Beliefs define us and make us more human

Bertrand Russell observed that "believing is the most mental thing we do." Indeed, our beliefs define the world for us. Our thoughts and feelings, our actions and reactions, respond not to the world as it actually is but to the world as we believe it to be. Because of our beliefs, we brush our teeth or don't bother; we eat certain foods and avoid others; we worship one deity or another or none at all, and we rely on scientific medicine or homeopathy to cure our ills.
Even more important, our beliefs tell us who we are. They mark our place in the social world and provide a personal, autobiographical history that anchors us to various places and situations and events across our lifetimes. As a result, you may believe that you are a male university student, a female college teacher or a newspaper reporter.
You may believe that you are the same person who broke an arm after falling off a bicycle at age five, who played the Music Man in a high school play, and who now sits reading this. We generally take for granted that such beliefs are accurate, but when there is clear evidence that they are not, we may label them delusional. And when such beliefs wither away with the onset of dementia, people gradually lose knowledge not only of the world around them but even of themselves. They no longer know who they are.
While we generally trust our beliefs and they usually serve us well, they can be very vulnerable to error and distortion. To understand why this is so, it is important to examine how they form in the first place and how they can shift over time.
Our brains, of course, have no direct contact with the outside world, and our only information about what is going on outside comes from the wonderful array of sensors - eyes, ears, taste buds and so on - that developed when our bodies were taking shape in utero. These sensors collect data from the outside world and deliver it to non-conscious processes in the brain where it is processed and largely interpreted before being fed to our consciousness. By the time we are aware of it, the "data" have already undergone considerable modification. For example, we see colours, but colour does not exist outside our brains. It is only a subjective phenomenon. Similarly for sound: Our brains construct the subjective experience of sound in response to the waves of molecules that strike our eardrums.
And of course, we all know that our eyes can fool us at times.  While we may illusions as entertaining, they also provide an important message: Our perceptions of the world can be very misleading at times and can result in beliefs that are wildly inaccurate. It is not only perception that can lead to false beliefs. Errors of memory and the vicissitudes of learning and emotion can also distort what we become to believe. The various processes that feed into our beliefs constitute what I like to refer to as a Belief Engine.
The Belief Engine chugs away in the background, taking in information from the world outside, scrutinising its source, checking its compatibility with existing beliefs, subjecting it at times to logical analysis, and then effortlessly generating new beliefs and maintaining or modifying old ones. Most often, this occurs without the awareness of the "operator" - you or me.
 And, like a computer, our Belief-Engine brains comprise both hardware and software. We come into this world equipped with the basic hardware, although it continues to develop further over a number of years after birth. The "software," the programing, comes through interaction with our environment (parents, teachers, siblings, friends, the media, and the experiences of everyday life) and through the development of the thinking skills that we acquire as we grow up.
-Psychology Today
James E. Alcock, Ph.D., is Professor of Psychology at Glendon College, York University, in Toronto, Canada