictures actually added no new information that was not already in the article itself other than showing you exactly where in the brain the relevant part of the parietal lobe is located. The red marks are in the same locations in both brain pictures, but we already knew that “Results revealed that similar areas in the parietal lobes were active during TV watching…and during arithmetic solving.”

McCabe & Castel Experiment

McCabe and Castel wrote three brief (fake) scientific articles that appeared to be typical reports like those you might find in a textbook or news source, all with brain activity as part of the story. In addition to the one you read (“Watching TV is related to math ability “) others had these titles: “Meditation enhances creative thought” and “Playing video games benefits attention.”

All of the articles had flawed scientific reasoning. In the “Watching TV is Related to Math Ability” article that you read, the only “result” that is reported is that a particular brain area (a part of the parietal lobe) is active when a person is watching TV and when he or she is working on math. The highlighted part of the next sentence is where the article goes too far: “This area of the brain has been implicated in other research as being important for abstract thought, suggesting that both tv watching and arithmetic processing may have beneficial effects on cognition.”

The fact that the same area of the brain is active for two different activities does not “suggest” that either one is beneficial or that there is any interesting similarity in mental or brain activity between the processes. The final part of the article goes on and on about how this supposedly surprising finding is intriguing and deserves extensive exploration.

The researchers asked 156 college students to read the three articles and rate them for how much they made sense scientifically, as well as rating the quality of the writing and the accuracy of the title.

Everybody read exactly the same articles, but the picture that accompanied the article differed according to create three experimental conditions. For the article in the brain image condition, subjects saw one of the following brain images to the side of the article:

Graphs are a common and effective way to display results in science and other areas, but most people are so used to seeing graphs that (according to McCabe and Castel) people should be less impressed by them than by brain images. The figures below show the graphs that accompanied the three articles for the bar graph condition. The results shown in the graphs were made up by the experimenters, but what they show is consistent with the information in the article.

Finally, in the control condition, the article was presented without any accompanying figure or picture. The control condition tells us how the subjects rate the articles without any extraneous, but potentially biasing, illustrations.

Procedure

Each participant read all three articles: one with a brain image, one with a bar graph, and one without any illustration (the control condition). Across all the participants, each article was presented approximately the same number of times in each condition, and the order in which the articles were presented was randomized.

Ratings

Immediately after reading each article, the participants rated their agreement with three statements: (a) The article was well written, (b) The title was a good description of the results, and (c) The scientific reasoning in the article made sense. Each rating was on a 4-point scale: (score=1) strongly disagree, (score=2) disagree, (score=3) agree, and (score=4) strongly agree. Remember that the written part of the articles was exactly the same in all three conditions, so the ratings should have been the same if people were not using the illustrations to influence their conclusions.

Before going on, let’s make sure you know the basic design of this experiment. In other words, can you identify the critical variables used in the study according to their function?

Results for (a) Accuracy of the Title and (b) Quality of the Writing

The first two questions for the participants were about (a) the accuracy of the title and (b) the quality of the writing. These questions were included to assure that the participants had read the articles closely. The experimenters expected that there would be no differences in the ratings for the three conditions for these questions. For the question about the title, their prediction was correct. Subjects gave about the same rating to the titles in all three conditions, agreeing that it was accurate.

For question (b) about the quality of the writing, the experimenters found that the two conditions with illustrations (the brain images and the bar graphs) were rated higher than the control condition. Apparently just the presence of an illustration made the writing seem better. This result was not predicted.

Results for (c) Scientific Reasoning Assessment

The main hypothesis behind this study was that subjects would rate the quality of the scientific reasoning in the article higher when it was accompanied by a brain image than when there was a bar graph or there was no illustration at all. If the ratings differed among conditions, then the illustrations—which added nothing substantial that was not in the writing—had to be the cause.

Conclusions

McCabe and Castel conducted two more experiments, changing the stories, the images, and the wording of the questions in each. Across the three experiments, they tested almost 400 college students and their results were consistent: participants rated the quality of scientific reasoning higher when the writing was accompanied by a brain image than in other conditions.

The implications of this study go beyond brain images. The deeper idea is that any information that symbolizes something we believe is important can influence our thinking, sometimes making us less thoughtful than we might otherwise be. This other information could be a brain image or some statistical jargon that sounds impressive or a mathematical formula that we don’t understand or a statement that the author teaches at Harvard University rather than Littletown State College.

In a study also published in 2008, Deena Weisberg and her colleagues at Yale University conducted a study similar to the one you just read.^[2] Weisberg had people read brief descriptions of psychological phenomena (involving memory, attention, reasoning, emotion, and other similar topics). They rated the scientific quality of the explanations. Instead of images, Weisberg had some explanations that included entirely superfluous and useless brain information (e.g., “people feel strong emotion because the amygdala processes emotion”) or no such brain information. Weisberg found that a good explanation was rated as even better when it included a brain reference (which was completely irrelevant). When the explanation was flawed, students were fairly good at catching the reasoning problems UNLESS the explanation contained the irrelevant brain reference. In that case, the students rated the flawed explanations as being good. Weinstein and her colleague call the problem “the seductive allure of neuroscience explanations.”

Does it Replicate? The Messy World of Real Science

A few years after the McCabe and Castel study was published, some psychologists^[3] at the University of Victoria in New Zealand, led by Robert Michael, were intrigued by the results and they were impressed by how frequently the paper had been cited by other researchers (about 40 citations per year between 2008 and 2012—a reasonably strong citation record). They wanted to explore the brain image effect, so they started by simply replicating the original study.^[4]

In their first attempt at replication, the researchers recruited and tested people using an online site called Mechanical Turk. With 197 participants, they found no hint of an effect of the brain image on people’s judgments about the validity of the conclusions of the article they read. In a second replication study, they tested students from their university and again found no statistically significant effect. In this second attempt, the results were in the predicted direction (the presence of a brain image was associated with higher ratings), but the differences were not strong enough to be persuasive. They tried slight variations on instructions and people recruited, but across 10 different replication studies, only one produced a statistically significant effect.

So, did Dr. Michael and his colleagues accuse McCabe and Castel of doing something wrong? Did they tear apart the experiments we described earlier and show that they were poorly planned, incorrectly analyzed, or interpreted in a deceptive way?

Not at all.

It is instructive to see how professional scientists approached the problem of failing to replicate a study. Here is a quick review of the approach taken by the researchers who did not replicate the McCabe and Castel study:

• First, they did not question the integrity of the original research. David McCabe^[5] and Alan Castel are respected researchers who carefully reported on a series of well-conducted experiments. They even noted that the original paper was carefully reported, even if journalists and other psychologists had occasionally exaggerated the findings: “Although McCabe and Castel (2008) did not overstate their findings, many others have. Sometimes these overstatements were linguistic exaggerations…Other overstatements made claims beyond what McCabe and Castel themselves reported.” [p. 720]
• Replication is an essential part of the scientific process. Michael and his colleagues did not back off of the importance of their difficulty reproducing the McCabe and Castel results. Clearly, McCabe and Castel’s conclusions—that “there is something special about the brain images with respect to influencing judgments of scientific credibility”—need to taken as possibly incorrect.
• Michael and his colleagues looked closely at the McCabe and Castel results and their own, and they looked for interesting reasons that the results of the two sets of studies might be different.
  • • Subtle effects: Perhaps the brain pictures really do influence their judgments, but only for some people or under very specific circumstances.
    • Alternative explanations: Perhaps people assume that irrelevant information is not typically presented in scientific reports. People may have believed that the brain images provided additional evidence for the claims.
    • Things have changed: The McCabe and Castel study was conducted in 2008 and the failed replication was in 2013. Neuroscience as very new to the general public in 2008, but a mere 5 years later, in 2013, it may have seemed less impressive.

Do images really directly affect people’s judgments of the quality of scientific thinking? Maybe yes. Maybe no. That’s still an open question.

One Final Note

When we wrote to Dr. Alan Castel for permission to use his stimuli in this article, he not only consented, but he also sent us his data and copies of all of his stimuli. He sent copies of research by a variety of people, some research that has supported his work with David McCabe and some that has not. He even included a copy of the 10-experiment paper that you just read about, the one that failed to replicate the McCabe and Castel study.

The goal is to find the truth, not to insist that everything you publish is the last word on the topic. In fact, if it is the last word, then you are probably studying something so boring that no one else really cares.

Scientists disagree with one another all the time. But the disagreements are (usually) not personal. The evidence is not always neat and tidy, and the best interpretation of complex results is seldom obvious. At its best, it is possible for scientists to disagree passionately about theory and evidence, and later to relax over a cool drink, laugh and talk about friends or sports or life.