본 논문에서는 상점을 사용하여 선택 대안들을 묶는 Kahn et al.(1987)과 같은 방식으로 외부제약을 핵심 선택집합에 추가되는 대안과 함께 부과했을 때 유인효과와 타협효과에 미치는 영향의 차별성을 살펴보았다. 즉 표적대안과 경쟁대안으로 구성된 핵심 집합에 표적대안과 가까이 위치한 비대칭적으로 지배된 대안(표적대안에 의해서는지배되지만 경쟁대안에 의해서는 지배되지 않는 미끼대안)이 표적대안과 함께 쌍으로 묶이는 외부제약과 함께 도입되면 유인효과가 사라질 수 있는지(가설 1), 반면에 표적대안과 가까이 위치한 극단적 대안이 표적대안과 함께 쌍으로 묶이는 외부제약과 함께 도입되어도 타협효과가 발생하는지를(가설 2) 조사하였다. 두 차례의 실험 결과, 본연구에서 제시한 가설들은 전반적으로 지지되었다. 구체적으로, 비대칭적으로 지배된 대안이 표적대안과 함께 쌍으로 묶이는 외부제약과 함께 도입되면 외부제약이 부과되지 않은 조건에서와는 달리 유인효과는 발생하지 않은데 반해서(실험 1의 결과), 극단적 대안이 표적대안과 함께 쌍으로 묶이는 외부제약과 함께 도입되면 외부제약이 부과되지 않은 조건에서와 마찬가지로 타협효과는 발생하는 것으로 나타났다(실험 2의 결과). 본 연구 결과의 이론적 시사점과 마케팅 전략적 시사점을 제시하였고, 마지막으로 본 연구의 한계와 미래의 연구방향에 대해서도 논의하였다.
Context effects have been of interest to consumer behavior researchers for the past several decades. Extant research examined how individuals are susceptible to seemingly small (and often rationally irrelevant) factors in the decision environment. Two of the most important and robust context effects are the attraction effect (or asymmetric dominance) and the compromise effect. The attraction effect refers to the phenomenon whereby an asymmetrically dominated alternative, when added to a set, increases the attractiveness and choice probability of the dominating alternative (Huber, Payne, and Puto 1982). On the other hand, the compromise effect occurs when the choice probability of an alternative increases when it is the middle option, compared to being an extreme option (Simonson 1989).
There has been a substantial amount of research related to the issues of constrained choice (e.g., Kahn, Moore, and Glazer 1987; Tversky and Sattath 1979). On the basis of predictions from their model (PRETREE), Tversky and Sattath (1979) suggested that an external constraint that is consistent with the natural structure of the choice set would not affect choice probabilities. For example, an external constraint that forces similar items to be paired together would not affect the overall choice process because the imposed extrinsic structuring would be consistent with the natural structuring of the choice set. Kahn et al.
(1987; see also Glazer, Kahn, and Moore 1991) also tested the empirical validity of the prediction that external constraints that are consistent with a choice set’s natural structure do not affect choice. Kahn et al. (1987) and Glazer et al. (1991) studied decision problems in which participants chose between two stores. In each problem, one store offered a single item while the other store offered a pair of items. For example, in Kahn et al.’s (1987)experimental studies, participants were asked to assume that they could buy a soft drink in either of the two stores located equidistant from them; one store offered a single item (e.g.,Coke) while the other store offered a pair of items (e.g., Diet Coke and 7-Up). Then, the participants were asked to imagine that they intended to buy a single item and to indicate at which of the two stores they preferred to make their purchases. In a control condition, no mention was made of any stores and none of the items was singled out from the others;participants were simply asked which of the three items was their favorite. The findings revealed a systematic bias toward choosing the group: participants selected the store offering the group of items more often than they selected those items in the control condition.
Therefore, in contrast to PRETREE predictions, Kahn et al. (1987) and Glazer et al. (1991)found that external constraints affect choice even if they are consistent with the choice set's natural structure; that is, the dissimilar alternatives had significantly lower choice probability when it was the lone alternative pitted against the other pair of similar alternatives than it did in the unconstrained situation (i.e., a significant lone-alternative effect occurred).
As stated before, although there has been a substantial amount of research relevant to the issues of constrained choice (e.g., Kahn et al. 1987; Tversky and Sattath 1979), little is known about the dynamics of choice among options with the natural structure of the category (Ha, Park, and Ahn 2009). Addressing this void, Ha et al. (2009) suggested that analyzing differences in the processing of choices with and without external constraints can be a promising initial step toward understanding the dynamics of choices that involve natural categories. A categorical attribute, when it is important and diagnostic, often creates an agenda or a constraint on an offered choice set, facilitating category-based choice processes (e.g., Tversky and Sattath 1979). Adding to our understanding of choice context effects by reemphasizing the importance of categorical information in choice, Ha et al. (2009) examined the impact of categorical attributes on choice context effects and proposed that the introduction of an important/salient categorical attribute in the choice set tends to have a differential impact depending on the relative position of the third option. Specifically, Ha et al. (2009)demonstrated that the asymmetric dominance effect is attenuated by the introduction of an important/salient categorical feature (e.g., vacation tour site for vacation packages) in the competing option, while the tendency to prefer a middle option is not significantly affected.
Building on these previous findings, therefore, the current research examines how the externally imposed constraints forcing similar options to be grouped together influence the choice context effects such as the attraction and compromise effects which occur when the third option (e.g., the asymmetrically dominated or the extreme option) is added to the binary core choice set comprising of two options (i.e., the target and the competitor). External constraints forcing some options to be grouped together were imposed by using a relatively unimportant/nonsalient attribute which does not play a significant role in consumer choice setting. Specifically, we propose that the attraction effect (i.e., adding an asymmetrically dominated option to a binary core set can increase the choice probability of the asymmetrically dominating option) does not occur when the external constraints are imposed on the threeoption extended set (hypothesis 1). Also, we propose that the compromise effect can occur by adding an extreme option to the binary core set even when the external constraints are imposed on the three-option extended set (hypothesis 2). Two experiments tested these two hypotheses. We selected vacation tour packages as the target categories and used France as a vacation site for all of the tour package options. Three nontrivial attributes were chosen for vacation tour packages: travel agencies selling France packages, hotel service quality,and hotel location. In particular, following the methodology of Kahn et al.'s (1987) studies,we introduced the choice environments with externally imposed constraints by framing the experimental setting in terms of a choice between travel agencies which do not play a significant role in choosing tour packages. The dependent variable was option choice. All of the tour package options were described in an attribute by alternative matrix format, and the positions of the choice options were counterbalanced across participants. Each participant took part in two sessions separated by a 1-week period. In the first session, participants were asked to choose from the two-option core set. One week later, participants were asked to choose again from the three-option extended set. As a result, hypothesis 1 was supported,and hypothesis 2 was marginally supported. Finally, we discuss the theoretical and practical implications of our findings and develop directions for future research.