The effect of visual complexity and congruity on consumer purchase intentions: the mediating role of fluency

The aim of this PhD thesis is to study the effects of visual complexity (simple versus complex images) on consumer purchase intentions. The thesis also explores the mediating role of fluency and the moderating role of congruity. To address the research aims, this PhD thesis relied on insights from aesthetics literature (Palmer et al., 2013), as well as fluency theory (Lee and Labroo, 2004; Reber et al., 2004), to propose a framework that tests and predicts consumers’ responses to visual stimuli. Specifically, the thesis employs three laboratory experiments, conducted in London at different times and days of the week. Study 1 investigates the effects of visual complexity (simple versus complex) on fluency, in terms of perceptual fluency (the ease with which people process the perceptual characteristics of a stimulus), conceptual fluency (the ease with which people understand the semantic meaning of a stimulus), and imagery fluency (the ease with which people imagine a stimulus). Study 2 explores the moderating effect of congruity (complex congruent versus complex incongruent images) on the relationship between visual complexity (simple versus complex images) and fluency. Finally, in Study 3, the relationship between visual complexity (simple versus complex images) and consumer purchase intentions is examined, as well as the mediating role of fluency (in terms of perceptual fluency, conceptual fluency, and imagery fluency). Across the three experiments, this PhD thesis demonstrates that it is easier for consumers to perceive, understand semantically and imagine simple images, in comparison to complex images (Study 1). Overall, by examining the relationship between visual complexity and the three dimensions of fluency, the study offers a concurrent account of the role played by visual complexity in metacognitive processes of fluency. Thus, the thesis is the first of its kind in explaining the relationship between visual complexity and types of fluency. Furthermore, the thesis highlights that congruity moderates the effects of visual complexity on fluency; specifically, complex congruent images are perceived as more conceptually and imagery fluent than complex incongruent images. It is important to note that when comparing the effects of simple and complex images, simple images are found to be more fluent than complex images (Study 2). This research reaffirms the findings relating to congruity and conceptual fluency and provides a first-hand account of the relationship between congruity and perceptual fluency, as well as imagery fluency. Finally, in Study 3, the findings demonstrate that the effects of visual complexity on purchase intentions are mediated through fluency. In this way the PhD thesis responds to Palmer and colleagues (2013) call for future research to examine the link between fluency and behavioural responses. Furthermore, taken together, the results of the three experiments offer several contributions to the literature by suggesting a model that explains consumers’ responses to visual stimuli in relation to purchase intentions, as well as the metacognitive experiences underpinning that relationship. The study also introduces several practical implications for the business world with regard to the way brands could use images to influence consumer purchase intentions.