Choosing Among Options Presented Sequentially or Simultaneously

Comparative Versus Holistic Processing

When people consider all options simultaneously compared with when they view them sequentially, they engage in different types of choice processes. Viewing options together nudges people to compare and contrast various attributes and features of the options, as well as to focus on ways in which the options differ from one another. The presentation format facilitates detailed comparative processing because all attributes of all options are simultaneously laid out in front of the decision maker. For example, people who viewed both common and unique symptoms of two diseases together were more likely to use the diagnostic-unique symptoms in a subsequent diagnosis task; in contrast, participants who viewed the symptoms of each disease sequentially paid less attention to the more relevant unique information (Klayman & Brown, 1993).

Viewing options sequentially, on the other hand, makes it difficult for people to engage in detailed comparative processing because only one option is in front of them at any given moment—the other options in the choice set are not immediately visible. Therefore, people need to evaluate each option on its own on the basis of all the information provided about that option and on the basis of any relevant information that they recruit from memory. They would then compare their overall evaluation of the option with either an internal reference point or their memory representations of previously encountered options. For instance, people who viewed hedonic consumer options (e.g., chocolate, wine) sequentially were less satisfied with their chosen option compared with those who viewed the same options simultaneously (Mogilner, Shiv, & Iyengar, 2013). In the sequential format, people considered each option against an imagined better option (i.e., an internal reference point) and hoped to encounter such a better option subsequently, which reduced their satisfaction with their chosen option.

The comparative processing engendered by simultaneous presentation and the holistic processing engendered by sequential presentation can influence people’s decisions in multiple ways, as we review below.

Consequences of Distinct Processing Styles

When people view options together, they are more likely to identify the objectively best option in a choice set because they engage in more in-depth cognitive processing than those who view options one at a time. In our research (Basu & Savani, 2017), participants chose options from choice sets containing four inferior options and one dominating option (e.g., a supplier providing the best rate for goods, a consumer product with the highest value on all attributes). Participants who viewed options together were more successful at identifying these dominating options than those who viewed the options one at a time. Moreover, this effect was attenuated when participants’ processing abilities were experimentally limited by a secondary task, which identifies the crucial role of cognitive processing.

A related stream of research on eyewitness identification provides converging findings (Gronlund, Wixted, & Mickes, 2014; Wixted & Mickes, 2014). The police can test eyewitness’ ability to recognize a suspect using either a simultaneous lineup (e.g., six people, including the suspect, presented side by side) or a sequential lineup (e.g., six people presented one at a time). Eyewitnesses are better able to distinguish among the candidates’ faces in a simultaneous lineup (Mundy, Honey, & Dwyer, 2007). Eyewitnesses make more accurate judgments in simultaneous lineups because this allows them to focus on distinctive, and therefore diagnostic, attributes of the candidates and also highlights that nonunique attributes are less helpful in making an accurate judgment (Wixted & Mickes, 2014).

Viewing options together may also lead people to make choices that are consistent with their preferences. In a study by Lévy-Garboua, Maafi, Masclet, and Terracol (2012), people were asked to choose one lottery from a pair of lotteries, with 10 such pairs presented either simultaneously or sequentially. Importantly, participants who viewed all pairs of lotteries together were more likely to exhibit consistent risk preferences (i.e., choosing all safe options above a certain risk threshold and all risky options below the threshold) than those who viewed each pair sequentially and were thus better able to express their risk preferences when making risky choices.

The greater comparative processing in the simultaneous format may lead people to focus on the differences between the options while disregarding common information, even if the common information is necessary for interpreting the differing information. In particular, numerical information consists of both a number and the unit or scale that is necessary for interpreting the number. When faced with options varying on a numerical scale, people often attend to the numbers while disregarding the scale, although the scale is essential for interpreting the numbers. For example, people judge the difference between 700 and 900 on a 1,000-point scale as larger than that between 7 and 9 on a 10-point scale (Pandelaere, Briers, & Lembregts, 2011). Recent research suggests that people are more likely to exhibit this bias when they view options simultaneously rather than sequentially (Schley, Lembregts, & Peters, 2017; see also Tao, Wyer, & Zheng, 2017), again indicating that simultaneous presentation shifts people’s attention away from common information (e.g., the unit or scale in this case).

The greater comparative processing elicited by the simultaneous format highlights trade-offs and thereby accentuates processes arising from trade-off salience. Participants in another study were presented with three options varying on two attributes (e.g., three hotels with ratings on accessibility and amenities) that were negatively correlated. When faced with difficult trade-offs, people tended to choose the compromise option (i.e., the hotel with the middle rating on accessibility and amenities; Simonson, 1989). This compromise effect was heightened when people viewed options simultaneously rather than sequentially (Jang & Yoon, 2016), probably because both the trade-off and the compromising nature of one of the options was more salient in simultaneous choice. Another manner in which people resolve difficult trade-offs is by deferring the choice, and indeed, people who viewed equally attractive options simultaneously were more likely to defer the choice than those who viewed the same options sequentially (Dhar, 1996).

When one views options sequentially, comparing each newly encountered option with previous options can highlight the unique aspects of the newly encountered option, thus leading to order effects in evaluation. Participants in a different study were shown three options of college dorm rooms one at a time; each option had unique positive features but shared negative features. When evaluating these options, participants focused only on the unique positive aspects of each newly encountered option but paid little attention to the common negative aspects (Bruine de Bruin & Keren, 2003). Similarly, analyses of the results of the Eurovision Song Contest and the World Figure Skating Contest revealed that judges’ evaluations of contestants increased linearly with the contestants’ order of appearance (Bruine de Bruin, 2005). In another study, when people were presented with equally appealing options, such as four chocolate cakes, they rated the options appearing later more positively (Bullard, Manchanda, & Sizykh, 2017). The order effects persisted both when participants rated each option as soon as they viewed it and when participants rated options after viewing all available options (Bruine de Bruin & Keren, 2003). When the options were presented together, such order effects were greatly reduced (Bruine de Bruin & Keren, 2003) or were completely eliminated (Bullard et al., 2017). Furthermore, the order effects were attenuated for participants who had a lower need for a reference point in the initial stage of the sequence (Bullard et al., 2017), providing further evidence for the underlying mechanism.

Future Directions

Future research can examine other downstream effects of these two option-presentation formats. For instance, when viewing options together, people might have a lot of information to process if there are many options varying on many attributes. To manage choice overload, people may use simplifying rules to help them reach a decision, such as counting the number of attributes on which one option is best and selecting the option with the majority of winning attributes (majority rule; Russo & Dosher, 1983) or breaking down a choice with a large number of simultaneously presented options (e.g., choosing 1 of 24 different sandwiches) into a sequence of simpler choices (e.g., choosing the bread, choosing the filling, choosing the sauce) that are more tractable, thereby converting one large, unmanageable, simultaneous choice into a sequence of smaller simultaneous choices (Dorn, Messner, & Wänke, 2016). On the other hand, when viewing options one at a time, as people have difficulty comparing across options, they might focus more on comparing options with an internal reference point. Therefore, they may evaluate each attribute of each option against an internal reference cutoff point and select the option that has the maximum number of attributes fulfilling the decision maker’s reference point (Alba & Marmorstein, 1987). Furthermore, the decision strategies and option-presentation format may sometimes interact. For instance, when people encounter options that have a large number of attributes, comparing options on attribute information may be tedious, even when options are viewed together. In such cases, even in simultaneous format, people may resort to a holistic, alternative-based processing strategy.

The general difference between more comparative and more holistic processing in simultaneous- and sequential-presentation formats, respectively, can take a number of different specific forms, especially when people are making multiattribute choices. For example, people might be more likely to use by-attribute comparisons when viewing options simultaneously and by-alternative comparisons when viewing options sequentially (Bettman, Luce, & Payne, 1998). When viewing options simultaneously, people might be more likely to use the elimination-by-aspects strategy (i.e., eliminating options failing to meet the cutoff value for an important attribute; Tversky, 1972). When viewing options sequentially, people might be more likely to use a weighted-additive strategy (Payne, Bettman, & Johnson, 1988) whereby they multiply each value of each attribute with its subjective importance in the decision and compare the resulting value across options. Future research can test whether sequential or simultaneous option presentation alters the specific decision strategies that people use when making multiattribute choices.

In nearly all the above-cited research, people had to choose among options belonging to the same category (e.g., five different lotteries, five different laptops). However, oftentimes, people might be choosing among options belonging to different categories (e.g., whether to go on a vacation or to renovate one’s house) that cannot be compared along a parallel set of attributes (Cho, Khan, & Dhar, 2013). Given that simultaneous presentation encourages people to compare attributes across options, encountering noncomparable attributes may reduce their ability to make a decision and their satisfaction with the decision that they ultimately make. In contrast, if people evaluate each option on its own and compare their holistic evaluation of the different options, they might be quicker to make a decision and be more satisfied with their decision. Even when the options belong to the same category, sometimes attribute values of one or more options may be missing (e.g., no information from Consumer Reports about a new refrigerator), which can lead people to defer making a choice (Gunasti & Ross, 2008). When people view options one at a time, the absence of full attribute information may become less salient, thus reducing uncertainty and helping people make a choice. Future research can test these possibilities.

Future research can also examine whether specific procedural design choices used in past research might systematically influence people’s decisions. For example, in some studies using the sequential format, people could go back and forth among all of the options (e.g., Basu & Savani, 2017), whereas in others they could not (e.g., Bruine de Bruin, 2005). It is possible that some of the biases arising in the sequential presentation might be attenuated if people could go back to previous options and thereby do more detailed comparative processing than would otherwise be possible. Nevertheless, differences between the simultaneous and sequential formats were observed even when people could go back and forth among the options in the sequential format (Basu & Savani, 2017).

Finally, we have been assuming that when presented with multiple options simultaneously, people would tend to compare specific attributes of the options with each other. However, this need not always be the case. For example, recruiters faced with a large number of applicants’ curricula vitae (CVs) might still process each CV one at a time, even with all the CVs laid out in front of them. Future research can examine the conditions under which people spontaneously adopt holistic processing even when all options are simultaneously available.

Viewing options one at a time or all together is one of the most fundamental decisions people make before embarking on a choice task. It is also a choice-architecture tool for managers and policy makers. Our article sheds light on this nascent but important area of research and deepens our understanding of the way option presentation affects decisions.

Recommended Reading

Basu, S., & Savani, K.(2017). (See References). A series of studies examining the underlying reason for the positive effect of viewing options together on decision quality.

Bruine de Bruin, W., & Keren, G. (2003). (See References). A series of studies examining the mechanism underlying order effects.

Mogilner, C., Shiv, B., & Iyengar, S. S. (2013). (See References). A series of studies examining the role of emotions on the positive effect of viewing hedonic options together.

Wixted, J. T., & Mickes, L. (2014). (See References). A review of the impact of sequential and simultaneous lineups in eyewitness-identification research.