Seligman et al. (2005) also examined other self-guided exercises. For example, individuals were asked to write down three things that went well each day for a week and describe their causes. This activity led to well-being improvements that continued for 6 months (the longest period examined.) It can involve a mixture of judgments J1, J2, and L3, again directing a person’s thoughts to positive aspects of his or her situation. That optimistic perspective is also required in exercises that ask people to reflect on their future “best possible selves,” making the assumption the life has gone as well as it could. King (2001) asked undergraduate students to write narrative descriptions of their best possible futures for 20 minutes each day for 4 consecutive days, and Sheklon and Lyubomirsky (2006) obtained that written reflection once and asked students to repeat the exercise at least twice over the next 4 weeks. A significant increase in positive affect was found in both studies, and King (2001) also reported an increase in composite well-being after 3 weeks. However, follow-up checks after 4 weeks by Sheldon and Lyubomirsky (2006) indicated that in their study the benefit was only short-lived. They pointed out that in their study the benefit was only short-lived. They pointed our that the magnitude of impact was likely to depend on the extent to which a person continues with the activity over a period; repeated positive thinking may be more beneficial than merely a single episode. In their study and in the research by Seligman et al. (2005), continued exercising rather than merely a short-term activity was associated with greater happiness.