Abscesses occur when an area of tissue becomes infected and the body's immune system tries to fight it. White blood cells move through the walls of the blood vessels into the area of the infection and collect within the damaged tissue. During this process, pus forms.
cognition cogÂ·niÂ·tion (kÅg-nÄ­sh'Én) n. The mental faculty of knowing, which includes perceiving, recognizing, conceiving, judging, reasoning, and imagining.
One of the earliest definitions of cognition was presented in the first textbook on cognitive psychology published in 1967. To get a better idea of exactly what cognition is and what cognitive psychologists study, letâs take a closer look at Neisserâs original definition.