Nutritional effects on consumer choice behavior : investigating the influence of caffeine on the attraction effect, compromise effect, and choice deferral

Abstract

“Tell me what you eat and I will tell you what you are” (Brillat-Savarin, 1825). It is no surprise that nutrition significantly impacts the human body. Most basically, an unhealthy diet, which is a key risk factor driving worldwide death and disability rates (Forouzanfar et al., 2015), leads to an unhealthy body. Accordingly, various methods have been implemented to assist humans in their nutritional choices, highlighting healthy over unhealthy foods (Lobstein & Davies, 2009). Regardless of the nutritional information provided, consumers oftentimes are unaware of the physiological and psychological impact of their diet or are even willing to accept the health risks involved with the consumption of unhealthy nutrition. This especially holds for psychostimulants, which have globally established themselves within the regular human diet. In the US alone, the psychostimulant nicotine is involved in more than 480,000 deaths annually in form of cigarette smoking, while additionally incurring smoking-related costs in excess of $300 billion per year (Centers for Disease Control and Prevention, 2022). An even more prominent psychostimulant, namely caffeine, has established itself as a relevant dietary aspect within western societies, with the US population’s mean daily consumption at 2.2 mg/kg body weight/day (Mitchell, Knight, Hockenberry, Teplansky, & Hartman, 2014). As caffeine is the most consumed psychostimulant worldwide (Fredholm, Bättig, Holmén, Nehlig, & Zvartau, 1999; Varani et al., 2005), the interest regarding its physiological impact, including toxicity due to habitual use (Reyes & Cornelis, 2018), is increasing for both public and scientific stakeholders. Related problems that have been discussed regarding the risks of caffeine consumption include dangers of energy drink overuse (Rath, 2012; Reissig, Strain, & Griffiths, 2009), interaction of caffeine consumption with alcohol consumption (Ferreira, De Mello, Pompéia, & De Souza-Formigoni, 2006; Sweeney, Meredith, Evatt, & Griffiths, 2017), caffeine addiction (Budney & Emond, 2014; Jain, Srivastava, Verma, & Maggu, 2019; Olekalns & Bardsley, 1996) and caffeine intoxication (Kerrigan & Lindsey, 2005). The influence of caffeine has been researched in various fields, including but not limited to physical sports performance (Del Coso et al., 2014), health (Nawrot et al., 2003), pregnancy (Qian, Chen, Ward, Duan, & Zhang, 2020), subjective time perception (Arushanyan, Baida, Mastyagin, Popova, & Shikina, 2003), and driving safety among truck drivers (Heaton & Griffn, 2015). Caffeine consumption has especially shown to influence important aspects of human behavior strongly associated with the human central nervous system (CNS) and accordingly the decision-making process. Consuming the CNS stimulant has indicated significant improvement in cognitive capabilities such as choice reaction time (Lieberman, Wurtman, Emde, Roberts, & Coviella, 1987), visuo-spatial reasoning (Jarvis, 1993), and attention (Heatherley, Hayward, Seers, & Rogers, 2005). Furthermore, caffeine has been revealed as a driver contributing towards the experience of feeling or emotion, namely affect. Studies have reported caffeine to increase arousal levels (Barry et al., 2005), improve arousal vigilance (Sanchis, Blasco, Luna, & Lupiáñez, 2020) and to benefit mood (Haskell, Kennedy, Wesnes, & Scholey, 2005). The impact of the physiological and psychological state of human beings and its influence on consumer perception and behavior has been a topic of interest in recent literature (Dai & Hsee, 2013; Lichters, Brunnlieb, Nave, Sarstedt, & Vogt, 2016a; Madzharov, Block, & Morrin, 2015; Masicampo & Baumeister, 2008). An under-researched topic, however, is the influence of caffeine on consumer purchase behavior. Due to the importance of cognition’s and affect’s involvement in the decision-making process, inspecting the link between the CNS stimulant and human purchase decisions should be considered a step towards better comprehending the consumer’s decision-making process and its underlying neurobiological origins. Improving to comprehend this process with an interdisciplinary approach may offer insight towards appreciating contextual settings (i.e. context effects) in which caffeine may manipulate the consumer’s decision-making ability and to which degree caffeine consumption may influence choice deferral. To investigate caffeine’s influence on consumer behavior, my thesis implements an array of placebo-controlled double-blind protocols with the intent to manipulate the participants’ levels of cognitive and affective capabilities before conducting a series of realistic product purchase tasks. Specifically, I investigate the degree to which caffeine consumption impacts purchase decisions in context sensitive scenarios and choice deferral. In an attempt to better comprehend their underlying mechanisms of consumer decision making (e.g. Lichters et al., 2016a; Masicampo & Baumeister, 2008), my research aims at contributing to existing literature having investigated the physiological states influencing context effects and choice deferral. In line with previous research (Lichters et al., 2016a; Lichters, Müller, Sarstedt, & Vogt, 2016b), I evaluate the neuropsychological processes driving context effects and choice deferral by investigating caffeine’s influence on decision-making in purchase scenarios entailing economic consequences (i.e., participants had to pay in exchange for products). The initial chapter of my thesis will focus on the principles of the two most prominent context effects, namely the attraction effect (AE), also referred to as the asymmetric dominance effect, and the compromise effect (CE), which both feature prominently throughout various recent articles of high ranking marketing journals (e.g, Farmer, Warren, El-Deredy, & Howes, 2017; Hadar, Danziger, & Hertwig, 2018; Liao, Chen, Lin, & Mo, 2020). The phenomena describe consumer behavior that deviates from axioms we take for granted in rational choice theory (Huber, Payne, & Puto, 1982; Simonson, 1989; Simonson & Tversky, 1992) and have been replicated in various settings (Lichters et al., 2016a; Milberg, Silva, Celedon, & Sinn, 2014; Neumann, Böckenholt, & Sinha, 2016; Simonson & Nowlis, 2000). While the underlying mechanisms of the CE are consistently associated with cognitive processes (Chang & Liu, 2008; Dhar & Gorlin, 2013; Lichters et al., 2016a), previous research suggests the AE to result from an impulsive decision-making style (Hedgcock & Rao, 2009; Mao & Oppewal, 2012; Pocheptsova, Amir, Dhar, & Baumeister, 2009). However, recent literature is shifting the narrative towards the AE resulting from a deliberate thought process (Hadar et al., 2018; Lichters, Bengart, Sarstedt, & Vogt, 2017). The second chapter of my doctoral thesis establishes the foundation for the hypotheses generated in chapter three. I first provide a general overview of caffeine before focusing on the physiological and psychological impact the psychostimulant has on the CNS and thus influences human behavior. Next, I combine the neuropsychological impact of caffeine on regions within the human CNS with the underlying mechanisms of context sensitive choice behavior to develop the hypotheses evaluated in the following studies. Prior to assessing the influence of caffeine on consumer choice behavior, chapter 4 will briefly address the limitations of context effect experiments (Frederick, Lee, & Baskin, 2014; Yang & Lynn 2014) while discussing guidelines suggested by Lichters, Sarstedt, and Vogt (2015) to improve the quality of experimental context effect research. I will review current literature evaluating the quality of recent experimental context effect research and to which degree the suggested guidelines made by Lichters et al. (2015) have since been implemented into experimental research published in high-ranking marketing journals. In the following chapters I present the conducted experiments evaluating the stimulant’s impact on decision-making within alternating experimental designs. Over three studies, caffeine will be administered orally by adding the substance to a decaffeinated coffee beverage or soft-drink, which was administered a caffeine dosage of 200 mg for the treatment group. This amount equals the caffeine dosage of 2.5 cans (250ml) of an energy drink such as RedBull® or 1.25 of Starbucks® ‘short’ coffee servings (Mackus, van de Loo, Benson, Scholey, & Verster, 2016). Thus, the administration procedure enabled a clear distinction between caffeine administration and lack thereof in a realistic setting. Aligning with previous studies examining psychological and physiological states influencing consumer decision making (Lichters et al., 2016a; Lichters et al., 2016b), I inspect how caffeine’s manipulation of cognition levels influences consumer decision-making. More precisely, I evaluated the stimulant’s impact on decision-making phenomena in product choice (i.e., context effects and choice deferral (Lichters et al., 2015)). I was able to observe a reduction in choice deferral rates for consumers of the psychostimulant while the magnitude of both the AE and the CE in free-choice and forced-choice decision situations on a between-subjects and within-subjects basis was enhanced. Furthermore, my findings directly contest previous arguments of the AE resulting from an intuitive decision-making process (Hedgcock, Rao, & Chen, 2009; Pocheptsova et al., 2009). The final chapter of my thesis closes by compiling all findings and providing a detailed overview of the implications which can be derived by my studies followed by an evaluation of their respective limitations. An insight on future research avenues completes my thesis.