An implementation intention is a self-regulatory strategy in the form of an "if-then plan" that can lead to better goal attainment, as well as help in habit and behavior modification. It is subordinate to goal intentions as it specifies the when, where and how portions of goal-directed behavior. The concept of implementation intentions was introduced in 1999 by psychologist Peter Gollwitzer. Studies conducted by Gollwitzer in 1997 and earlier show that the use of implementation intentions can result in a higher probability of successful goal attainment, by predetermining a specific and desired goal-directed behavior in response to a particular future event or cue. History The concept of implementation intentions originated from research on goal striving throughout the late 1980s and 1990s. Developing research suggests that "the correlations between intentions and behavior are modest, in that intentions account for only 20% to 30% of the variance in behavior." Strong intentions ("I strongly intend to do X") were observed to be more often realized than weak intentions. Past behavior still tended to be a better predictor for a person's future behavior when it was compared to goal intentions. The research also suggested that the weak intention-behavior relation is a result of people having good intentions, but failing to act on them. This inspired a growing body of research to help determine ways in which peoples' good intentions could be made more effective in accomplishing desired goals. Emerging research proposed the notion that successful goal attainment is in part attributable to the manner in which goal setting criteria are framed. For example, a person will perform better when set goals are challenging and specific as compared to goals that are challenging but vague (known as the goal-specificity effect). Emerging research also suggested a goal-proximity effect (wherein proximal goals lead to better performance than distal goals). The strategy of implementation intentions was developed on the basis of these findings. Concept People generally have positive intentions, but often fail to act on them. The question is how to ensure that the set goal intentions will reliably lead to the desired goal-directed behaviors, and subsequent attainment of those goals. Implementation intentions offer a practical solution for such a problem. Achieving one's goals requires that certain goal-directed behaviors be instituted, but people are often unsuccessful in either initiating or maintaining these behaviors. The problems of initiating and maintaining goal-directed behavior can be addressed by using the implementation