Which study procedure is most likely measuring or attempting to evoke the affective component of attitude?

The correct choice involves fantasizing about the positive aspects of losing weight, as this procedure directly taps into the emotional and affective components of attitude. The affective component of an attitude refers to the feelings or emotional responses we have towards an object, person, or concept—in this case, weight loss. By imagining the positive outcomes and benefits associated with weight loss, individuals engage in a process that can elicit positive emotions and reinforce their motivation.

Fantasizing about the positives stimulates feelings of hope, joy, and satisfaction, which are core to the affective aspect of attitudes. This emotional engagement can help align one's feelings positively towards the goal of weight loss, potentially making it more achievable.

The other options, while related to the concept of weight loss, focus on cognitive or behavioral elements rather than the affective component. Reflecting on past failed attempts can lead to feelings of frustration or disappointment, which does not evoke positive affect. Rating predicted success involves cognitive appraisal and estimation rather than emotional engagement. Participating in proactive strategies is a behavioral approach that may contribute to effective weight loss but does not specifically engage or evoke feelings or emotions linked to attitudes about weight loss.