TRA proposes that individual beliefs influence attitudes which will create intentions that will generate behavior. There are two major factors that determine behavioral intentions which are the person’s attitude toward the behavior and subjective norms. Attitude toward the behavior refers to the person’s judgment that performing the behavior is good or bad according to his or her belief. While the subjective norms are a function of normative beliefs that reflect the person’s perception of social pressures put on him or her to perform or not to perform the behavior in question.
TRA model
TPB is an expansion of the TRA. TPB includes the construct, perceived behavioral control to measure and account for the extent to which users have complete controls over their behavior. Perceived behavioral control relates to the extent to which the person believes that she or he has control over personal or external factors that may facilitate or constrain the behavioral performance.
TPB model
TAM pioneered by Davis advances the TRA by postulating that perceived usefulness (PU) and perceived ease of use (PEU) are key determinants that lead to the actual usage of a particular technology or system. Perceived usefulness is the degree to which an individual believes that using a particular system would enhance his or her productivity while perceived ease of use is the degree an individual believes that using a particular system would be free of effort.
TAM model
DTPB was formulated through combination