Full length articleThe Experimental Tobacco Marketplace II: Substitutability and sex effects in dual electronic cigarette and conventional cigarette users
Introduction
We are in a moment of profound change with the advent of numerous novel tobacco products and a high incidence of morbidity and mortality related to smoking (Jamal et al., 2015, United States Department of Health and Human Services, 2014, World Health Organization, 2011). The behavioral economic assessment of elasticity of demand (i.e., sensitivity to price) and the interaction of commodities as either substitutes, complements, or independents have provided an important framework representing the factors that govern tobacco consumption (Bickel et al., 1995). To explore those factors, we created the Experimental Tobacco Marketplace (ETM), an online store in which the researchers can manipulate price, product availability, and other variables of interest, in an experimental forum resembling the real-world marketplace (Epstein et al., 2012, Epstein et al., 2010, Quisenberry et al., 2015).
A fundamental observation of behavioral economics is that the type and number of products in a marketplace can alter demand elasticity and the type and degree of interaction among products (Johnson et al., 2004, Quisenberry et al., 2015). As a result, the ability to achieve the tobacco control goals of reducing product consumption may be informed via the economic processes of substitution and complementarity (Bickel et al., 1995). Substitution defines one end of a continuum representing interactions between two commodities and is described as an increase in the consumption of a fixed-priced product (e.g., Coca-Cola®) while the cost of another commodity (e.g., Pepsi Cola®) is increased. At the other end, commodities function as complements, which refers to the decreased consumption of a fixed-priced product (e.g., soup crackers) in response to an increase in the price of another commodity (e.g., soup). Between these two extremes is independence, which occurs when changes in the price of one commodity (e.g., Coca-Cola®) have little or no effect on consumption of a fixed-priced commodity (e.g., soup crackers). Substitution, complementarity, and independence are measured by cross-price elasticity of demand.
Manipulating price to assess cross-price elasticity of demand using an alternate behavioral economic method of self-administration (Bickel et al., 1995, Johnson et al., 2004) is achieved by increasing the response cost required (i.e., number of plunger pulls). Using this method, Nicorette gum has been shown to function as a substitute (Shahan et al., 2000) when concurrently available with increasing price of cigarettes. An additional study that varied product availability revealed that Nicorette gum and denicotinized cigarettes functioned as a substitutes when each was available independently, but when both were available concurrently denicotinized cigarettes were a greater substitute than Nicorette gum (Johnson et al., 2004).
Product availability has also been shown to influence level of substitution using the ETM methodology (Quisenberry et al., 2015). A two-experiment study where the price of conventional cigarettes was manipulated found differences in the substitution profiles of alternative products when cigarillos were or were not available. In the presence of cigarillos, e-cigarettes and cigarillos were substitutes. However, when cigarillos were removed from the ETM, both e-cigarettes and Camel Snus® functioned as substitutes.
Just as important as the products available are the characteristics of the consumer. For example, e-cigarette substitution of factory made and roll your own cigarettes in New Zealand smokers differed such that consumers of roll your own cigarettes purchased more e-cigarettes than consumers of factory made cigarettes (Grace et al., 2015). With the popularity of e-cigarettes increasing, exploring substitution among different dual users is necessary.
Sex is another important consumer characteristic that influences consumption. Indeed, noticeable sex differences exist in tobacco product use. For example, 9% of females globally smoke cigarettes versus 40% of men (WHO, 2010). Among alternative tobacco products, sex differences exist such that Camel Snus® is more likely to be sampled by males in North America (Biener et al., 2014, Biener and Bogen, 2009) and Sweden (Norberg et al., 2011). In addition, evaluation of the reinforcing efficacy (i.e., the relative ability to maintain or change behavior) of Snus in a self-administration paradigm concluded that Snus administration was associated with decreased latency to smoke cigarettes in males, but not females (Barrett et al., 2011). Similarly, in a naturalistic demand assessment study, males were more likely to purchase Snus than females (Bickel et al., 2017; Stein et al., 2016).
The aim of the current study was to evaluate the reinforcing efficacy of conventional cigarettes and alternative tobacco products using the behavioral economic ETM. To this end, male and female dual conventional cigarette and e-cigarette users were exposed to the ETM and purchased products for potentially real use over the next week. We hypothesized that: (1) e-cigarettes would function as a strong substitute at high cigarette prices and (2) males would purchase Snus at a higher rate than females.
Section snippets
Participants
Participants were recruited in the Roanoke, VA community via referrals, fliers, and Internet advertisements (i.e., Facebook and Craigslist) seeking electronic cigarette and cigarette smokers for research involving tobacco product purchasing and questionnaire completion. To participate in the study, participants must have met DSM IV (American Psychiatric Association, 2000) criteria for nicotine dependence, reported smoking between 10 and 40 cigarettes per day, smoked an e-cigarette in the last 30
Results
Account balances (M = 39.21, SD = 17.01) provided to each participant based upon their weekly tobacco use were not statistically different between males (M = 37.20, SD = 20.37) and females (M = 41.04, SD = 14.25) [t (19) = .504, p = .959]. Likewise, the remaining account balance in the actualized condition (M = 12.07, SD = 11.83) was not different between females (M = 13.86, SD = 13.14) and males (M = 10.11, SD = 10.54) [t (19) = .72, p = .336]. Model fit and demand parameters for the total sample, males, and females are
Discussion
The current investigation of reinforcer valuation (i.e., the value placed on a reinforcer) using the ETM found that in dual e-cigarette and conventional cigarette users, own-price elasticity of cigarettes decreases as price increases, replicating a common result (Johnson et al., 2004, Quisenberry et al., 2015, Shahan et al., 2000) in a different population. Evaluation of cross-price elasticity revealed high rates of e-cigarette purchasing across all cigarette prices, with substitution occurring
Conclusions
In conclusion, any intervention focused on altering consumption should consider target characteristics informed by research such as the current article. The ETM provides an experimental forum that resembles real-world purchasing in which to evaluate the interaction among consumption of cigarettes, consumption of alternative tobacco products, and consumer characteristics.
Role of funding source
This project was financially supported by a subcontract for a grant from International Tobacco Control research programs project P01CA138389.
Conflict of interest
No conflicts of interest declared by any author.
Contributors
All authors have contributed to the development of the project and manuscript. All authors have also read and approved the final manuscript. WKB and LHE contributed to the development of the experimental design. MNK assisted with analyses and interpretation. AJQ implemented the experimental design and prepared the manuscript.
Acknowledgements
We would like to thank the members of the Addiction Recovery Research Center team for their help collecting the data presented in the manuscript.
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