According to Wikipedia - Abstraction is the process of reducing the information content of a concept, typically in order to retain only information which is relevant for a particular purpose. For example, abstracting a premiership football to a ball retains only the information on general ball attributes and behavior. Similarly, abstracting an emotional state to happiness reduces the amount of information conveyed about the emotional state.
This photograph is attributed to gautamnguitar, and is posted on Flickr with a Creative Commons license.
Note: This post was originally posted on my blog at http://www.adaptivelearningonline.net