Tricks of the Mind

I found this website after researching why I saw little white orbs floating around in patters. It turns out that it is what is known as Sheerer's Phenomenon. I believed the list on this website should be gone over every time you believe a paranormal experience has happened, when in fact, it merely could be a trick of the mind.

www.parascience.org.uk...

The field of paranormal investigation, specifically the process of actively hunting for ghosts, can be at best an inexact science if indeed it can be classed as a science at all. At worst, it can provide the material for fully fledged flights of fantasy, even in the most apparently down-to-earth of characters. To this end, we present a brief overview of the most common misperceived events that may occur during an active investigation.

Belief and Expectation

The role of an investigator's expectations can colour their perception of events. Because of this we believe it is important for an investigator to be a "true" skeptic - neither a believer nor a disbeliever. Whilst it is important to approach an investigation with theories and background knowledge, approaching the field with strong beliefs one way or the other leaves the investigator open to the danger of misinterpreting events according to these set beliefs. It is as unconstructive to over explain events as having non-paranormal causes as it is to blindly believe that a phenomenon must have a paranormal cause.

Simple Misperceptions

Due to the unusual circumstances investigators find themselves in, for example it is unusual for anyone to sit motionless in the dark attending to any slight sound or feeling during their normal daily life, it can be easy to misperceive what are actually quite benign and common events. A commonly reported phenomenon is the sense of ghostly fingers running through one's hair. Whilst we must remain open to the possibility that this is indeed what is occurring, it must also be borne in mind that a common physiological process may also be at work. We have noticed on numerous occasions that an investigator has sat down in a darkened room, and removed an item of headgear for example a baseball cap or woolly hat, to make themselves more comfortable. Human hairs have touch receptors associated with them, and these are stimulated when the hair is bent. When the hat is removed, the hair, which has been bent over against the head, resumes its normal shape. This stimulates the touch receptors, and produces a sensation easily interpreted as ghostly fingers.

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The "Sense of Presence"

One of the most commonly reported phenomena is the sense of presence - the feeling that there is someone or something in the room that can't be seen. This can simply be due to a sense of expectation - in a reputedly haunted house the investigator expects, indeed sometimes almost wills, a presence to appear. Coupled with a state of heightened suggestibility - being aware of the haunted reputation of the building - a sense of presence can be induced quite easily.
The beliefs of the investigators mental set can affect his behaviour and perceptions. If he believes that he will experience a paranormal phenomenon, he will unconsciously perceive events according to that belief. These beliefs can cause him to misperceive events, even if in reality this appears illogical. We try to create the evidence to fit the belief.
Conditions of quiet and darkness allow the investigator to detect faint stimuli that are ordinarily masked - these are interpreted in accord with a person's expectations and fears - in an environment with a reputation for invisible presences the investigator's worries may transform innocuous sights, sounds, and feelings into hints of hidden menace. As an example, a simple draught through a room has been misperceived as a ghost passing through an investigator. If the same draught was felt in more innocuous surroundings, it would either not be perceived at all, as an unimportant stimulus, or it would be assumed to have a more normal cause, for example an open window. The fact that the draught was felt with no visual stimulus only increases the feeling of unease.
An example of these factors influencing perception occurred some years ago during an investigation when a sound subsequently discovered to be a bilge pump at a dock, was reported as being the "sound of a body being dragged". Expectation and belief transformed an innocent sound, whilst unusual and outside the investigator's previous experience, into something far more fanciful and sinister.
There are also physiological explanations for the experience of a sensed presence. Experiments by Michael Persinger in laboratory situations have shown that individuals with greater than normal metabolic activity in the temporal lobe region of the right hemisphere of the brain are more likely to report encountering invisible beings. It has been suggested that aspects of a person's own sense of self are generated in this brain region; when it becomes unusually active, the self-image of the right hemisphere intrudes upon the left hemisphere, which interprets it as the presence of an unseen external entity.
Another physiological cause that has been suggested for producing the sense of presence are extremely low frequency sound waves - infrasound. Exposure to infrasound has been proven to cause various physiological effects on the human body, including anxiety, shivering, breathlessness, and a feeling of an unseen presence. If a wave of 18Hz is present, the human eyeball can start to resonate with the wave, so causing a person to see hallucinations in their peripheral vision. These sound waves can be produced by electrical equipment, but may also be produced as a result of, for example, wind blowing through a window and down a corridor.

Pareidoloa

Another way that external stimuli may be misperceived is termed pareidolia. A common example is when we "see faces" in clouds. The human brain tries to make sense of the world around it, when it is presented with a stimulus it will try and match it to something it has encountered before, again with respect to the person's beliefs and expectations.

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Ideoretinal Light

This describes the phenomenon of flashes of light or colour that may appear in the field of vision in the absence of sensory stimulation. They can cover a wide range of optical phenomena, from simple lines and patterns, through so-called "wallpaper patterns", right up to full scenes. These effects are a form of entoptic phenomena.

Entoptic Phenomena

Entoptic phenomena are sensations produced by the structure of the visual nervous system. They can relate to perception of objects actually within the structure of the eye, a common example being "floaters" - bits of debris floating in the vitreous body of the eye. The vitreous humour is a jelly like substance that fills the eyeball. As we move our eyes, this jelly "sloshes about" within them, and as a consequence of this movement, and also the fact that the jelly shrinks with age, cells and fibres within the eye can break off. These cells and fibres cast a shadow on the retina, and as the eyes are moved they can be seen as semi-transparent, irregular lines floating across the vision - hence the name "floaters". If these cells break off from around the optic nerve, they can form a circular shape with a clear middle, reminiscent of the "orbs" and "lightballs" reported on digital photographic images. These floating objects can be misperceived as external objects, seen as outside the eye rather than within it.

Scheerer's Phenomenon

Light passes through several layers of retinal cells to reach the light-sensitive receptor cells - these layers are nourished by a capillary network of blood vessels. If a bright, steady light enters the eye (for example a light source in a dark room), it is sometimes possible to see streaking points of light and shimmering webs of light in the field of vision, caused by the blood flow in front of the receptors. Because the eyes are constantly in motion, either voluntary or saccadic scanning, a sense of motion may be imparted to these entoptic effects.

Awareness of Imagery

Imagery is the phenomenon of visual experiences in the absence of any visual stimulus from the outside world. An example of this is day-dreaming. If you can try and imagine a white, sandy beach, with clear blue skies, a beautiful blue sea with waves lapping at the shore. You should have been able to produce quite a clear mental image of this scene. There is some evidence to suggest that we use these sorts of mental images all the time. Think of when you have been driving a car and need to make a decision - should I overtake the car in front? You will use imagery to construct a mental picture of the consequences - you will not actually stop seeing the road, but your brain has created a mental image. We are unaware that this is happening - we wouldn't be able to function without it, but we also wouldn't be able to function if we were constantly aware of it. In the scenario of mild sensory deprivation (quiet and dark), it is possible to become aware of this imagery as there is nothing else to focus the conscious attention on. Because it is something not normally consciously perceived, it is possible to externalise this imagery and interpret it as something occurring external to the body, rather than produced within the mind.

For the complete list, please visit the website. I posted about half of the article here.