The Power of Positive Thinking in 1955. Meyer writes that "The Power of Positive Thinking" provides partial awareness to the limitations of the readers but does not supply the necessary self-confidence to overcome those limitations. He proceeds to compare Peale to a con man saying that the problem with Peale lies in the “paltriness of the confidence he preached. He did not really try to fool you into thinking you could do much, or be much, or live much. He did not make you aware of greater heights any more than of greater abysses.” Psychologist Martin Seligman, former APA president and founder of positive psychology,
Positive psychology for someone of low skills results in a state of anxiety; insufficient challenge for someone highly skilled results in boredom. Research in positive psychology, well-being, eudaimonia and happiness, and the theories of Diener, Ryff, Keyes and Seligman cover a broad range of topics including "the biological, personal, relational, institutional, cultural, and global dimensions of life". A meta-analysis on 49 studies in 2009 showed that Positive Psychology Interventions (PPI) produced improvements in well-being and lower depression levels, the PPIs studied included writing gratitude letters, learning optimistic thinking, replaying positive life experiences and socializing with others. In a later meta-analysis of 39