You've probably heard of pattern recognition - the ability to recognize faces, objects music, or other sensory inputs with only a few pieces of the whole. For example, if you're old like me, you'll remember a game show from the 70s called Name That Tune. In one of the show's segments, contestants would "bid" against one another, betting on their ability to name a tune in a certain number of notes (to be fair, they also typically had a clue that provided some obscure fact about the song). The typical number of notes bidders would stop at was three notes. Once the lowest bid was achieved with the opponent saying, "Name that tune," (how meta is that?), then the piano would play two or three notes of the melody, and it was up to the lowest bidder to come up with the name of the song. More often than not, the contestant was successful.

This is one example of pattern recognition, and as a musician it makes a lot of sense to me. My son plays several musical instruments, including percussion. This leads him to beat out rhythms of songs on available surfaces frequently, and I am usually fairly successful at recognizing what song he is "playing." I can also hear a series of chords or a chord progression and know what tune it is associated with, regardless of whether I hear the melody.

I'm telling you this not to brag that I'm some kind of a musical savant, but rather to illustrate that, at least as far as music goes, I have pretty decent pattern recognition. Minus full auditory input, I can easily fill in the blanks and come up with an entire song in my brain.

Another form of pattern recognition with which you might be familiar is understanding a written message that uses only consonants, or even just uses beginning and end letters. Pattern recognition easily allows you to fill in the blanks to read a coherent word or phrase from the letters available, especially if you have a context for the message.

My point is this: given some sensory input that is missing pieces, our brain easily fills in the blanks. You may hear of this referred to in paranormal circles as matrixing (seeing faces or figures in random inputs) or pareidolia (usually making words from random sounds - such as hearing a random foot scuff as a whispered EVP). 

Our brain seeks to organize stimuli in ways we can understand. It fills in the blanks when stimuli is ambiguous, unfamiliar, or incomplete. When sensory stimuli conflicts (such as a weird sound coming from a known object), our brain may rearrange information in order to resolve those conflicts. All of this happens in an instant and we have no conscious awareness of the process. Instead, once our brain has filled in the missing information, it's nearly impossible to convince us our impressions are incorrect.

How does our brain fill in the blanks? Research suggests it does so by grabbing data from two types of memory: short term and long-term. We also filter in cultural expectations and data. This means that we will most likely resolve incomplete or conflicting sensory data by perceiving what we expect to sense. 

How does this affect perceived paranormal phenomena? Consider the conditions under which many people report paranormal phenomena. Some common elements in many reports include:

• Subject was tired or stressed.
• Phenomena was fleeting.
• Lighting conditions were low or changing (flickering of a television, turning lights off within the past ten minutes, eyes adjusting to light or dark).
• Subject was absorbed in another task at the time or deeply focused.
• Subject observes phenomena out of corner of their eye or when quickly turning his or her head.
• Subject was in an unfamiliar situation or location.

While sensory misperception may be a common logical explanation for eyewitness reports of paranormal (both from paranormal researchers and the general public), it doesn't necessarily mean all reported paranormal experiences are attributable to it. It is important to keep in mind when evaluating your own experiences, as well as those of other paranormal eyewitnesses.