The Plymouth Student Scientist

Document Type

Psychology Article


Extraversion as both a personality trait and state has robust links with well-being; extraverted state, or behaviour, is sufficient to increase positive affect (PA) regardless of disposition. However, examining extraversion more closely at the aspect and facet level has, to date, yielded mixed results for this relationship. This study sought to clarify extraversion’s impact on psychological well-being (PWB) and positive affect by investigating state and trait assertiveness as one aspect of extraversion (next to enthusiasm; DeYoung et al., 2007). It was hypothesized that this aspect specifically contributes to several PWB outcomes at the trait level, but not at the state level if well-being outcomes increase in high trait-assertive individuals only. Participants (N = 28) engaged in an embedded discussion task to induce PWB and PA state outcomes by means of instructions to behave assertively or authentically (control). To then quantitatively measure and report participants’ levels of traits and well-being states, several questionnaires were administered directly before and after the discussion task. Results showed that overall, Assertiveness (trait and state) was unrelated to most PWB outcomes and PA; however, assertive behaviour led to surprisingly lower environmental mastery compared to the control group (p = .031), which is likely explained by an interaction with low trait assertiveness characterising most of the assertive condition. Trait interactions with assertive behaviour were also visible, though not uniform, for within-groups increases in environmental mastery, self-acceptance, and PA. Limitations and implications for state-trait isomorphism, the Whole Trait Theory, and the general extraversion-wellbeing relationship are discussed.

Publication Date


Publication Title

The Plymouth Student Scientist





First Page


Last Page




Deposit Date

December 2022

Embargo Period




Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.