In his 1967 paper, Arbitrary and Natural Reinforcement , Charles Ferster proposed classifying reinforcement into events that increase frequency of an operant as a natural consequence of the behavior itself, and events that are presumed to affect frequency by their requirement of human mediation, such as in a token economy where subjects are "rewarded" for certain behavior with an arbitrary token of a negotiable value. In 1970, Baer and Wolf created a name for the use of natural reinforcers called "behavior traps".  A behavior trap requires only a simple response to enter the trap, yet once entered, the trap cannot be resisted in creating general behavior change. It is the use of a behavioral trap that increases a person's repertoire, by exposing them to the naturally occurring reinforcement of that behavior. Behavior traps have four characteristics:
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 studies with 6,139 participants in 2012, the outcomes were positive. Three to six months after a PPI the effects for subjective well-being and psychological well-being were still significant. However the positive effect was weaker than in the 2009 meta analysis, the authors concluded that this was because they only used higher quality studies. The PPIs they considered included counting blessings, kindness practices, making personal goals, showing gratitude and focusing on personal strengths. 
Given the number of tasks facing an incoming administration, it is no surprise that Trump’s news coverage during his first 100 days in office touched on an array of topics (see Figure 2). Immigration was the most heavily covered topic, accounting for 17 percent of Trump’s coverage.  Health care ranked second (12 percent), followed by the terrorism threat (9 percent), and Russia’s involvement in the 2016 election (6 percent). Presidential appointments, global trade, Trump’s family and personal life, and the economy were the other topics that received 4 percent or more of the coverage.