by Chuck Ruby, Ph.D.
A recent study in Neuropsychologica about veterans and brain trauma is a prime example of how medical model thinking and nomothetic research design and analysis wrongly imply: (1) that meaningful human experiences can be best understood by looking at the brain; and (2) that differences between research groups as identified by statistical tests, mean that the class of people in one group share a common characteristic different from the class of people in the other group(s). Unfortunately for the authors of the study, this is not true.
First, the follow quotes from the study reveal how meaningful human experiences are falsely reduced to brain structures:
“…religious beliefs are critically represented in the anterior frontal lobe.”
“…fundamentalist religious beliefs arise from the integrated processing and computations in a distributed brain network….”
“…a vmPFC lesion induces increased fundamentalism.”
“…religious beliefs are partially dependent on correct functioning of the PFC.”
None of these statements are accurate. We’ll never find religious beliefs inside the skull and brain activity does not give rise to religious belief, even though religious belief cannot happen without brain activity. Religious belief, in addition to a plethora of other kinds of meaningful human experiences, can only be understood by understanding the individual person, and even that changes over time. Further, given that they are individuals, people are inescapably nuanced, complex, and unique in terms of the factors that interact and lead up to any one particular characteristic, such as religiosity.
It is true that damage to an area of the brain necessary for a person to have a certain opinion, belief, conviction, or feeling can change the person’s experience of those things. However, especially in the case of highly meaningful things, like religiosity, such changes occur more often not because of damage to those areas but because of experiential changes in living. This study never takes this into account: that veterans who have suffered TBI had more severe and meaningful experiences (both during the trauma and post-trauma) than those who hadn’t suffered TBI. How did those experiences, and not brain damage, affect their turn toward religious fundamentalism?
Regarding the second issue, there was a statistically significant difference in fundamentalism scores between the group of veterans who suffered damage to the ventromedial prefrontal cortex and the group with damage to the prefrontal cortex but outside the ventromedial and dorsolateral regions. Yet, the Cohen’s D was only .71. This means the two group distributions of fundamentalism scores overlapped around 73%.
Given this amount of overlap of groups, it does not justify the researchers’ claim that, “…participants with vmPFC lesions reported greater fundamentalism.” or “[p]atients with vmPFC lesions scored higher in fundamentalism than patients without PFC lesions….” Neither of these claims represents the data. In fact, a large number of people in the ventromedial group had lower fundamentalism scores than the other group, and vice versa, contrary to the claim. If damage to that region increases religious fundamentalism, it should apply to all of them.
Moreover, the amount of variance in the data explained by the ventromedial lesions was only 1%. That means 99% of the observed variance in fundamentalism data among the participants was due to something other than the lesions. In fact, this study found that openness (9.7%) and cognitive flexibility (4.6%) explained far more variance in the data than did the lesions. This suggests a person’s subjective understandings of the world, separate from brain injury, are more important in understanding religiosity. And note that even with all of the studied variables included, only about 18% of the variance was explained; 82% was unexplained. This is the important statistic. Much of what people do can't be explained by using medical model, nomothetic approaches. It is important to understand one person at a time.
Despite the above, the “moral of the story” according to the authors is how damage to brain structures affects one’s religious fundamental beliefs. This perpetuates a medical model of humanity that reduces meaningful experiences to sterile brain activity, and it stereotypes people without even a minimal amount of justifying evidence.