Imagination as the Constructor of Your Reality

What if the world you experience is not merely received but actively constructed? Contemporary neuroscience and philosophy suggest that your brain is not a passive receiver of external data, but an active constructor, meticulously building the reality you inhabit. Recent research demonstrates that the same brain neurons are activated when we imagine something and when we perceive something, providing a biological basis for visual imagination (Rutishauser et al., 2026). This means that the brain uses the same fundamental machinery for both perceiving the world and imagining it — merging the internal and external into a unified experience.

The Shared Neural Foundation

The brain’s ability to construct your reality is rooted in the principle of neural re-use. Studies show that activity in the visual cortex — the region at the back of the brain responsible for processing what we see — can be used to decode the content of both perception and mental imagery (Dijkstra et al., 2019). This means that when you imagine a red apple, the same neural networks in your visual cortex activate as when you actually see a red apple. Perception and imagery rely on similar patterns of connectivity in the brain, with the most notable difference being the absence of incoming sensory information during imagination (Dijkstra et al., 2019).

The visual cortex is located in the occipital lobe at the back of the head and is the brain’s primary processing center for visual information. It takes raw data from the eyes and transforms it into the images we consciously see. When we imagine, this same region is reactivated, effectively “painting” mental pictures using stored knowledge rather than external light signals.

This overlap is so profound that research from Cedars-Sinai found that when patients imagined images they had previously seen, about 40% of the visually responsive neurons reactivated using the same neural code as during the initial viewing (Rutishauser et al., 2026). In other words, the brain cells that fired when you first saw something fire again when you simply imagine it. The study’s lead author noted that “we generate a mental image of an object that we have seen before by reactivating the brain cells we used to see it in the first place” (Rutishauser et al., 2026). Further research has confirmed that perception and imagery share both fine-grained and coarse patterns of neural response in the early visual cortex (Huang et al., 2023).

How the Brain Distinguishes Reality from Imagination

Given this overlap, a crucial question arises: how does your brain know what is real and what is imagined? This ability, known as perceptual reality monitoring, is essential for maintaining a coherent sense of self and distinguishing between our inner world and the external world (Dijkstra & Fleming, 2023).

A 2025 study in Neuron identified a two-part neural basis for this process:

1. The Fusiform Gyrus: The Reality Judge

The fusiform gyrus is a region in the temporal lobe, located on the underside of the brain, roughly behind the ears. It is part of the visual cortex and is known for its role in facial recognition and object perception. Researchers discovered that the bilateral fusiform gyrus tracks the “sensory strength” of a signal (Dijkstra et al., 2025). When a perceived or imagined signal is strong enough — vivid enough in detail and sensory richness — it crosses a “reality threshold,” leading the brain to judge it as real (Dijkstra et al., 2025). This means that a very vivid imagination can sometimes cross this threshold, which is why daydreams or worries can feel so real. Activity fluctuations in the fusiform gyrus predict whether you will confuse an imagined scenario with reality on a moment-by-moment basis (Dijkstra et al., 2025).

2. The Prefrontal Cortex: The Final Decision-Maker

While the fusiform gyrus provides the evidence, a separate network in the prefrontal cortex integrates this information and makes the final binary judgment: real or imagined (Dijkstra et al., 2025). The prefrontal cortex is located at the very front of the brain, just behind the forehead. It is often called the brain’s “executive center” because it is responsible for complex cognitive functions: decision-making, planning, rational thought, and distinguishing between possibilities. When the perceptual system (the fusiform gyrus) is in doubt — when an image is just vivid enough to feel real but not clearly from the senses — the prefrontal cortex steps in. It may rely more heavily on higher-level predictions and expectations, a process that can be influenced by emotions, prior beliefs, and internal bodily signals.

Imagination as a Tool for Reality Construction

If the brain’s architecture blurs the line between perception and imagination, then imagination must be a primary tool for constructing reality. Predictive processing theories of perception argue that perception is effectively a controlled hallucination — an “imagination-first” process where the brain’s top-down predictions are the primary constructors of experience (Clark, 2013; Seth, 2016). In the words of neuroscientist Anil Seth, “the entirety of perceptual experience is a neuronal fantasy that remains tied to the world through a continuous making and remaking of better perceptual hypotheses” (Seth, 2021, p. 87).

What this means is that your brain does not passively wait for information from your eyes, ears, and skin. Instead, it actively predicts what you are likely to experience based on past knowledge and expectations, and then tests these predictions against incoming sensory data. Perception is the brain’s best guess about what is out there. Imagination may simply be the voluntary engagement of these same predictive pathways, freed from the need to match incoming signals. This view is supported by research showing that imagining a situation can generate the same predictive biases as actually observing it (Corlett, 2024).

The Existential and Ethical Dimension

The concept of imagination as the constructor of reality extends beyond cognitive science into philosophy, particularly existentialism. For the philosopher Jean-Paul Sartre, imagination was synonymous with freedom. In The Imaginary, he argued that “to posit the world as a world or ‘negate’ it is one and the same thing” (Sartre, 1966, p. 240). Sartre meant that the very act of imagining something that is not currently present is an act of transcending — going beyond — the given reality. This act of transcendence is what defines human consciousness and freedom.

For Sartre, there are two distinct states of consciousness:

• Perceptual consciousness grasps what is actually present in the world.

• Imaginative consciousness posits its object as unreal or absent.

These are mutually exclusive states; you can perceive a chair or imagine a chair, but you cannot do both at the same time (Sartre, 1940). Sartre’s view is summarized by the principle that “no matter how long I may look at an image, I shall never find anything in it but what I put there. It is in this fact that we find the distinction between an image and a perception” (Sartre, 1936). In other words, when you look at a real object, you receive information from the world. When you look at a mental image, you are only encountering your own mental activity.

In this understanding, the ability to imagine is a prerequisite for human freedom, since without imagination, “we would be absorbed by the intuitions of the real and we could not build a different world from the one we live in” (Cunha, 2011). Imagination allows us to envision alternatives, to plan, to hope, and to choose who we want to become.

This leads to an important ethical consideration. Architect Juhani Pallasmaa warns that in a world increasingly dominated by simulation and fabricated realities — screens, virtual worlds, and carefully manufactured images — the ethical task of the artist and architect is not to invent new fictions but to defend and strengthen our experience of the real (Pallasmaa, 2021). In other words, with great imaginative power comes responsibility: the worlds we build in our minds and in our cultures matter, and they shape how we experience life.

Conclusion

The scientific and philosophical evidence points to a profound conclusion: imagination is not a departure from reality-processing — it is the same system, freed from the constraint of actuality. The brain has one fundamental generative system. When it processes what is actual, we call it perception and memory. When it generates what is possible, hypothetical, or fictional, we call it imagination. These are not different faculties — they are different modes of the same cognitive construction system.

You are the constructor of your reality, and imagination is your primary design tool. It is active in every perception, every memory, and every vision of a possible future. Understanding this is the first step toward wielding that power consciously.

References

• Clark, A. (2013). Whatever next? Predictive brains, situated agents, and the future of cognitive science. Behavioral and Brain Sciences, 36, 181–253.

• Corlett, P. (2024). Imagination, Agency, and Predictive Processing. In The Oxford Handbook of Predictive Processing. Oxford University Press.

• Cunha, K. S. (2011). A teoria sartreana da consciência e o problema da imagem [Master’s thesis, Universidade Federal de Uberlândia].

• Dijkstra, N., Bosch, S. E., & van Gerven, M. A. J. (2019). Shared Neural Mechanisms of Visual Perception and Imagery. Trends in Cognitive Sciences, 23(5), 423–434.

• Dijkstra, N., & Fleming, S. M. (2023). Perceptual reality monitoring: Neural mechanisms and computational principles. Nature Communications, 14(1).

• Dijkstra, N., von Rein, T., et al. (2025). A neural basis for distinguishing imagination from reality. Neuron, 113(15), 2536–2542.

• Huang, Y., Pollick, F., Liu, M., & Zhang, D. (2023). Gabor and Non-Gabor Neural Representations Are Shared between Visual Perception and Mental Imagery. Journal of Cognitive Neuroscience, 35(6), 1045–1060.

• Pallasmaa, J. (2021). The Eyes of the Skin: Architecture and the Senses. Wiley.

• Rutishauser, U., Mamelak, A., Tsao, D. Y., et al. (2026). Shared neural code for visual perception and mental imagery. Science.

• Sartre, J.-P. (1936). L’Imagination. Translated by Kenneth Williford and David Rudrauf (2012). Routledge.

• Sartre, J.-P. (1940). The Psychology of the Imagination. Translated by Mary Warnock (2004). Routledge.

• Sartre, J.-P. (1966). Being and Nothingness. Washington Square Press.

• Seth, A. (2016). Your brain hallucinates your conscious reality. TED Talk.

• Seth, A. (2021). Being You: A New Science of Consciousness. Faber & Faber.