Hallucinations and Misperceptions in Paranormal Investigation

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When investigating the paranormal, what we see (or think we see) matters. Many unusual experiences arise not from spirits or unknown forces, but from how the human mind perceives or misperceives the world around it. Misperceptions and hallucinations are two of the most common explanations skeptics turn to, but for investigators, they are more than dismissals. Learning to detect and differentiate them is crucial: a misstep could mean mistaking a trick of the mind for genuine evidence, or worse, overlooking a real event worth studying.

This article introduces practical tools and tables to help investigators recognize when a case may involve misperception or hallucination. Considering these factors can help investigators avoid premature conclusions, protect witnesses from harm, and sharpen their ability to tell the normal from the paranormal.

Detecting Misperception vs. Hallucination

Aspect	Hallucination	Misperception
External stimulus present?	No	Yes
Causes / Examples	Sleep-related hallucinations, sleep paralysis, sensory deprivation, medical conditions (epilepsy, delirium), drugs, magnetic fields, low blood sugar, caffeine overdose	Poor lighting, quick glances, ambiguous shapes, distant objects, unfamiliar situations
Investigator focus	Witness’s condition at the time	External conditions + sensory stimuli
Things to do	Consider whether the experience occurred without any external stimulus (e.g., hearing a voice in silence, seeing a figure where nothing was present). Look into the mental/physical state of the witness (fatigue, stress, illness, medication, intoxication, sensory deprivation, near-sleep state). Check for patterns of recurrence — repeated voices, visions, or sensations under similar conditions may suggest hallucination rather than one-off misperception. Consider cross-checking with other witnesses: if only one person perceives something when others in the same conditions don’t, hallucination is more likely. Remember that hallucinations can feel vivid, detailed, and emotionally intense, often more so than misperceptions.	Check for the presence of external sensory stimuli (e.g., objects, shadows, reflections, sounds). Recreate the original conditions — same location, lighting, angle, and distance of viewing. Pay attention to low-light or ambiguous settings, since many misperceptions occur under poor visibility. Test whether you or others can experience the same misperception; if not, the object or condition that caused it may no longer be present.

Source: Association for the Scientific Study of Anomalous Phenomena (ASSAP) article on Misperception

Understanding whether a witness experienced a hallucination or a misperception is more than academic nitpicking—it shapes the entire investigation. A hallucination points inward, suggesting the experience arose from the mind or body without an external trigger, while a misperception points outward, rooted in real stimuli distorted by context. Mistaking one for the other can lead investigators down the wrong path, either dismissing a case too quickly or chasing a phantom caused by shadows and suggestion. Clear distinctions help keep the focus where it belongs: uncovering what is truly happening.

Common Visual Triggers for Misperception

Though misperception has been studied quite extensively in the laboratory, it is not so well documented in the field. Perhaps this is a gap that paranormal researchers could fill! The following examples of visual misperception 'triggers' are anecdotal, so it should not be taken as a definitive or exhaustive list.

- Maurice Townsend

Misperception Trigger	Explanation/Examples
quick glances	objects are often misinterpreted when only seen briefly (see also here).
poor viewing conditions	dim light, bright light, highly coloured light, fog, bright light source from a low angle (eg. the sun in winter at high latitudes) etc can all produce misperception
corner of the eye phenomena	poor resolution on the edge of the visual field produces misperception
distant objects	these can be the subject of visual substitution
ambiguous shapes	simulacra, optical illusions, etc.
partial views of an object (eg shape obscured)	if the shape is partly obscured an object may be misinterpreted
rapid head turning	may cause apparent movement in the new scene even when everything is stationary
slow moving objects	may be difficult to recognise while in motion
fast moving objects	may 'vanish' if they do not move as predicted
unfamiliar object/situation	something completely unrecognized by the observer OR a familiar object in an unexpected situation
familiar object	something has really changed in a familiar scene but you still 'see' what you expect to see
line of sight	it is difficult to judge the distance between two objects in the same line of sight
objects blending together	part of a foreground object appears to vanish because it 'blends in' visually with a background object (accidental camouflage) - this can happen with snow cover - also boldly coloured objects where their pattern breaks up their outline
uniform background	where there is a uniform background over most of someone's visual field it may compromise distance perception, promoting misperception
afterimage	where someone looks at a bright object then looks away and sees a 'negative' version superimposed on the background scene - though normally not difficult to notice, some situations (eg. monochrome night scene) may produce odd effects
reflection	size and distance of objects are routinely misjudged in reflections which can lead to misperception in certain circumstances (particularly where they involve featureless backgrounds)
misjudged distance	in certain circumstances may appear closer or further away than they really are eg. when they are covered in repeating patterns
sudden change in lighting	when a light is turned on or off it can produce a brief effect of apparent motion in an object when there is none in reality

source: Association for the Scientific Study of Anomalous Phenomena (ASSAP) article on Misperception

Factors to Examine for Misperception

Before an investigator can identify misperception, it is vital to understand the context in which it occurs. Misperception is not random—it emerges from the interaction between environment, witness expectations, and sensory limitations. Resources such as “visual substitutions,” “shadow ghosts,” and “ghosts – what we know” provide useful background, but the real challenge lies in applying these concepts in the field.

Traditional investigative methods—interviewing witnesses, inspecting sites, and attempting to recreate conditions—are a starting point, but misperception often requires more precise questioning and observation. Both casual witnesses and seasoned researchers are vulnerable to it, particularly in environments where lighting, distance, or expectation play tricks on the senses.

The table below highlights the key factors that investigators should examine when assessing whether an unusual sighting could be explained by misperception. While many of these details come from witness interviews, site examinations can also reveal conditions that encourage false impressions. Recognizing these patterns is not about dismissing experiences, but about sharpening our ability to separate perceptual error from possible paranormal phenomena.

Evidence factor	Looking for ...	Notes
Environmental factors
Illumination	Low and very high illumination levels	Object outlines may blend into other shapes in poor illumination; no color vision in low light
Distance of anomaly	Anomaly far away	At distance objects may not be recognised correctly
Direction of anomaly	Anomaly seen initially in peripheral vision	Anomaly may 'vanish' or 'change' when seen in central vision when caused by misperception
Duration of sighting	Anomaly only seen briefly	Objects 'glanced' are commonly misperceived
Partial anomaly	Anomaly partly obscured by other objects	An object may not be recognised if part of its shape is obscured
Observer movement	Head turned rapidly or observer in moving vehicle	Stationary objects may appear to move when the observer moves their head
Anomaly movement	Anomaly seen only briefly due to rapid movement - did it 'vanish'?	Similar effect to observer movement
Anomaly unrecognized	Object resembled something 'natural'
Anomaly 'changed'	Anomaly appeared to change 'unreasonably' eg. change shape	Could be optical illusion
Weather conditions	Fog, heavy rain, other weather causing poor viewing conditions
Witness factors
Witness distracted	Remember what you were thinking at the time just before the sighting	If witness was thinking about matters unrelated to current situation, may misperceive
Change blindness	Objects 'appear' / 'disappear' but not while in view	Witnesses aware of previous anomaly reports may misperceive along similar lines
Suggestion	Place appeared or felt 'spooky' before sighting - also local reputation	Surroundings may 'suggest' ghosts eg. cold, dark, humid, lonely, old building - local reputation for strangeness important too
Witness habituated	Notice likely background noises eg. birdsong, traffic, wind/rain, etc	Background view and noises no longer being sensed so stronger stimulus appears 'weird'

Source: ASSAP's article about Investigating Misperception

Testing Misperception

If one or more factors in the table above are present, it indicates the possibility that misperception could have taken place. It doesn't mean misperception necessarily took place. We don't see ghosts every time we enter a dark alley!

It is also possible to look for positive signs that misperception happened. Factors include:

Positive Signs of Misperception	What it means / Example
Seeing the anomaly but NOT the object that could have been misperceived	If the proposed misperceived object was in the same place as the anomaly, it should have been seen as well.
The anomaly sharing certain prominent features with the object that could have been misperceived	An example: a 'figure' had an arm projecting to the right and the misperceived object was a tree with a prominent branch to the right.
The witness recalling 'too much' detail of the anomaly for the viewing conditions	Avoid spurious detail from poor interview technique. Visual substitution can produce much more detail than real field observation because it comes from our own memory.
The anomaly 'vanishes' while (often momentarily) not in view	Misperceptions can easily 'break' but this usually happens when the viewer looks away. Expect statements like 'the ghost was clearly visible but when I looked away for just a second and then looked back it had disappeared.'

Source: ASSAP's article about Investigating Misperception

Closing Thoughts

Misperception is one of the most common—yet least understood—factors in paranormal investigation. While skeptics often use it as a blanket dismissal, careful study shows that it is far more nuanced. Detecting and documenting these subtle errors of perception takes patience, but doing so strengthens the credibility of every case.

Call-to-Action

As investigators, you can help close this research gap. Document your field observations in detail: note the conditions, witness states, environmental factors, and anything that might have influenced perception. Share your findings with fellow researchers. Each well-documented case brings us closer to separating the ordinary from the truly extraordinary.

More information:

- C.E.

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