There are other factors that affect this process. Our memory is stretched and warped like a rubber band to conform to our perception of reality. This affects witnesses, allows magicians to make a living, causes UFOs and white lights at the end of tunnels. Our memory can be warped because of any number of reasons. Memories can be implanted through suggestion as with traumatic experiences. To conform to reality, these seeds can grow in our minds and change how we perceive reality. In order to retain a sense of self, light, caused biologically during surgery, can be transformed into a religious experience. The mind changes its perception of reality in order to cope with the stress of surgery. It recalls from memory the comparison of a tunnel and other similar events. There are more minor examples of cognitive perception. A study done by Herbert Simon1 on what separates a chess master from a chess player. He demonstrated that masters viewed the pieces as units while amateurs viewed the pieces individually. This allows the masters to efficiently compare their perception of the board with their memory of past games.

  To add another trial, beyond making the connections between the visual register and the memories of the person behind them, there is visual cognition. Humans do not see everything at once - and yet we also do. Our eyes do not fix themselves in one place and see an entire image, instead, we see in combinations of two things - fixations and saccades. Fixations are the brief moments when we are looking directly at something and the fovea is trained upon it, while saccades are times in which we are technically blind, as the eye is moving too quickly to get any sort of picture from what it is seeing. Still, even though our perceptions should be of a thousand short, jerky movements, we see one long flowing picture - we percieve it all as one.

  Though there is no iron clad answer to how we achieve this, there is a theory, called the Integrative Visual Buffer theory. The main idea behind the theory is that we not only hold in our minds a picture of what we are seeing, but an idea of where that picture is relative to everything else. The image we currently 'see' is actually a composite of all the fixations we have made, organized by an understanding of where they are relative to everything else. Unfortunately, this theory has not been proven (which is likely why it remains a theory).

To understand the psychology of sound, we must first study the physics of sound. Sound is a series of waves projecting outwards from where the sound originated, and it travels at 340 m/s. The wave of sound is defined by two things - the amplitude, or height of the waves, and the frequency, or the inverse of the distance between peaks of waves.

Generally today, sounds are measured in decibels, which is actually a unit of the difference in intensity between two sounds, and is logarithmic in nature. However, as it is usually used, it is taken as the difference between the measured tone and the threshold of hearing. Intensity itself is proportional to the square of the amplitude and is measured in terms of power per area.

When the travelling waves that form the sound strike our ear, they cause the eardrum to vibrate. From there, they travel to the inner ear, then to the cochlea, where they are changed and translated into neural energy so that they may be interpreted.

There are two psychological dimensions of sound which are related to the physical dimensions of sound, known as pitch and loudness. They generally express frequency and amplitude, respectively. Pitch is approximately proportional to the logarithm of frequency, though this breaks down at the edges of the scale, while loudness generally increases with the intensity of the sound. The difficulty is that loudness is very much subjectively interpreted, as there are certain sections of sound (200-5000 Hz, which is the frequency of human speech, and especially 2000-4000 Hz, which is about the resonant frequency of the auditory canal) which are heard as louder than others.

An element of interest within the dimension of pitch is that of "perfect pitch", an unexplained section of auditory perception. Perfect pitch is the skill by which a person may listen to a particular pitch and be able to give the musical note name to go along with it. This is beyond most of us, as we are generally limited to only speaking of relative heights of notes.

A pure tone, such as that as one would tune one's instrument to, can be created either electronically or physically by the use of a tuning fork. A pure tone is one with only one sinusoidal component, uncorrupted by harmonics. In the musical scale used today, notes are arranged in successive frequencies, with each eight note octave doubling the frequency.

There are two perspectives on pitch which one should be aware of, two theories. One theory places pitch as a one dimensional phenomenon - the other places it as a continually cyclic helix. The second theory has been proposed for the simple reason that some people, especially trained musicians, percieve tones as a cycle which repeats on the octave. This idea uses two terms to describe pitch - height and chroma.

This second theory is weighed out by the existance of the Shepard Tone, discovered by Roger Shepard. This is a situation when two tones, a major seventh apart, sound as if the second increases in pitch while decreasing in tone. This is caused because the 'partials' of the sound rise above and below the 'fundamental' - causing one to be confused as to whether the tone is ascending or descending.

 
Footnote: 1. Herbert Simon won a Nobel Prize and did the aforementioned research at Carnegie-Mellon University in Pittsburgh.