| Abstract: |
Social media influencer marketing (SMIM) is now a dominant digital
communication strategy shaping consumer decision-making, yet prior SMIM
research remains theoretically fragmented and methodologically dispersed,
limiting a coherent understanding of how influencer attributes drive
behavioural outcomes. This structured literature review synthesises evidence
from 17 peer-reviewed journal articles published between 2014 and 2024. Guided
by Source Credibility Theory, the review analyses the roles of influencer
attractiveness, expertise, and trustworthiness as antecedents of perceived
credibility. Descriptive mapping, thematic synthesis, and contextual
comparison were used to consolidate key themes, study designs, variables,
mediators, and moderators. Across studies, attractiveness, expertise, and
trustworthiness consistently strengthen perceived credibility. Higher
perceived credibility is repeatedly associated with stronger consumer trust,
engagement, and purchase intention. Influencer-brand fit and disclosure
transparency emerge as critical determinants that condition campaign
effectiveness and shape how credibility translates into consumer responses.
The synthesis clarifies core credibility pathways in SMIM and proposes an
integrative framework to reduce fragmentation and guide future theory
development. Practically, the findings highlight the importance of aligning
influencer selection with brand fit and ensuring authentic, transparent
content. Key gaps include limited theory-building, narrow contextual coverage,
and heavy reliance on cross-sectional self-reports, indicating the need for
longitudinal and behavioural-data research to strengthen causal inference and
external validity. |