Sense perception

Having the right attitude and knowing the standards of evaluation are not enough to guarantee that one will always
succeed at critical thinking. Human beings are subject to a number of limitations and hindrances that forever get in
the way of our best intentions.
Aristotle advised that we should not demand
more certainty than the subject allows
(Nichomachean Ethics, I, iii.). That was good advice
2,500 years ago and it’s good advice today. Most of
the subjects that concern us in our daily
*“To doubt everything or to believe everything are two
equally convenient solutions; both dispense with the
necessity of reflection.” --Jules Henri Poincaré
lives are incapable of absolute certainty. The most we can hope for is a reasonable certainty that we’ve arrived at
the best possible beliefs. Infallibility and absolute certainty are beyond our reach. Think, for example, about the
source of most of our beliefs: sense perception. Each of the senses is limited in extent: Each sense has a threshold
beyond which we cannot perceive. We can extend those thresholds by using instruments such as telescopes and microscopes.
But those instruments have thresholds, too. Our instruments enhance our knowledge but they, too, are
limited.
Furthermore, each perception must also be interpreted. With each interpretation there is the possibility of error.
Each of us has been mistaken about something we thought we saw or heard. Although we often treat facts as if they
were infallibly certain, they aren’t. Facts are those things we don’t have any doubts about. We call something a fact
if we consider it grossly unreasonable to deny it. But, since our grasp of facts is based on sense perception, we
should not claim to know any facts with infallible certainty.
Apophenia and pareidolia
In statistics, apophenia is called a Type I error, perceiving patterns where there are none. Some people do not just
see birth marks on a lamb; they see the word “Allah” spelled out in Arabic and interpret this as a sign. They
spontaneously perceive connections and meaningfulness in unrelated phenomena. They see a mark on a pizza box
and are sure it is a pentagram, signifying that the pizza parlor is run by worshippers of Satan. According to
neuroscientist Peter Brugger, “The propensity to see connections between seemingly unrelated objects or ideas
most closely links psychosis to creativity ... apophenia and creativity may even be seen as two sides of the same
coin” (Brugger 2001).3
While such creativity may be desired sometimes, it can also lead us astray. Some people see patterns in such
things as the entrails of animals, the stars, thrown dirt or sticks, folded paper, the lines on the palm of the hand, and
so on. They believe that the patterns they perceive are magically connected to the empirical world past, present and
future. This belief is known as sympathetic magic and is the basis for most forms of divination. It is also the basis
for such practices as sticking needles into figurines representing enemies, as is done in voodoo. The pins and
needles stuck in a doll are supposed to magically cause pain and suffering in the person the doll represents.
Apophenia and magical thinking at one time may have represented a significant improvement in human
evolution, but these pre-scientific ways of seeing and responding to the world of perception can be major
hindrances to critical thinking and lead us to many illusory beliefs.
Pareidolia is a type of illusion or misperception involving a vague or obscure stimulus being perceived as
something clear and distinct (Schick and Vaughn 2001). For example, a water stain on a window or the
discoloration in tree bark is clearly perceived to be the Virgin Mary. While it is useful for any perceiving animal to
be able to quickly interpret vague or obscure stimuli, we must be careful or we will delude ourselves with our
interpretations, especially if others confirm them (see communal reinforcement, below). Pareidolia helps explain
such things as sightings of Elvis, Bigfoot, or the Loch Ness Monster. And it may explain many religious
apparitions and visions.  
Autokinetic effect

The autokinetic effect refers to perceiving a stationary point of light in the dark as moving. Psychologists attribute
the perception of movement where there is none to “small, involuntary movements of the eyeball” (Schick and
Vaughn 2001). The autokinetic effect can be enhanced by the power of suggestion: If one person reports that a
light is moving, others will be more likely to report the same thing (Zusne and Jones). Some, but not all, UFO
sightings are attributable to the autokinetic effect while perceiving bright stars or planets such as Venus (Schick
and Vaughn 2001).
Hypersensory perception, the Clever Hans phenomenon, and ideomotor action
Hypersensory perception (HSP) is what some people call intuition (Schick and Vaughn 2001). A person with HSP
is very observant and perceptive. She may be adept at reading body language or simply be more attentive to detail
than most people. She may pick up subtle behavioral cues unconsciously, cues that are also unconsciously given.
Because others are not so adept at reading such signs, someone with hypersensory perception may seem psychic.
Nonverbal influence can be quite profound and has been demonstrated in a number of psychological
experiments (Rosenthal 1998). One of the more interesting examples of nonverbal influence is the Clever Hans
phenomenon, named after a horse that responded to subtle visual cues when asked questions such as “What is 3
plus 2?” The horse would respond by tapping his hoof five times. He appeared to be capable of understanding
human language and doing simple mathematics. However, “Hans was responding to a simple, involuntary postural
adjustment by the questioner, which was his cue to start tapping, and an unconscious, almost imperceptible head
movement, which was his cue to stop” (Hyman 1989: 425). Hans’s master, William Von Osten, was unaware of his
own movements that were signaling the horse. Such unconscious movements are known as ideomotor action. The
term was coined by William B. Carpenter in 1852 in his explanation for the movements of rods and pendulums by
dowsers, and some table turning or lifting by spirit mediums (the ones that weren’t accomplished by cheating).
“Carpenter argued that muscular movement can be initiated by the mind independently of volition or emotions. We
may not be aware of it, but suggestions can be made to the mind by others or by observations. Those suggestions
can influence the mind and affect motor behavior” (Carroll 2003: 172). “The movement of pointers on Ouija
boards is also due to the ideomotor effect” (Carroll 2003: 172).
Inattentional blindness
So, we sometimes perceive things that are not there and sometimes we perceive things that are there, but we are
unaware of them. It may seem surprising, but we sometimes do not perceive things that are there right before our
eyes. Psychologists call this inattentional blindness. A number of studies have shown that if we are focusing our
attention on one thing, we may completely miss other things that are present. For example, a pilot has flown to see
a recently discovered crop circle near Stonehenge. After visiting the site, he flies back to the airport to refuel before
setting off on a trip that will take him back over the site he had just visited. On the return flight he notices another
crop circle near the one he had visited and swears that the new circle was not there just forty-five minutes earlier.
The new circle is very elaborate and could not have been produced by human hoaxers in such a short time. He
concludes that some mysterious force is at work. Perhaps, but it seems more likely that the pilot experienced
inattentional blindness when he was flying to the airport. He was focused on other tasks when he flew over the site
and didn’t notice what was right beneath him all the time.