Ever wonder what cognitive science really is useful for? How about the application software that you are using right now? Do you think the designers and programmers come up with these just to confuse you? (well, sometimes that may be true.) Cognitive science, or at least the cognitive psychology (or CP) part of it aids in development of user interfaces and the human-computer interactivity or HCI. CP is used to expose all the obviousness behind human thinking. It helps predict the actions that are required to perform certain tasks, especially when it pertains to the computer. Since the computer has limited resources for behaviour (unlike the human), algorithms must be in place to anticipate human behaviour. This is where the cognitive sciences can flourish...not just in psychiatric wards or the psychiatrist's office. Actual use of such information can be limitless.

Cognitive Science is the endeavour to model thought processes and cognitive representations (and the subsequent intelligent behaviour that arise from them) in purely scientific terms. Currently, the main focus of Cog. Sci. is to resolve the behavioural and cognitive levels of mental activity - the biological aspect is not given as much attention, because we currently lack the tools to investigate it thoroughly. Cog. Sci. has very strong links with Linguistics and Artificial Intelligence (Chomsky has a lot to say about the subject). It's currently quite a young discipline, with the potential to branch off in several directions and to alter its objectives and stance on several key issues as advances in its related fields filter through.

If the human brain was simple enough for us to understand, we'd be too simple to understand it.

During the 50s and 60s, the interest in psychology about the thought process changed with the appearance of computers. This invention forced the scientists to study problem solving and basic mental processes (like memory, language, perception, etc.) Looking at a insanely complex computer was like looking at the insanely complex brain. Cognitivism was born.
Cognitive comes from latin cognitum, which means "knowing".

For psychologists using the cognitive perspective, in order to understand how humans use language, common sense, social values and emotions, they must study the ways humans select and organize social informations. Clearly, what do we do with all the informations we receive. For personal feelings, they have to find the origin of the thoughts, memories and and things like that.
But "cognitivists" don't need to use Freudian introspection for that. These scientists study mental processes through observable behavior.
An exemple:
Some scientists ask someone to memorize a list of words. Depending on which words he will remember and which ones he will forget, the psychologists will be able to study the process of memorization (like the way words are 'packed' in the brain, by meaning or sound, a bit like a computer).

Cognitive perspective proved that perceptions and interpretations of a human can influence on someone's acts and feelings. We are all searching for a " meaning of life" or why we are feeling sad or happy right now, etc. Another example:
You walk on the street, look at some hip teenager and the young boy immediately punches you on the nose. Freud would say that it's because his father punched him a lot when he was a child (ok, I know, I'm simplifying it) but cognitivists say the boy did this because he interpreted your look as an aggression. They would study how his interpretation of the event influenced his actions and thoughts.

Some famous psychologists for the cognitive perspective:
Jean Piaget
Alfred Binet
Howard Gardner of Harvard