How are perceptions formed? Is your brain really showing you the world as it actually exists? What happens in the gap between what your senses detect and what you consciously experience?
In Subliminal, Leonard Mlodinow reveals how perceptions are formed through unconscious processes that fill in gaps and filter information. Your brain doesn’t simply record reality—it actively constructs it by making inferences, combining sensory data, and drawing on past experiences.
Keep reading to discover why you’ve never noticed your own blind spots and how your expectations might be changing the taste of your chocolate.
How Perceptions Are Formed
Your senses are constantly collecting information that helps you understand what’s happening around you. But Mlodinow explains that your conscious experience isn’t a direct result of the raw sensory data you take in. Instead, it emerges from the unconscious mind, filling in gaps and making intelligent inferences about the world around you. Let’s look into the details of how perceptions are formed in this way.
Filling Information Gaps
Mlodinow notes that the sensory data you take in is incomplete, ambiguous, and distorted: Your eyes have blind spots, your vision blurs at the periphery, and your ears miss small gaps in sounds. But you don’t consciously perceive these flaws because your unconscious mind enhances and interprets the sensory information it receives and constructs a more seamless reality for you to consciously experience.
For example, Mlodinow explains that you have blind spots in your vision, caused by the point where the optic nerve attaches to each of your eyes. While these blind spots create a hole in your visual field, you probably haven’t even realized that your eyes have blind spots. That’s because your unconscious mind infers what’s likely to be in the blind spot based on the surroundings and fills in the image accordingly.
Your brain finishes filling in gaps by combining input from multiple senses and incorporating prior knowledge. For instance, when you’re speaking with a friend at a noisy restaurant, your brain might miss certain words. Your unconscious mind fills in these gaps based on your knowledge of language, context, and what you’d expect the person to say. If they say, “Please pass the s___,” your brain automatically fills in “salt” rather than “saxophone,” drawing on your previous experience at dinner tables and your unconscious mind’s assumptions about what’s most likely to be said in that setting.
| The Price of Efficiency in The Little Prince While the unconscious mind’s ability to fill in gaps makes our perception more efficient, it may also limit what we can see—literally or metaphorically. This tension is captured in Antoine de Saint-Exupéry’s novel The Little Prince, particularly in an incident where adults see only a hat when they’re shown a drawing of a boa constrictor that has swallowed an elephant. The adults aren’t wrong exactly, because the drawing does resemble a hat. But their minds have become so efficient at categorizing familiar patterns and filling in gaps in ambiguous information that they miss other possibilities. Saint-Exupéry illustrates this price of efficiency through the oversights of his cast of grown-up characters: the businessman who only sees stars as numbers to be counted, the king who views everyone as subjects to be ruled, the lamplighter mechanically following his routine. Each character demonstrates how our minds can become trapped in efficient but narrow patterns of perception. The book’s famous line, “What is essential is invisible to the eye,” takes on new meaning when considered alongside modern neuroscientific insights about unconscious processing. While our unconscious mind helps us navigate the world efficiently by filling in gaps with expected information, as Mlodinow explains, Saint-Exupéry ponders whether true seeing might require occasionally overriding these automatic processes. Just as the pilot in The Little Prince must learn to see beyond his adult patterns of perception in order to understand how the prince sees the world, understanding how our unconscious mind works can help us recognize when we need to consciously look beyond our automatic interpretations to see things anew. |
Filtering Information
Your unconscious mind also plays a crucial role in determining what sensory information your conscious mind needs to be aware of. Mlodinow explains that your unconscious mind acts as a filter: amplifying or suppressing sensory signals based on how relevant or important they seem. It allows only a small portion of the sensory information you perceive to reach your conscious awareness: Otherwise you’d be overwhelmed by everything your senses perceive. For example, if you’re participating in a sport, you might not be aware of all the noise made by the crowd because your unconscious mind tunes it out and focuses your attention on things that are directly helpful to you, like what your teammates are communicating.
| The Hidden Language of Awe While Mlodinow focuses on how our unconscious mind filters consciously perceptible information, scientists say it also processes sensory information that exists beyond our conscious awareness entirely. Consider the case of whale songs: Blue and fin whales produce sounds as powerful as a supertanker’s engines, but much of their vocalizations occur at infrasonic frequencies—below 20Hz—too low for humans to consciously hear. (Even the vocalizations of 52 Blue, a blue whale who calls at a higher pitch of 52Hz, are inaudible to human ears.) Yet our bodies still perceive these vibrations, and research suggests this unconscious processing can trigger profound psychological responses. Scientists have found that when humans encounter infrasonic frequencies—whether from whale calls, pipe organs in cathedrals, or natural phenomena like storms—we often experience feelings of awe, unease, or even a sense of supernatural presence. We react with these emotions even though we’re not consciously aware of the sound itself and couldn’t hear it even if we tried. The phenomenon demonstrates how our unconscious mind doesn’t just filter what reaches our awareness, as Mlodinow notes, but also processes information our conscious mind can’t access at all. |
The Downside of Unconscious Sensory Construction
Because your brain actively constructs your perceptions based on sensory inputs combined with other factors like expectations, context, and prior knowledge, your perception isn’t always objective and accurate.
For example, let’s say you’re taste-testing various kinds of chocolates. Your brain integrates sensory information about each candy (its taste, appearance, texture, and so on) with contextual cues (like the brand, price, and packaging of each chocolate). These cues activate associations and expectations that shape your experience: Higher prices, recognizable brands, and more luxe packaging can lead you to conclude that one chocolate tastes better than another—even if they’re identical.
(Shortform note: While Mlodinow explains how our unconscious mind constructs our perception of reality, Ed Yong’s An Immense World reminds us that there isn’t a single “objective” reality for us to perceive. Every species experiences the world differently based on its unique sensory capabilities, from bats navigating by echolocation to sharks detecting electrical fields. What we consider “reality” is just the slice of the world that human senses can detect and our unconscious minds can process.)
