This research examined the role of values and value-tailored messages in emotional responses to wastewater products. Given the possible implications of wastewater products for both the environment and one’s personal comfort, we focused on the role of biospheric and hedonic values that reflect a concern with the environment and personal comfort, respectively. We predicted that individuals with stronger biospheric values would report more positive and less negative emotions in response to wastewater products, whereas individuals with stronger hedonic values would report less positive and more negative emotions. Additionally, we predicted that the relationships with positive emotions would depend on value-tailoring, that is, presenting the products as having positive implications for the relevant values. We hypothesised that value-tailored messages would increase positive emotions towards the products. We also examined whether emotions, in turn, were associated with acceptability of wastewater products and intentions to purchase wastewater products. Overall, the hypotheses were partially supported. We provide further explanation of the results separately for biospheric and hedonic values below.
Biospheric values and emotions towards wastewater products
Biospheric values were associated with more positive emotions towards the products (i.e. supporting H1). Importantly, as expected, we found that this relationship was stronger when the product messages emphasised the positive environmental consequences of wastewater products (i.e. the positive implications for biospheric values; supporting H5). Thus, it appears that, in general, the stronger their biospheric values, the more positive emotions people have towards wastewater products, and this is even more likely when the benefits for the environment are emphasised in the product messages.
Interestingly, we did not find a significant relationship between biospheric values and less negative emotions towards wastewater products (not supporting H2). This could have been because our selected products did not elicit very strong negative emotions in the first place. Specifically, the low mean scores and low variance for the measures of negative emotions suggest that the specific products that we included may have not been ‘disgusting’ enough to generate sufficient variation in the negative emotion responses, or that the emotion terms selected to represent negative emotions were too strong for the products. For instance, 89% of participants chose “Not at all” when asked if they feel uncomfortable when imagining using the table top. Thus, the specific products chosen for the current research seem to have produced a floor effect for the measure of negative emotions. Previous research has found that people can be distressed about [39], and unwilling to consume [30] treated wastewater. However, the wastewater products included in the current research may not have been considered as disgusting as recycled water, because these products do not have to be ingested or come into contact with the body (see also, [13, 20]). Therefore, we would recommend that a wider range of products are included in future studies, particularly products that involve a high degree of physical contact or are used for oral consumption (e.g., drinking cups or straws).
Hedonic values and emotions towards wastewater products
Hedonic values were weakly associated with negative emotions towards the plant pot, but not the table top (i.e. partially supporting H3). Hedonic values were also significantly associated with positive emotions (not supporting H4), especially when the product messages emphasised the pleasurable benefits of the products (i.e. the positive implications for hedonic values). Contrary to what we predicted in H6, however, this relationship seemed to be driven by weaker hedonic values. Specifically, weaker hedonic values were associated with less positive emotions when the pleasurable benefits were emphasised, relative to when the environmental benefits were emphasised, whereas stronger hedonic values were associated with similar levels of positive emotions in both message frames.
The relatively weak relationships between hedonic values and emotional responses towards wastewater products suggest that these kinds of products—or, at least, the products included in the current research—are probably not perceived as having major implications for hedonic values. This is unlikely to be due to different overall levels of endorsement of hedonic values in the sample, since both hedonic and biospheric values were endorsed by participants to a similar degree. The explanation that the current products did not have strong implications for hedonic values is also plausible because we found very low scores on negative emotions—which suggests that most people did not feel disgusted, anxious or uncomfortable in response to the products. Future research could include more disgusting products.
Another potential reason why hedonic values did not strongly predict emotions, is that the hedonic message frame may not have been relevant enough in this context. That is, the hedonic frames may have been generally less appealing than biospheric frames. For example, it could be the case that messages emphasising the environmentally friendliness of wastewater products are simply more convincing and intuitive (because this would be a primary reason to use such materials), whereas messages emphasising their pleasurable qualities may be seen as confusing, or even disingenuous (since these products might not be experienced as typically pleasurable in nature). Additionally, emphasising the origins of the materials could have had an unexpected effect of making the products seem more special and unique (given that products made from recycled toilet paper are relatively uncommon), whereas emphasising the pleasurable aspects of the products could have unexpectedly made the products seem more generic and conventional (i.e. just describing a product as ‘unique’ does not necessarily make it actually appear unique, because this is a very common marketing strategy). Alternatively, perhaps the hedonic frame may have immediately led people to consider the potential negative hedonic aspects of the products as well—although this explanation would still imply that stronger hedonic values would tend to have less positive emotions towards the products, which was not supported.
Unexpectedly, it appeared that individuals with weaker hedonic values, tended to express less positive emotions to the products when the hedonic frame was employed, relative to the biospheric frame, whereas individuals with stronger hedonic values did not differentiate strongly between the frames in their emotional responses. This suggests that when message frames are used that try to appeal to values that people find less important, these frames could potentially backfire. Future research should try to replicate and clarify the reasons for this finding. One possible explanation is that the hedonic message frame contained content less relevant to hedonic values (e.g., “drawing attention” could communicate a status motivation, which is more relevant for egoistic values). Additionally, while the biospheric frame primarily communicated implications for one main value, the hedonic message may have contained mixed content relevant to both hedonic and biospheric values. For example, even just stating that the products are made from biodegradable plastic and reused toilet paper could imply that they are good for the environment, in addition to the hedonic content implying that they are also good for the self, which may have reduced the clarity of the hedonic message. Some previous research has found that combined messages (e.g., incorporating both biospheric and egoistic frames; van den [37] are less effective than single-value appeals, showing that messages tailored towards a specific value can be more effective than messages that attempt to appeal to multiple values. Future research could also further investigate the effectiveness of combined product messages incorporating both hedonic and biospheric content.
In the current research, we did not see negative effects of the biospheric frame for individuals with strong hedonic values. This may indicate that people can believe that products can be both sustainable and pleasurable, and there is not necessarily a trade-off between hedonic values and pro-environmental behaviours (e.g., [38]. Yet, overall, the hedonic messages in the current research seemed to be less effective for eliciting positive responses to wastewater products than the biospheric messages.
The current findings make a unique contribution by being one of the first studies to investigate the role of hedonic values and hedonic messages in the context of consumer products that are likely to have negative implications for hedonic values, and elicit negative emotions. Most past research on value-congruent messaging and pro-environmental behaviours has not explicitly focused on hedonic values and messages, focusing instead on messages tailored towards either biospheric or egoistic values (e.g., [21],Van den [37], or not distinguishing hedonic messages from egoistic messages within a broader “self-enhancement” message frame (e.g., [4, 12]). For example, Herziger et al. [12] describe “wellbeing enhancement and stress reduction” as “selfish” interests related to egoistic values, although, arguably, these messages could also communicate self-care, which may be more relevant to hedonic values. Similarly, in the research by de Dominicis et al. [4], some of the content of the “self-enhancement” message frames appeared to be more hedonic in nature, such as people having fun at the beach. It can be quite difficult to disentangle egoistic and hedonic content when constructing messages that target solely one of these values. Indeed, even the hedonic frame in the current study could be viewed as containing egoistic elements (e.g., the reference to “drawing attention” could communicate a concern for one’s status). Thus, future research could pilot-test the specific value-tailored messages, to ensure that they are communicating the primarily targeted value. Hedonic values and hedonic message frames may have different effects on emotions towards sustainable products than egoistic values and egoistic message frames, for one because people may not perceive caring about the environmental benefits and the personal pleasure derived from such products as mutually exclusive, while they might do so for behaviours that are good for the environment and good for saving money. It appears that more research is needed to study the unique effects of hedonic values and hedonic message frames in the value-tailoring literature.
Emotions, acceptability and intentions to purchase
We found consistent support for H7; positive emotions were associated with higher acceptability of wastewater products, and higher intentions to purchase wastewater products, whereas negative emotions were associated with lower acceptability of wastewater products, and lower intentions to purchase wastewater products. Emotions have been found to be highly intertwined with acceptability and are thus a relevant component in people’s reactions. In this paper, we have chosen to focus on investigating emotions, in particular, because these types of products could presumably cause strong emotions (e.g., disgust). H7 predicted that emotions would be associated with intentions to purchase; however, we did not hypothesise that emotions would act as a mediator, as this would suggest that emotions come first in a causal chain, before intentions. This causal chain may not necessarily be the case (e.g., [22, 31], and our design does not allow us to test causality or what comes first—emotions or intentions (rather, it is focused on testing the casual effects of value framing on emotions). Thus, we have focused on reporting the associations between emotions, acceptability and intentions. While we have run some exploratory moderated mediation analyses (see the Additional file 1), more experimental studies are needed to directly test the effects of emotions on intentions to purchase products.
The current findings are broadly consistent with previous research on the effects of message framing in responses to environmentally friendly products (e.g., [8, 15, 30]). Overall, our findings provide support that the implications of sustainable innovations for one’s strongly held values play a role in the elicitation of emotions and the acceptance of these innovations [24]. The findings are also consistent with previous research that has demonstrated that message framing can shape emotional reactions to wastewater products, like recycled water (e.g., [10]. We have extended this literature by demonstrating the key role of values in emotional responses to wastewater products.
Limitations and future research
It is important to note that the current findings are based on a single study, and more research is needed to replicate and support these findings. A further limitation to this study is that we were not able to demonstrate whether the hedonic and biospheric message frames had beneficial effects when compared to a control condition (e.g., a condition containing very basic information about the product, with little value-related content). A control condition would allow for testing which of the message frames was primarily driving the effects on emotions (or if both messages were having an effect). We therefore recommend that future research includes a control condition. Another limitation is that we did not measure the perceived implications of the products for participant’s values. Thus, it cannot be concluded with certainty that people with stronger biospheric values had more positive emotions towards wastewater products because they perceived these products to have positive implications for their biospheric values (although the findings strongly suggest this). Future research could also include a measure of perceived value-congruence; that is, the extent to which participants think that a product has positive implications for their core values. Additionally, we were not able to conclude that the “hedonic” message frame was perceived as especially relevant to hedonic values. Future research could further test the effects of framing, particularly the hedonic framing; for example, by including clear value-relevant frames that have been pilot-tested. Alternative outcome measures also could be included in future research, such as relative willingness to pay (e.g., [29]), or behavioural measures; for example, by giving participants the opportunity to actually buy wastewater products. This would provide more evidence for the ecological validity of the findings and show that the manipulations are likely to have an impact on real-world behaviours.
Broader avenues for future research could include examining the role of other values, such as egoistic values or conservation values (i.e. valuing order and preserving the status quo; [33]). Previous research has found that purity and conservation values tend to be linked to trait disgust sensitivity (e.g., [14]; but see [5]), for a recent critique of this perspective). Therefore, it may be the case that ‘disgusting’ wastewater products evoke more negative emotions for people who hold strong conservation values than people who hold strong hedonic values.
Future research could also consider a more longitudinal perspective, rather than measuring reactions at a single time point. For example, disgust responses can change within individuals over time, a shift that can be intentional (e.g., via the motivated up-regulation or down-regulation of disgust to behave in ways that are more consistent with one’s values) or unintentional (e.g., from repeated exposure). For instance, there is recent evidence that people who work with meat (e.g., butchers, deli workers) exhibit adaptation of their disgust responses to meat over time [28]. In the current context, it is possible that individuals with stronger biospheric values may be motivated to down-regulate their disgust responses to wastewater products over time, because these products fit with their values. Also, arguably, the meaning of what is considered “disgusting” in society has changed a great deal over the course of history, and many culturally accepted innovations (e.g., fermented foods) could also be considered disgusting from a different cultural perspective [16]. Thus, disgust responses to circular economy products may be more amenable to change than is commonly assumed, and more research is needed in this area.
Practical implications
The current findings provide useful insights for how to promote wide adoption of wastewater products. Although stronger biospheric values can lead to positive emotional reactions towards wastewater products, it may be important to clearly explicate the implications of the products for these values to consumers, in order to maximise the positive effect (consistent with the literature on value activation; e.g., [35]. Companies who are developing wastewater products may be reluctant to promote these products as environmentally friendly, since they may be concerned that this would increase the salience of the product’s origins and deter consumers from purchasing their products, particularly those with stronger hedonic values. The current findings suggest that this is not a major concern, participants holding strong hedonic values did not seem to have strong negative emotional responses to this type of wastewater product, even when the environmental benefits were emphasised. Thus, people do not seem to have large concerns about the implications of these products for their hedonic values. The findings also suggest that wastewater products are mostly appreciated for their environmentally friendly characteristics; in general, biospheric framing led to more positive emotions towards these products than hedonic framing, and there were more positive emotions elicited when the audience held strong biospheric values. Therefore, when audiences hold a variety of different values, it would likely be most beneficial to use biospheric message frames emphasising the positive benefits of the products for the environment. However, we should caution that we only included a small number of products and two types of values in the current research, and the hedonic frame did not produce the outcomes that we had expected. More research is needed to find out whether the findings would extend to other products, particularly products that require more physical contact, or how individuals respond based on their egoistic or altruistic values. Additionally, although the current research shows that biospheric frames can elicit positive emotions in people with strong biospheric values, it is less clear how we motivate people with low biospheric values to adopt wastewater products. This is another area for future research.