We here at the Skeptic sometimes wish we could have more intimate contact with the subjects of our entries.  Sometimes, it's because we think the people in question actually have something of some scientific use to offer.  Far more often, it's because we want to make absolutely sure that these people are being serious.

This entry falls into the latter category.

A woman named Donna Higbee begins her article-in-question thusly: 

In the summer of 1994, I became aware of a very strange 
phenomenon, human spontaneous involuntary invisibility, 
which was apparently happening to people in the U.S. 

That's OK, I had to read it again just to make sure, too.  What's extra frightening is that people actually claim to have been the victim of Human Spontaneous Involuntary Invisibility 
(referred to as HSII from now on).

Mrs. Higbee begins her research with a few examples of what she is talking about, although the name pretty much describes it:

...Vera in Ventura, California, who tried to get assistance 
in a post office, only to be completely ignored by other 
customers and the postal clerk. I have kept in touch 
with Vera and she has had other apparent invisibility 
experiences in stores and other public places. Sheila 
in Roanoke, Texas, continues to have invisibility 
experiences, some of which have occurred in 
restaurants and at the airport. Glenda in Fort Worth, 
Texas, has had these experiences occur in a 
cafeteria and a movie theater.

We are given no description of these women, physical or otherwise.  It is an unpleasant fact of society that some people are simply ignored in social situations.  We are not privy to the details of these cases, so a cursory examination is all we can give it.  Suffice it to say that simply because everyone around you pretends that you don't exist does not mean you are invisible.

In most cases, according to Mrs. Higbee, the invisibility is accompanied by an "inaudibility," as well.  People are incapable of seeing or hearing the victim. The case of Jean, below, is a good example of most of the cases of HSII: 

Jean in Tucson, Arizona, wrote me of her experiences. 
She has had them occur in the library when she attempted
to check out books and in clothing stores. The following 
is a quote from her letter, showing the humor with which 
she deals with these occurrences. "I've had this happen 
in stores, in restaurants, and many places. I remember 
joking to a friend of mine one time that I felt like I could 
walk into a bank, help myself to a pile of bills and no 
one would ever see me because I was invisible. There is no 
physical reason why I should be. I'm taller than average 
for my sex and age group (I'm fifty-five years old and 5'9"),
referred to as good-looking, and I've always worn my hair red. You wouldn't think a tall woman with red hair, high heels in a
purple dress and dangle earrings would be invisible, would you?"

No, but depending on her personality and/or bearing, I could definitely see myself ignoring her.  And if this happens as often as she says it does, she might want to look into a good 
deodorant. 

 ...from a thirty-seven year old man, Peter in Gloucestershire,
England, who was at a private party in 1987. He walked 
upstairs to use the bathroom and was followed by a 
woman who also wanted to use the bathroom. The 
woman motioned for him to go first and she stood 
outside the door to wait her turn. Peter used the 
bathroom, opened the door and walked out into 
the hallway, closing the door behind him. He went 
on down the stairs and walked over to some friends 
and started talking to them. They all ignored him 
completely. He though they were playing a joke on 
him, so he walked away and found his girlfriend and 
asked her for a cigarette. She, too, acted like she didn't
see or hear him. Peter was getting angry by this time and 
thought the joke had gone too far. He decided to walk 
back upstairs and catch the woman coming out of the
bathroom and ask her for a cigarette. "...I walked back 
up the stairs and, on reaching the bathroom landing, 
I came across the girl again who was standing outside 
the bathroom door, clearly still waiting for me to come 
out. When she saw me, her face dropped in surprise 
for clearly she thought that I was still in the bathroom."
Peter returned to the party downstairs and everything 
was normal again and he was able to be seen and 
heard. When he questioned his friends and girlfriend 
as to why they had ignored him, they all swore that 
they had never seen or heard him. Obviously the 
woman upstairs had not seen him come out of the 
bathroom and go downstairs. 

This is a very detailed story and an excellent example.  Is it not apparent to you, faithful reader, that poor Peter was the victim of a particularly insidious practical joke, and that the woman at the bathroom was simply distracted
when he emerged?  And if she wasn't distracted, wasn't she the slightest bit amazed, frightened or intrigued by the bathroom door opening and closing by itself? Also, alcohol (and whatever else was being distributed) tends to reduce one's attention span enough so that an intoxicated woman might not be aware of someone exiting/entering a bathroom at a party. 

An excellent treatise on the ups and downs of being invisible is H.G. Wells' The Invisible Man, in which a scientist manages to make the cells of his body transparent.  In it, Wells highlights some of the difficulties of being invisible.  One of the most striking and yet most obvious examples is how difficult it is for an invisible person to walk about with visible people...since they can't see him, they don't walk around him.  One would think, bearing this in mind, that Peter would not be able to navigate the party without bumping into a lot of people.  Since this presumably did not happen, one must doubt the accuracy of his story. 

Yesterday, we examined Donna Higbee's reports on what's called Human Spontaneous Involuntary Invisibility.  For more information, read yesterday's entry.  It will make this a lot more interesting.  Now, onto how Mrs. Higbee explains this stuff...

First, she gives us a bit of Indian spirituality, with a lesson from an early Indian writer named Patanjali:

"a direct contact with the light of the eyes no longer 
existing, the body disappears." The light engendered 
in the eye of the observer no longer comes into 
contact with the body that has become invisible, 
and the observer sees nothing at all.

This is obviously not true, since light does not come from the observer's eye.  Also, the density differences between a body and the air would reveal the invisible man, much like an ice cube in water. 

She also visits the Old School of spiritualism:

Another offshoot of the Rosicrucian
fraternity, the Hermetic Order of the Golden Dawn, 
left manuscripts describing the Ritual of Invisibility. 
These manuscripts talk about surrounding yourself 
with a shroud, which is described as looking like 
"a cloud." It is said that Madame Blavatsky, of
the Theosophical Society, witnessed this invisibility 
for herself and was actually given the secret, 
thereafter accomplishing this for herself on several 
occasions in front of witnesses. The literature on 
the Spiritualists in the U.S. shows that there is 
no doubt they, too, knew about the cloud and 
its creation. 

The "literature" on Spiritualists shows overwhelming evidence that they were nothing more than con-men looking for a buck.  There are notable, unexplained examples, but they are too few to constitute any kind of authoritative study.

She also offers a "scientific" explanation:

When spiritual essence gathers into very minute 
focal points of electrical charge (due to certain conditions),
we have the creation of electrons. Science reports that 
such a cloud of free electrons will absorb all light 
entering it; it will not reflect nor refract light waves, 
nor are light waves able to pass through a human being.
Consequently the observer’s eye sees nothing there 
and the person surrounded by such a cloud is invisible.
Since light is necessary for human sight, when there 
are no reflected or refracted light waves bouncing 
off a person and hitting the observer’s retina, the 
person is not able to be seen and is not visible 
under normal circumstances.

One needs only a basic knowledge of science to know that this is bunk; light that is absorbed completely does not make the object invisible.  Invisible is essentially transparent.  True invisibility allows for the light bouncing off of the objects behind the subject to somehow divert 
around or go through the subject and be received by the viewer's eyes.  A human-sized space where no light is reflected is seen as pitch-black...the opposite of the classic description of invisible. 

The article soon degenerates into groundless speculation, as many such articles do:

I find it interesting that the people having these invisibility 
experiences seem to be people with higher than average 
psychic abilities. Possibly they are able to traverse 
other dimensions and command natural forces, knowingly 
or unknowingly.

First of all, she cannot have any evidence of psychic abilities, at least not reliable evidence, because the very existence of psychic abilities is still in doubt.  The same is true for the dimensions she refers to. 

To close this rather long entry, we'd like to put forth our Tests for Invisibility, just in case you find those around you pretending that you do not exist.  We hope we can be of help!

TESTS FOR INVISIBILITY

1) Make certain to look for a shadow!  If you cast one, you're not invisible! 

2) Try making funny faces at a nearby child and/or innocent bystander.  In the latter case, you might want to try deeply personal attacks against the bystander's mother.  If the bystander's fist connects with any part of your torso or head, you're probably not invisible.

3) Try to remember whether or not you've angered your present company in recent weeks.  If you have, there's a good chance they're ignoring you. 

4) Are you easily angered and/or saddened by innocent jibes from your friends?  Are you gullible to the point of idiocy?  Do you take criticism just a little too personally?  If so, you might be the victim of a practical joke.

5) Are you currently under the influence of a 
hallucinogen or other mind-altering drug?   They 
cause strange effects in the mind of the user, and may explain a lot of the weird things happening to you.

6) Do you have an especially horrid physical 
appearance?  Do you have a particularly angering/annoying personality?  See Test #3.