Seeing figures or shapes at night, particularly in dim light or during sleep transitions, can be a disorienting experience. Many people report these perceptions, which often feel incredibly real. Understanding the common reasons behind these nocturnal visual phenomena can provide comfort and clarity, as they are often a normal physiological response of the brain.
Explanations During Sleep Transitions
Visual perceptions at night frequently occur during the natural shifts between wakefulness and sleep, known as hypnagogic hallucinations (falling asleep) and hypnopompic hallucinations (waking up). These are vivid, dream-like experiences the brain generates while not fully awake or asleep. Up to 70% of people may experience hypnagogic hallucinations at least once, making them common and generally not a concern. These hallucinations are often visual, presenting as patterns, shapes, flashing lights, or detailed images of faces, animals, or scenes.
Hypnopompic hallucinations are similar, occurring as one emerges from sleep and sometimes feeling like an extension of a dream. Both types can involve other senses, such as hearing sounds or voices, or feeling sensations like falling or weightlessness. During these transitions, the brain’s activity shifts, and vivid imagery typical of dreams can spill into conscious perception.
Sleep paralysis can accompany these hallucinations, where a person becomes conscious but is temporarily unable to move or speak. This immobility, combined with vivid hallucinations, can be particularly frightening, as individuals might perceive an intrusive presence, feel pressure on their chest, or sense a dark figure in the room. Sleep paralysis and its associated hallucinations are considered parasomnias and are generally harmless physiological occurrences.
How the Brain Interprets Darkness
The brain’s visual system actively works to interpret the world, even when light is scarce. In low-light conditions, visual input is ambiguous, and the brain attempts to make sense of the limited information it receives. This process can lead to misinterpretations of shadows, objects, or patterns, causing the perception of figures that are not actually present. This phenomenon is distinct from sleep-related experiences.
The brain is constantly filling in gaps in visual information, a process known as “filling-in.” For instance, the brain compensates for the eye’s natural blind spots by generating information based on surrounding visual cues. When there is insufficient light, the brain might rely more heavily on its stored memories and expectations to construct a coherent visual scene. This can result in pareidolia, where random patterns or indistinct shapes are perceived as meaningful images, such as faces or human-like figures.
This tendency of the brain to complete incomplete visual data means that a coat on a chair, a pile of clothes, or a curtain in the dark can be misinterpreted as a person or a shadow. The visual cortex, the part of the brain responsible for seeing, actively creates these perceptions when direct sensory input is limited. These visual illusions in darkness highlight the brain’s constructive nature.
Underlying Medical Conditions
While many experiences of seeing figures at night are benign, some instances can be linked to underlying medical conditions. These causes are less common than sleep-related phenomena or misinterpretations of darkness. Certain neurological disorders can involve visual disturbances. For example, some individuals with significant vision loss, such as those with macular degeneration, may experience vivid visual perceptions that are not real. These perceptions, ranging from simple shapes to detailed people or animals, are the brain’s way of filling the void created by reduced visual input.
Mental health conditions can also contribute to visual perceptions, particularly in severe cases of stress or anxiety. Additionally, some medications list visual disturbances as a side effect. Drugs used to treat high blood pressure, Parkinson’s disease, and even some antibiotics, antidepressants, and sleep medications have been associated with visual perceptions. These medication-induced experiences can be more likely when a person is taking multiple drugs or is older. Substance use or withdrawal can also induce visual perceptions.
When to Seek Professional Guidance
Consulting a healthcare professional is advisable if experiences of seeing figures at night become frequent, persistent, or distressing. If these perceptions interfere with daily life, cause significant anxiety, or lead to fear, it is important to seek an evaluation. This includes situations where the experiences are accompanied by other symptoms.
Other concerning symptoms that warrant medical attention include changes in sleep patterns, mood shifts, or cognitive difficulties. Sudden or unexplained changes in vision, like flashes of light or dark spots, should also prompt a visit to an eye doctor. Open communication with a doctor about the nature and frequency of these visual experiences can help determine if there is an underlying medical cause requiring attention.