Discover What’s Unique About Your Brain
There are surprising individual differences in consciousness. Here's why.
Updated December 13, 2024 | Reviewed by Davia Sills
You are more unique than you realize
Over your lifetime, you’ve learned that you differ from others in skills, natural aptitudes, values, beliefs, and a host of other factors ranging from food preference to political attitudes. But you might be shocked to learn just how different you are from others when it comes to your subjective conscious experience.
I got such a shock when I recently asked my wife, Chris, another writer, whether she heard the words she was writing in her head the way I do. (I don’t write as much as I take dictation from a voice in my head.)
She answered, “I don’t hear words at all while I’m writing or thinking; I just see images and write what I see .”
I’d gone my whole life assuming everyone heard a voice in their head when they wrote, read, or thought, but I discovered that’s not the case. At a recent conference of psychologists, I discovered that most people I queried there both “see” images and “hear voices” while reading, writing, or thinking, but some individuals only “see” images or only “hear” voices.
One individual said he neither “sees” mental images nor “hears” voices but experiences thoughts as “amorphous abstractions.”
Individual differences in conscious experience and the brain
Mental imagery arises when we imagine—versus experience with our senses—an object, person, event, or experience.
It turns out that individuals differ significantly along many dimensions of mental imagery, including the vividness of visual, auditory, tactile, motor, olfactory , and gustatory phenomena [2,4,5,6]. For instance, in 1 percent of the population, the vividness of imagined visual images seems as realistic as what those same individuals see through their eyes [11]. Such rare people have hyperphantasia .
Conversely, about 2 percent of the population cannot mentally “see” anything, having a condition called aphantasia [11]. The rest of the population falls on a continuum between extremes. These data have been gathered by administering tests such as the Vividness of Visual Imagery Questionnaire (VVIQ)[19].
Questionnaires such as the VVIQ might have limited validity because two people could differ from one another in the way they describe their conscious experiences, even though they experience identical mental imagery vividness.
To control for this limitation, neuroscientists have correlated scores on mental imagery questionnaires with functional brain mapping (fMRI) and neuroanatomical data in test subjects and found that individuals reporting the most vivid imagery had correspondingly higher activation of appropriate sensory brain regions (e.g., visual cortex for imagery, auditory cortex for acoustic imagery) [13,24]. The gray matter volume of visual cortical areas also correlates with reported imagery vividness, strengthening the likelihood that individual differences on tests such as the VVIQ aren’t due solely to differences in the way people report identical experiences [5].
Recently, fMRIs have been administered to test subjects who were given the same painful stimulus and asked to rate the severity of their pain on a 1 to 10 scale. There was a positive correlation between pain ratings for the stimulus and levels of activation of pain centers in the brain. Thus, some people really do have low or high thresholds for pain, probably because of the relative intensities of conscious pain sensations [3].
If you’re having trouble accepting that it’s possible to get inside someone’s head to experience what they do, here’s a simple demonstration of how to imagine the unimaginable: Recall how vivid images and sounds are when you dream, compared to how you later recall those same dreams while awake.
If you’re like most people, dream imagery is far more intense and realistic than consciously imagined imagery. Thus, the intensity of visual experience in your dreams probably approaches the conscious experience of individuals who imagine images as realistic as those they see with their eyes [25].
Even more ways your brain is unique
Our subjective conscious experiences differ along dimensions other than our five senses. Here are some examples:
Learn more about how special your brain is and why it matters
The reference section has links to questionnaires and other tests you can run on yourself and others to discover how your brain and subjective conscious experiences differ from those close to you in surprising ways [19, 20,21,22,23]. There is also a free at-home test for aphantasia [8].
Learning the different ways in which your brain and consciousness are unique could have benefits beyond stimulating conversations at dinner parties or around the water cooler at work: It could help you better understand your cognitive strengths and weaknesses and those of people who matter to you. For example, if your boss or spouse is aphantastic , communicate with them through writing or speech rather than images. But if significant people in your life are closer to the hyperphantastic end of the spectrum, communicate with drawings and pictures.
Speaking of drawings and pictures, new research shows a positive correlation between the vividness of mental imagery and artistic ability [27]. Thus, identifying children early who have exceptionally vivid mental experiences for images, music, or motor activity could help steer them towards courses, and even careers, in art, music, or sports where they could excel.
You may never discover whether your spouse, child, or boss “sees” the same red that you do, but by asking a few questions, you can get a good idea of how vividly they experience whatever it is they experience.
1 https://www.mdpi.com/2076-3425/14/8/795 (Body self consciousness)
2 https://www.cell.com/current-biology/fulltext/S0960-9822(14)00137-7 (visual consciousness)
3 https://www.pnas.org/doi/full/10.1073/pnas.1430684100 (Pain)
4 https://link.springer.com/article/10.3758/s13421-021-01209-7 (mental imagery)
5 https://www.sciencedirect.com/science/article/pii/S0042698906005566 (Neural correlates of imagery vividness)
6 https://pmc.ncbi.nlm.nih.gov/articles/PMC2797860/#:~:text=Motor%20imagery%20is%20the%20mental,brain%20areas%20as%20actual%20movement . (motor imagery)
7 https://pmc.ncbi.nlm.nih.gov/articles/PMC6632740/ (synesthesia)
8 https://aphantasia.com/article/science/binocular-rivalry/ (test for aphantasia)
9 https://give.uwmedicine.org/stories/against-the-odds/ (unilateral color blindness)
10 https://davidfmarks.net/vividness-of-visual-imagery-questionnaire-2/ (Vividness of mental imagery test)
11 https://www.sciencedirect.com/science/article/pii/S0010945221003488 (VVIQ statistics)
12 https://pmc.ncbi.nlm.nih.gov/articles/PMC11518826/ (Statistical distribution on VVIQ test)
13 https://pmc.ncbi.nlm.nih.gov/articles/PMC4816805/ (Neural correlates of auditory mental imagery)
14 https://pmc.ncbi.nlm.nih.gov/articles/PMC3222625/#:~:text=Synesthesia%20is%20a%20condition%20present,in%20additional%20modalities%20%5B2%5D . (synesthesia statistics)
15 https://pmc.ncbi.nlm.nih.gov/articles/PMC7033456/#:~:text=Recent%20task%20fMRI%20studies%20suggest,are%20stable%20across%20task%20demands . (fMRI empathy)
16 https://www.sciencedirect.com/science/article/pii/S1053811912005691 (Brain volume and empathy)
This article is part of the Bringwise Psychology Journal — daily insights on human behavior, mental health, and personal growth.