Bem's self perception theory posits that they are formed by observing one's own behavior, while cognitive dissonance theory posits that they change when we perform behavior inconsistent with them.
Darwin was the first to theorize about them, defining them as a motor concept.  Fishbein and Ajzen developed a theory to explain their effect on action, while Sherif's social judgment theory posited a "lattitude of acceptance" to explain how they change.  In 1934 LaPiere demonstrated their lack of predictive power in a study of hotel manager's willingness to serve Chinese guests. Bem's self perception theory posits that they are formed by observing one's own behavior, while cognitive dissonance theory posits that they change when we perform behavior inconsistent with them. Greenwald and Banaji developed a test to detect their implicit variety, while Carl Hovland was the first to examine how pursuasion changes them. FTP, identify this social psychological construct which represents a person's like or dislike of an item.
Darwin was the first to theorize about them, defining them as a motor concept.  
attitude