Attention is a process through which we select certain information by filtering out many others that appear to be irrelevant at a given moment of time. It helps us gain knowledge of our internal and external world through our senses.

Attention has several important properties. Alertness refers to an individual's readiness to deal with stimuli that appear before her/him. For example, participants on the starting line of a race are in an alert state waiting for the whistle to blow.

Concentration refers to focusing of awareness on certain specific objects while excluding others for the moment. For instance, a student in a classroom concentrates on the teacher's lecture and ignores all sorts of noises coming from different corners of the school.

Search is a property where an observer looks for some specified subset of objects among a set of objects. For example, when you go to fetch your younger sister and brother from school, you look for them among innumerable boys and girls.

Attention also has a focus and a fringe. When the field of awareness is centered on a particular object or event, it is called the focal point of attention. When objects or events are away from the center of awareness and one is only vaguely aware of them, they are said to be at the fringe of attention.