“…This theory hypothesizes that positive emotions such as gratitude broaden the repertoire of thoughts, actions, and attention (Fredrickson & Branigan, 2005;Le Nguyen & Fredrickson, 2017), contributing to the development of long-term physical, psychological, social, and intellectual resources (Fredrickson, 1998(Fredrickson, , 2004aFredrickson & Branigan, 2005; see Figure 1). Despite the far-reaching impact of this theory (Fredrickson & Joiner, 2018), it has been labelled a descriptive rather than a 'mechanistic' framework and may be limited in its ability to identify causal mechanisms (Alkozei, Smith, & Killgore, 2017;Wood et al, 2010).…”