What is attention?
The idea of attention was inspired by human cognitive function. At any moment, the optic nerves in our eyes, the olfactory nerves in our noses, and the auditory nerves in our ears send a massive amount of sensory input to the brain. This is way too much information, definitely more than the brain can handle. But our brains have developed a mechanism that helps us to pay attention to only the stimuli that matter—such as a sound or a smell that doesn’t belong. Years of evolution have trained our brains to pick out anomalous sounds or smells because that was key for us surviving in the wild, where predators roamed free. In cognitive science, attention is defined as the cognitive process that allows an individual to selectively focus on specific information while ignoring other irrelevant stimuli.
Apart from this kind of instinctive attention, we are also able to control our attention by what we call focusing on something. You are doing it right now...