The human imagination: the cognitive neuroscience of visual mental imagery
Pearson, J. (2019). The human imagination: the cognitive neuroscience of visual mental imagery. Nature Reviews Neuroscience, 20(10), 624–634. doi:10.1038/s41583-019-0202-9
Abstract
Mental imagery can be advantageous, unnecessary and even clinically disruptive. With methodological constraints now overcome, research has shown that visual imagery involves a network of brain areas from the frontal cortex to sensory areas, overlapping with the default mode network, and can function much like a weak version of afferent perception. Imagery vividness and strength range from completely absent (aphantasia) to photo-like (hyperphantasia). Both the anatomy and function of the primary visual cortex are related to visual imagery. The use of imagery as a tool has been linked to many compound cognitive processes and imagery plays both symptomatic and mechanistic roles in neurological and mental disorders and treatments. Mental imagery plays a role in a variety of cognitive processes such as memory recall. In this review, Joel Pearson discusses recent insights into the neural mechanisms that underlie visual imagery, how imagery can be objectively and reliably measured, and how it affects general cognition.
Authors
- Joel Pearson30
The Secret Life of Your Mind's Eye
Have you ever closed your eyes and vividly pictured a sunset, an apple, or a face of someone you love? That invisible experience—that's your mental imagery, and it's one of the most fascinating yet mysterious abilities of the human brain. Yet here's something remarkable: not everyone experiences it the same way. Some people's mental images are photorealistic and vivid, while others—including those with a condition called aphantasia—can't voluntarily conjure mental images at all, no matter how hard they try. For decades, scientists debated whether this ability was even real or just something people imagined they could do. Joel Pearson's comprehensive review in *Nature Reviews Neuroscience* finally settles that question and reveals what's actually happening inside our heads when we imagine.
The core mystery that motivated this research is deceptively simple: How does the brain create conscious sensory experiences when there's nothing actually hitting our eyes? This question matters more than you might think. Mental imagery isn't just about daydreaming or artistic inspiration—it's involved in nearly everything we do cognitively. When you plan your day, memorize facts, recall a conversation, make moral decisions, or even play sports mentally before performing them, you're using imagery. It's also deeply connected to mental health. People with PTSD, depression, and other conditions experience unwanted, involuntary imagery that can be clinically devastating. Conversely, therapists can harness controlled imagery as a powerful treatment tool. Yet despite its central importance to human cognition, we've understood remarkably little about how it actually works in the brain—until now.
For much of the twentieth century, psychologists and neuroscientists were stuck in what researchers called "the imagery debate." They couldn't agree on something fundamental: when you imagine something, is your brain storing and retrieving information like a computer stores text files (symbolic representation), or is it more like pulling up an actual picture (visual representation)? This wasn't a trivial philosophical question—it determined how scientists designed experiments and what brain areas they looked for. The debate raged from the 1970s through the 2000s, consuming enormous research effort without resolution.
Pearson's review reveals that modern neuroimaging technology has finally moved us past this impasse. Here's what recent research has discovered: Mental imagery activates a widespread network of brain regions, from your frontal cortex (involved in planning and conscious control) all the way back to your sensory cortex—the same areas that light up when you actually *see* something. But imagery isn't just perception in reverse; it's more like a "weak version" of real perception. When you imagine something, your brain is essentially creating a simulation, filling in visual details based on memories of what you've actually seen.
One of the most striking findings involves the primary visual cortex (V1), the brain's main visual processing hub located at the back of your head. Counterintuitively, people with stronger, more vivid mental imagery actually have *smaller* primary visual cortexes than people with weaker imagery. Researchers found this pattern not just in healthy volunteers but also across different clinical populations—people with PTSD, schizophrenia, and stimulant addiction. The smaller the visual cortex, the stronger the imagery. This suggests something profound: a more compact visual processing area might generate less "neural noise," allowing clearer mental images to emerge. Think of it like the difference between a photograph and one with static interference—less noise means a clearer picture.
The research also reveals something unexpected about how our minds differ. The spectrum of imagery ability is remarkably wide. On one end are people with aphantasia—individuals whose minds are completely "blind" when it comes to voluntary imagery. They cannot, no matter how hard they try, create a conscious visual experience of an imagined object. Researchers initially wondered if this was just a reporting problem, perhaps these people had imagery but didn't notice it or described it differently. But objective measurements proved otherwise. When tested with sophisticated methods like binocular rivalry (a technique that measures the sensory strength of visual experiences), people with aphantasia scored significantly lower, confirming their lack of imagery is real, not merely a difference in awareness or vocabulary.
On the opposite end of the spectrum lies hyperphantasia (previously called eidetic imagery)—the rare ability to create almost photorealistic mental images. These individuals, typically children, experience imagery so vivid and detailed that it feels projected into external space rather than happening inside their minds. Unlike afterimages that fade, eidetic images remain stable and retain their colors. It's a genuinely different phenomenon from normal imagery.
Perhaps most intriguingly, the research shows that people with aphantasia still performed *slightly better than average* on tests measuring spatial imagery—the "where" aspect of vision (location, direction, movement) rather than the "what" aspect (color, form, detail). This suggests aphantasia might involve a specific disruption along the brain's dual visual processing pathways: one stream processes *what* something is, while another processes *where* it is. The fact that these can partially dissociate tells us the brain's imagery system is more specialized and nuanced than previously thought.
Why should any of this matter to you? Because mental imagery strength directly affects performance on an astonishing range of cognitive tasks. If you have vivid, strong imagery, you'll likely perform better on visual working memory tests (remembering what you see), episodic memory (recalling personal experiences), reading comprehension, and even moral decision-making. Weaker imagery correlates with potentially less reliable eyewitness memory—a finding with obvious implications for criminal justice. Some research even suggests imagery connects to creativity and athletic performance.
The practical implications extend to treatment and intervention. Understanding that imagery varies so dramatically across the population means we need to measure it accurately and account for it when investigating other cognitive abilities. It also opens doors for new therapeutic approaches. Since we can't change everyone's brain anatomy, but we *can* learn to control and manipulate imagery, therapists might develop better interventions for conditions where imagery is problematic—like intrusive thoughts in PTSD—while leveraging imagery's benefits for learning, memory, and mental preparation.
Pearson's review signals that we've moved from an era of philosophical debate to one of empirical understanding. We can now objectively measure imagery, map the neural networks involved, and understand how individual differences affect cognition and mental health. As imagery research gains new objective measurement tools and fresh momentum, researchers are poised to "reignite" investigations into extreme imagery abilities and unlock mysteries about how our remarkable ability to imagine shapes everything from memory to creativity to mental wellbeing.
This summary was generated by AI and may contain errors. Always refer to the original paper for accuracy.