Science on Religion

Exploring the nexus of culture, mind & religion

How the brain reacts to religious symbols, part 1

Religious icons white backgroundReligious symbols vary in all shapes and sizes: a cross, Star of David, crescent moon, the Buddhist wheel. For whatever reason, these particular symbols stood the test of time and people continue to find meaning in them. Rather than being content with “whatever reason,” neuroscientists Kyle D. Johnson (Jarvis Christian College) and colleagues wanted to find the neurological reason. In one of their key findings, they discovered that people subconsciously suppress their primary visual cortex when viewing negative religious symbols.

Importantly, Johnson and colleagues wanted to know whether the brain, through previous experiences and/or beliefs, affects how one interprets a symbol, or instead whether there’s something inherent in a symbol (such as its shape) that affects the brain in a certain way. In essence, does a brain educated in religious environment make the symbol religious, or is there something about the symbol that makes it religious? Taking a side, the researchers hypothesized that “religious symbols may interact with the brain on a primary level, and that religiosity may interact with the processing of negative and positive visual symbols differentially in the brain.”

Before they could test their hypothesis, the researchers first had to uncover symbols suitable for a neurological test. To do so, they gathered college students to assess 120 symbols in terms of emotional valence. The researchers wanted symbols that fell into five categories: religiously positive, religiously negative, nonreligiously positive, nonreligiously negative, and neutral (neither positive nor negative). The participants saw each symbol protected onto a screen for 2.5 seconds, pressing a button after each symbol disappeared in order to ensure the participants stayed awake. After viewing all of the symbols, the students rated the symbols in terms of religiosity and emotions.

This “pretest” filtered out unhelpful symbols for the purposes of the “real” test. Positive religious symbols that survived the pretest included a cross and a dove, negative religious symbols included an upside-down pentagram and a picture of Satan, positive nonreligious symbols included a smiley face, the sun, and a dollar sign, negative nonreligious symbols included a swastika, and neutral symbols included a square, an oval, and an equals sign.

Armed with these tested symbols, the neurologists could proceed to test their hypothesis. Twenty volunteers with religious backgrounds including Christian, Hindu, Jewish, and atheist agreed to undergo a blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) scan while looking at various symbols. This group of volunteers was not the same group who pretested the symbols.

The fMRI revealed that when viewing negative religious symbols, people had deactivations in multiple brain region that did not occur when they viewed neutral or positive religious symbols. Specifically, deactivation occurred in the medial occipital areas (primarily in the striate cortex) and the inferior, parietal, temporal, and anterior cingulate cortex. Non-religious negative symbols correlated with no deactivation whatsoever – something about the religious nature of the negative symbol seems to matter. Furthermore, by contrasting religious and nonreligious positive symbols, the researchers could see a difference in the level of striate cortex (part of the medial occipital area) activation.

All of this suggests, as the researchers put it, “that early stages of visual processing for religious stimuli was different for religious positive and religious negative symbols,” “that processing of negative religious stimuli may be suppressed in the brain,” and “that processing of religious stimuli is different for positive and negative stimuli.” In other words, in the primary regions of the visual processing, the brain already suppresses or accepts religious symbols.

Yet, even this is only the tip of the iceberg. The researchers also included surveys to measure religiosity and belief about the supernatural. When they coupled the survey data with fMRI imaging, they found very interesting correlations. But more on that in Part 2.

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