Research using fMRI to investigate complex cognitive behaviour, or controversial political issues, is often criticized – sometimes unfairly, but also often for good reasons. (A colleague of mine is prone to quip: “You shouldn’t conduct fMRI experiments that involve regions anterior to the central sulcus!”) In general, many of the problems with such fMRI studies stem from a more fundamental problem: on the one hand we want to know more about the most complex behaviour and cognitive mechanisms exhibited by the human brain (how are political beliefs formed?, what is romantic love?, etc.); on the other hand, due to this complexity, it is seldom possible to design experiments that lend themselves to a straightforward, and clear cut, interpretation.
A new study, in press at Neuroscience Letters, illustrates this conundrum. Mario Beauregard and Vincent Paquette scanned 15 Carmelite nuns as they experienced what the abstract refer to as a “a state of union with God”. In other words, Beauregard and Paquette have tried to design an imaging study that can tell us something about what goes on in the brain of people having a mystical experience. There are several reasons why this is interesting. One, mystical experiences are clearly, by themselves, a fascinating type of phenomenal experience. Scondly, since mystical experiences are very rare, it is naturally of interest to know more about why people sometimes leave their normal state of mind and engage in such “spiritual” experiences. And thirdly, understanding the neurobiological underpinnings of mystical experiences can help us understand the more basic question why religions are such an attraction to humans.
The problem with Beauregard and Paquette’s study lies in the unprecise nature of the experimental design. Beauregard and Paquette acquired MR images of the nuns’ BOLD signal vis-a-vis three different conditions: (1) a mystical condition, (2) a control condition, and (3) a baseline condition. Here’s how these three conditions are described in the paper:
In the Mystical condition, subjects were asked to remember and relive (eyes closed) the most intense
mystical experience ever felt in their lives as a member of the Carmelite Order. This strategy was adopted given that the nuns told us before the onset of the study that “God can’t be summoned at will.” In the Control condition, subjects were instructed to remember and relive (eyes closed) the most intense state of union with another human ever felt in their lives while being affiliated with the Carmelite Order. The week preceding the experiment, subjects were requested to practice these two tasks. The Baseline condition was a normal restful state (eyes closed).
In other words, what was actually investigated was the memory of previous mystical experiences, more so than the actual “union with God” proclaimed in the abstract. Beauregard and Paquette’s idea i now to compare the mystical condition with the control and the baseline condition. It is however somewhat unclear how the memory of a mystical experience match the memory of an “intense state of union with another human” (who?), and thus how the two conditions can be compared.
Another concern is the very long duration of the individual blocks. Each block lasted 5 minutes, which makes perfect sense from the point of view of the task (after all, the subject needs time to bring about the two principal conditions), but makes it enormously difficult to know what is being modelled by the analysis. To my knowledge no theory exists detailing how the time-course of calling up a memory of a mystical experience unfolds; hence, exactly what cognitive processes are reflected by the BOLD signal remain uncertain. Moreover, it is hard to make sure that people concentrate on just one cognitive task for such a long time, so the results may be contamined by unrelated mental activity.
Still, with these serious caveats in mind, it is interesting to see that the contrast between remembering the experience of a union with God and remembering the experience of a union with another human produce significant acitivity in a number of brain areas (medial OFC, medial PFC, dorsal ACC, middle temporal cortex, and the inferior and superior parietal lobule), albeit at p<0.001, uncorrected for multiple comparisons. This result indicate that (the memory of) mystical experiences do have some particular neural correlate, although the design of the experiment makes it impossible to say what the function of the brain regions mentioned above amount to.
Now, it is obviously highly unclear what this experiment shows, but this doesn’t make it a failed study in my view. Whenever we deal with complex cognitive processes, we have to start somewhere. If other researchers use others conditions we may slowly be able to piece together the puzzle of what these activations mean.
Beauregard, M. & Paquette, V. (2006): Neural correlates of a mystical experience in Carmelite nuns. Neuroscience Letters, in press.