The relationship between determinants of husband–wife agreement and household climate change mitigation behavior

Reducing carbon emissions from household activities is an important element in achieving climate goals. Engagement in household climate change mitigation behaviors usually requires interaction and negotiation among household members. Congruence theory suggests that individual-determinants of climate change mitigation behavior are strongly influenced by household-level determinants, such as mutual agreement between couples, but few studies have empirically tested this hypothesis. Being a pioneer study of its kind in the field of climate change mitigation behavior, a unique dataset that contained the survey results of 152 married heterosexual couples in Taipei City, Taiwan was used to test the congruence effect on household climate change mitigation behaviors. Eight theoretical determinants of household climate change mitigation behaviors (five at individual-level and three at household-level) and the level of engagement in three household climate change mitigation behaviors were analyzed. Results from a response surface analysis suggested that none of the five individual-level determinants exhibited congruence effects, while two out of three household-level determinants exerted congruence effects on the behavior of energy-efficient appliance purchasing. In other words, based on the results of this study, married heterosexual couples having similar attitudes regarding household-level variables but not individual-level variables is a nonnegligible factor influencing engagement in household climate change mitigation behaviors that require a certain level of intrahousehold interactions.


Introduction
With climate change posing an increasingly serious threat worldwide, the roles of individual or household climate change-related behaviors are becoming crucial (Skeirytė et al 2022, Bergquist et al 2023).Studies on this topic suggested that many factors are likely to influence climate change mitigation behaviors, such as positive and negative spillover (Lacroix et al 2022), work-life preferences (Chapman et al 2023), levying environmental taxes (Karmaker et al 2021) and moral licensing (Burger et al 2022).Scholars have also noticed that people are more inclined to participate in behaviors that have low emission reduction potential than high emission reduction potential (Lacroix 2018).In addition, many studies treat climate change mitigation behaviors, such as turning off lights when leaving rooms or purchasing energy-efficient household appliances, and adaptation behaviors, such as household hurricane preparedness behaviors, as individual-level behaviors.However, studies have suggested that these should be considered household-level behaviors (Seebauer et al 2017, Hung 2018) and that intrahousehold dynamics are key in the engagement of household climate change-related behaviors (Hung and Wang 2022a).One intrahousehold factor proposed to influence household climate change-related behaviors is the agreement of household members on climate change-related topics (Paton 2015).A handful of studies, most of which are qualitative, have demonstrated that when members of a household disagree on matters pertaining to climate change (Proudley 2008, Whittaker et al 2016, Tyler and Fairbrother 2018, Al-Amin et al 2019), they are less likely to engage in climate change-related behaviors (Villarreal and Meyer 2020) and vice versa (Hung 2019).However, because research on this topic is limited, whether agreement of climate change-related predictors is related to household climate change-related behaviors requires further examination, especially quantitatively.Agreement is an established subject in marketing and social psychology research, and studies have used polynomial regression with response surface analysis to overcome methodological problems and provide more valid results on the relationships between agreement and outcome variables (Shanock et al 2010, Barranti et al 2017, Tsai et al 2022).
With a unique dataset collected from married heterosexual couples in Taipei City, Taiwan, this study used polynomial regression with response surface analysis to investigate whether husband-wife agreement in the level of predictors of climate change mitigation behaviors in households is associated with household climate change mitigation behaviors.To the best of our knowledge, this is the first study to explore this topic using novel statistical methods (i.e., polynomial regression with response surface analysis) to investigate the effects of interfamily-member agreement (i.e., congruence) on household climate change mitigation or adaptation behaviors.As this study is one of the pioneer studies to investigate the abovementioned topic, this study adopts an inductive, exploratory approach to conduct the study, aiming at creating a crucial reference for future theoretical development of this research topic.
2. Literature review 2.1.Factors that influence climate change mitigation behaviors Household activities are associated with considerable greenhouse gas emissions (Wang et al 2021), and understanding factors that influence mitigation behaviors is crucial to achieving climate goals (Lacroix 2018).Climate change risk perception is a crucial predictor of mitigation behavior (Brody et al 2012) because individuals are more likely to engage in mitigation behaviors when they perceive risk associated with climate change (Brügger et al 2015).Individuals with stronger proenvironmental attitudes exhibit greater motivation to mitigate climate change (O'connor et al 1999(O'connor et al , Whitmarsh 2009).In addition, if an individual perceives that the responsibility for taking mitigation actions lies with other entities like governments or companies, they are unlikely to engage in these actions themselves (Bichard and Kazmierczak 2012).Furthermore, Brody et al (2012) demonstrated that self-efficacy, the perceived ability to perform mitigation behaviors, is positively correlated with motivation for behavioral change to mitigate climate change.Finally, motivation, usually considered to be antecedent to behavior, is significantly related to engagement in mitigation behaviors (Hung and Bayrak 2019).
In addition to aforementioned factors used in individual-level analysis, because household-level behaviors are determined by communication and negotiation among household members (Grønhøj 2006, Thøgersen andGrønhøj 2010), factors salient in these interactions must be considered.First, gender norms are crucial in household decision-making not only because the division of household labor is determined by the interactions of gender norms held by household members (Greenstein 1996, Coltrane 2000), but also because gender norms can result in gendered climate change related behaviors through the division of household labor (Druckman et al 2012; Hung and Wang 2022a).Furthermore, when individuals believe that engagement in mitigation actions is difficult for their family, they are less likely to perform household mitigation actions (Heath and Gifford 2002).Finally, perceived conflict when undertaking mitigation actions must be considered because when respondents believe that discussing mitigation actions will cause conflict among household members, they perceive raising the topic for discussion as difficult, making the creation of an environment conducive to mitigation action unlikely (Binder et al 2011).

Agreement among household members and climate change mitigation behaviors
Studies have demonstrated that treating climate change mitigation and adaptation behaviors as individual-level behaviors ignores the importance of intrahousehold dynamics and interactions in climate change mitigation and adaptation behaviors (Seebauer et al 2017, Hung 2018).Drawing on findings in related fields such as research on sustainable households, proenvironmental behaviors, and household decision-making, Hung and Wang (2022a) suggested that seven intrahousehold factors are likely to influence household climate change adaptation processes-gendered division of labor, disagreements, conflicts and conflict resolution strategies, decision-making stages, decision-making types, interpersonal influence, and household life cycle-and three factors are likely to influence adaptation outcomes-gendered adaptation behaviors, relational behaviors, and household life cycle and adaptation behaviors.
Disagreement is an intrahousehold factor discussed by Hung and Wang (2022a), and research has explored areas such as whether household members have similar perceptions regarding climate change-related issues and whether agreement reached by household members is significantly related to desired outcomes.Household members sometimes disagree regarding climate change adaptation behaviors such as wildfire evacuation plans (Tyler and Fairbrother 2018), and husbands and wives may have different climate change risk perceptions (Al-Amin et al 2019).These types of disagreement among household members may have negative impacts, such as delayed decisions or intrahousehold conflict (Tyler andFairbrother 2018, Villarreal andMeyer 2020).
Another study by Hung (2019) utilized categorical variables to indicate whether husbands and wives agreed as to who shoulders the responsibility for hurricane preparedness behaviors and used chi-square tests to investigate the relationship between agreement and household hurricane preparedness.This study demonstrated that husband-wife agreement was significantly associated with planning-related preparedness behaviors.However, because the results were based on categorical data, they may differ from those of studies that analyze Likert-scale measurements, suggesting that more studies are necessary to validate the relationship between agreement and desirable outcomes.

Congruence theory and response surface analysis
Agreement is a popular subject in marketing and social psychology (Kenny et al 2006, Shanock et al 2010).Congruence theory, from psychology, posits that agreement (i.e., congruence) between two psychological variables is likely to be related to an outcome variable (Humberg et al 2019).
Traditional methods use difference scores (e.g., absolute differences or squared differences) between two psychological variables to predict outcome variables (Glass and Polisar 1987, Rogers et  When polynomial regression with response surface analysis is used to understand the relationships between the level of agreement between dyads (e.g., husband's climate change risk perception X and wife's climate change risk perception Y) and one outcome variable Z (e.g., turning off lights when leaving a room), the data from the three variables (X, Y, and Z) are plotted in three-dimensional space, and the relationship among X, Y, and Z is examined using polynomial regression and the graphical response surface (Barranti et al 2017).
The polynomial regression model is written as follows (Edwards and Parry 1993): By examining the following three elements obtained from the polynomial regression model, researchers can investigate congruence effects (Humberg et al 2019) in terms of the first principal axis, the line of congruence (LOC), and the line of incongruence (LOIC).The first principal axis represents the ridge of the surface, and the projection of the first principal axis onto the XY plane indicates whether the position of the first principal axis differs significantly from that of the LOC, which indicates the congruence of predictors X and Y (Schönbrodt et al 2018, Tsai et al 2022).When the position of the first principal axis does not significantly differ from that of the LOC, the outcome variable Z is predicted by the dyadic predictors.The equation for the first principal axis on the XY plane is: Y = p 10 + p 11 X, and when the following two conditions are met, the position of the first principal axis does not significantly differ from that of the LOC (Humberg et al 2019): (1) p 10 does not significantly differ from 0, and (2) the confidence interval p 11 includes 1.
When the position of the first principal axis does not significantly differ from that of the LOC, researchers must examine whether different incongruent predictor combinations result in significant lower outcome values to determine a congruence effect (Humberg et al 2019).The LOIC, the line perpendicular to the LOC, is used for this.The value of Y is set as −X in the polynomial regression model and the following equation is used (Humberg et al 2019 is usually abbreviated as a 4 (Shanock et al 2010).A congruence effect exists when the LOIC has an inverted U shape that peaks at (0, 0) (Schönbrodt et al 2018).To meet this requirement, a 3 should not differ significantly from 0, and a 4 must be significantly negative (Humberg et al 2019).
When the requirements of p 10 , p 11 , a , 3 and a 4 are met, a broad congruence effect is exhibited because the predictors exert main effects on the outcome variable (Humberg and Grund 2022).Two additional parameters, a 1 and a , 2 help explain the types of main effects.Variables a 1 and a 2 can be calculated by setting the value of Y as X in the polynomial regression model, and thus = +

Methods and context
This study enlisted the help of a research center (Global Views Survey Research Center) to administer a face-to-face survey to married heterosexual couples who were registered residents of Taipei City, Taiwan.The research was conducted from 12 March to 6 April, 2019.This study was approved by the Research Ethics Committee at National Taiwan Normal University (NO: 201808HS001), and study procedures were performed in accordance with relevant guidelines and regulations.The same dataset has been used by Hung and Bayrak (2019) and Hung and Wang (2022a).Therefore, only brief descriptions of the survey data are discussed here, whereas the studies of Hung and Bayrak (2019) and Hung and Wang (2022a) discuss the sample characteristics and survey questions in detail.

Sample selection and survey distribution
In total, 152 married, heterosexual couples participated in this survey.Stratified proportional sampling was used.Survey samples were collected from all 12 districts of Taipei City, with the number of married couples surveyed proportionate to the number of households in a district in relation to the entire city.Trained interviewers approached people on the streets of each district who seemed to be heterosexual couples, asking them if they were married and living together in a district of Taipei City.
Both spouses had to be at least 20 years old to participate in the survey on household climate change mitigation behavior.Participants presented their identification cards to verify their legal marriage status.All participants' signatures were collected on consent forms before the couples completed the paper-based survey.After completing the survey, the respondents received a gift card worth NT$200 (US$6.44).To ensure a diverse and balanced sample, the surveyed couples were selected by the research team on the basis of age.In half of the surveyed couples, the husband was 50 years old or older.

Sample selection and survey distribution
The survey comprised a joint questionnaire and an individual questionnaire.The couples first answered the joint questionnaire and then individually completed a second questionnaire.Because individual-level reports of household proenvironmental behaviors have representativity problems (Seebauer et al 2017), spouses were asked to discuss their answers to the joint survey questions and were required to reach a consensus on each question before proceeding to the next.The individual spouse surveys were identical, and the participants were asked not to discuss the survey questions and answers with their spouses when completing the survey.
Questions regarding household-level engagement in three types of climate change mitigation behaviors used by previous studies were included in the joint survey (Semenza et al 2008, Whitmarsh 2009, Brody et al 2012, Seebauer et al 2017, Hung and Wang 2022b): not turning on the air conditioner, using public transportation, and buying energyefficient appliances (table 1).These three types of climate change mitigation behaviors were chosen because household energy usage and daily transportation are important contributors to household carbon footprints (Seebauer et al 2017, Lacroix 2018).Respondents reported their frequency of engagement in these mitigation behaviors on a 5-point scale, ranging from 1 (never exhibiting this behavior) to 5 (always exhibiting this behavior).
Household-level variables were also collected in the joint survey.These variables included household size (mean = 4, standard deviation = .8),annual household income for 2018 (39% reported having an annual income between NT$1 million and 1.5 million (or US$32,613 and US$48,920 respectively), and whether the household had children younger than 18 years old (of which 53% of the households did).
Several questions regarding determinants of climate change mitigation behavior were asked in the individual survey.These determinants included individual-level determinants discussed in previous studies (Brody et al 2012, Hung and Bayrak 2019, Hung and Wang 2022b) and household-level determinants (Heath and Gifford 2002, Grønhøj 2006, Hung and Wang 2022a).Individual-level determinants included climate change risk perception, environmental attitudes, self-efficacy, attributed responsibility for mitigation, and motivation for behavioral change to mitigate climate change.Household-level determinants included gender norms, perceived difficulty in engaging in mitigation behavior, and perceived conflict in engaging in mitigation behavior.The determinants and questions belonging to these determinants as well as the respondents' scores and references to these determinants are shown in table 2. The questions were all assessed using 5-point Likert scales.To facilitate interpretation, questions on the determinants of gender norms, perceived difficulty, attributed responsibility, perceived conflict, and environmental attitudes were reverse-coded.In many studies, higher scores were indicative of higher environmental attitudes.However, the indicators for environmental attitudes used in this study were based on the human exceptionalism paradigm, the notion that humans are exempt from the constraints of nature (Dunlap et al 2000).Thus, questions on environmental attitudes were reverse-coded.Agreement with the statement used to measure gender norms, 'a man's job is to earn money, and a women's job is to look after the home and family,' was correlated weakly but significantly and negatively with motivation for behavioral change to mitigate climate change in a previous Taiwanese study (Hung and Bayrak 2022).Thus, the question on gender norms was also reverse coded.

Data analysis
Polynomial regression with response surface analysis was conducted using the RSA package in R (Schönbrodt et  3 are met.On the basis of the results of previous studies (discussed in the literature review), seven of the eight determinants were expected to be positively correlated with the outcome variables: self-efficacy, climate change risk perception, motivation for behavioral change to mitigate climate change, environmental attitudes (reverse-coded), perceived difficulty of climate change mitigation (reversecoded), perceived conflict (reverse-coded), and attributed responsibility for mitigation (reverse-coded).Therefore, the study hypothesized that these seven factors would exhibit a broad congruence effect.Because Greenstein (1996) indicated that the interaction of gender norms held by family members influences household behavior, gender norms were hypothesized to exhibit a strict congruence effect.

Research context
In assessments of countries' vulnerability to the combined hazard risk of cyclones, floods, earthquakes, and landslides, Taiwan is consistently ranked as among the most vulnerable (UNISDR 2009, Lin and Polsky 2016).According to Taiwan's Council for Economic Planning and Development, climate change in Taiwan is expected to manifest in several manners.Temperature and associated heat waves will increase.Rainy seasons will feature increasing precipitation, whereas dry seasons will exhibit decreasing precipitation.Additionally, although the number of typhoons impacting Taiwan is declining, the intensity of typhoons and the associated extreme rainfall will likely increase (CPED 2012).Therefore, climate change poses a serious challenge to Taiwan.Because Taipei City-the nation's capital consisting of almost 3 million inhabitants-lies in a basin and features a densely built environment, it is particularly vulnerable to an aggravated urban heat island effect and floodwater discharge caused by rising sea levels.In this study, most residents of Taipei were assumed, to a more or less degree, to be aware of climate change because of the city's high exposure to climate-related hazards and risks (Hung and Bayrak 2019).Therefore, Taipei City was selected as the geographical unit of this study.

Results
The dyadic relations between eight determinants and three household climate change mitigation behaviors assessed using response surface analysis with polynomial regression are presented in tables 3-5.In the second row of these tables, the conditions for congruence are presented (adopted from Brauner et al 2020).The response surface plots are presented in figures 1-3.

Prediction of air conditioner nonuse
The numerical scores for the relationship between husband-wife congruence and not turning on air conditioners are shown in table 3, and the corresponding graphical results are shown in figure 1.None of the eight determinants exerted congruence effects on the dependent variable.The conditions for p 10 and p 11 were met for self-efficacy, environmental attitudes, and perceived difficulty, indicating that, for the aforementioned variables, husband-wife agreement can predict reported engagement in the household behavior of not turning on the air conditioner.However, because none of these three determinants met the requirements of a 3 and a 4 , none of the eight determinants fulfilled the conditions indicating congruence effects.For variables other than self-efficacy and attributed responsibility, the values of a 4 were not negative, suggesting that the surface above the LOIC for these six variables did not exhibit the expected inverted U shape.Furthermore, because none of the eight variables met the conditions for a broad congruence effect, the values of a 1 and a 2 were not further examined for strict congruence effects.

Prediction of public transportation use
The numerical scores for relationships husband-wife congruence and public transportation use are shown in table 4, and the corresponding graphical results are shown in figure 2. None of the eight determinants exerted congruence effects on the dependent variable.The self-efficacy and gender norms determinants met the p 10 and p 11 value requirements.The value of p 10 for risk perception differed significantly from 0, indicating that congruent determinants did not predict highest reported public transportation use.The confidence interval of p 11 for risk perception, motivation, environmental attitudes, perceived difficulty, attributed responsibility, and perceived conflict did not include 1, indicating that the first principal axis was not parallel with the LOC.However, the self-efficacy and gender norms determinants did not satisfy the requirements of a 3 and a 4 because they did not have statistically negative values, indicating that higher incongruence not correspond with lower reported public transportation use.Because none of the eight determinants fulfilled the conditions for broad congruence effects, the values of a 1 and a 2 were not further examined strict congruence effects.

Prediction of purchase of energy-efficient appliances
The numerical scores for the relationship between husband-wife variables and the purchase of energy-efficient appliances are shown in table 5, and the corresponding graphical results are shown in figure 3. The determinants of self-efficacy, risk perception, motivation, gender norms, attributed responsibility, and perceived conflict met the requirements of p 10 and p 11 , suggesting that husband-wife congruence in these determinants leads to the highest reported engagement in the purchase of energy-efficient appliances.The values of a 3 and a 4 for these six determinants were further examined, and those of gender norms and attributed responsibility satisfied the conditions of a 3 and a 4 , with nonsignificant a 3 values and statistically negative a 4 values.The determinants of gender norms and attributed responsibility fulfilled the conditions of p 10 , p 11 , a 3 , and a 4 , exhibiting a broad congruence effect.Subsequently, the values of a 1 and a 2 for gender norms and attributed responsibility were examined.For both gender norms and attributed responsibility, the values of a 1 and a 2 were not statistically significant, suggesting that the two determinants exhibited strict congruence effects.Thus, couples whose gender norms and attributed responsibility were congruent reported the same level of engagement in buying energy-efficient appliances.

Discussion
In this study, the congruence effects of married heterosexual couples' psychological determinants on household climate change mitigation behaviors were examined.In predicting three household climate change mitigation behaviors (not turning on air conditioners, using public transportation, and buying energy-efficient appliances), none of the individual-level determinants (climate change risk perception, environmental attitudes, selfefficacy, motivation for behavioral change to mitigate climate change, or attributed responsibility for mitigation) exhibited congruence effects; however, two household-level determinants of household climate change mitigation behaviors exhibited congruence effects: gender norms and attributed responsibility for climate change mitigation, both of which exerted congruence effects on energy-efficient appliance purchasing.
The results of this study partially support the importance of husband-wife congruence in performance of household climate change mitigation behavior.Compared with that of individual-level variables, the agreement of household-level variables between husband and wife were more likely to affect engagement in household climate change mitigation behavior.This is consistent with previous studies such as that of Grønhøj (2006) Gender norms exhibited strict congruence effects, as expected.Consideration of the interaction of husband and wife gender norms on family behaviors is crucial (Greenstein 1996, Cheung andChoi 2016), and congruence of gender norms between couples result in outcomes such as having a child together (Hudde and Engelhardt 2020).The results of this study support these findings and indicate that congruence in gender norms between husband and wife are associated with engagement in climate change mitigation behavior.
Nevertheless, attributed responsibility for climate change mitigation did not meet expectations of exhibiting a broad congruence effect with linear main effects; it instead exhibited a strict congruence effect.This indicates that when agreement exists between husband and wife on perceived responsibility for climate change mitigation, regardless of agreement on perceived family responsibility or perceived government responsibility, couples report higher engagement in buying energy-efficient appliances.Explanation of the congruence effects of perceived government responsibility on buying energy-efficient appliances requires further investigation, but it is likely that the reasons for the congruence effects of perceived family responsibility on mitigation behavior (e.g., environmental considerations such as mitigating climate change) differ from those for the congruence effects of perceived government responsibility (e.g., economic reasons such as saving money in the long term).
None of the determinants exerted congruence effects on the mitigation behaviors of not turning on air conditioners and using public transportation.Engagement in these mitigation behaviors may tend to be individually decided and require levels of household interaction.The literature on household decisionmaking indicates that decisions regarding household tasks can be joint or individual decisions (Belch et al 1985, Acosta et al 2020).A qualitative study on the use of air-conditioning found that interviewees expressed the necessity of turning on air conditioners for their own or family members' comfort when they were able to afford doing so (Nicholls and Strengers 2014).In these cases, individuals considered acting for themselves or their family members, and other family members may have passively accepted these individual decisions.Thus, conversations regarding air-conditioning among family members may be limited.Another possible reason is that performing these two mitigation behaviors is conditioned by contextual factors, meaning that the agreement of family members is not a primary factor in engagement in these behaviors.For example, many travel behaviors are influenced by time, convenience, or habit, which may cause individuals to perceive that using public transportation is not possible (Vredin Johansson et al 2006, Ho and Mulley 2015, Moberg et al 2021).Conversely, families without personal vehicles must rely on public transportation when traveling regardless of attitudinal agreement regarding related variables.
For future studies, researchers should consider using similar methods to understand the congruence effects of household climate change related behaviors in contexts other than the urban East Asian context in which this study was embedded in.Because social, cultural, racial, and ethnic contexts influence family and household dynamics (McLanahan and Percheski 2008, Hung et al 2016, Hung and Wang 2022a), similar studies should be conducted in different contexts to improve our understanding of how context influences congruence effects on household mitigation behaviors.

Conclusion
Congruence in household-level variables between husband and wife could be key to engagement in household mitigation behaviors that requires a certain level of intrahousehold interaction.Because families and households are the basic units of society and are associated with considerable greenhouse gas emissions, more studies are necessary to understand how intrahousehold dynamics-including factors such as congruence effectsmanifest in mitigation behavior engagement.
et al 2019).When neither a 1 nor a 2 differ significantly from 0, the value of Z does not change when X and Y have congruent values, regardless of whether the values of X and Y are both low or high; a positive a 1 value and a nonsignificant a 2 value suggest that high (low) X and Y values predict a high (low) Z value; a significant positive or negative a 2 value indicates a curvilinear relationship (Humberg et al 2019, Humberg and Grund 2022).

Figure 1 .
Figure 1.Response surfaces for prediction of air conditioner nonuse.

Figure 2 .
Figure 2. Response surface for prediction of public transportation use.

Figure 3 .
Figure 3. Response surface for prediction of purchase of energy-efficient appliances.
, which suggested that during communication regarding engagement in mitigation behaviors, environmental factors (e.g., climate change risk perception or environmental attitudes in this study) are not usually crucial.Instead, factors such as time, economy, taste, and convenience (Grønhøj 2006) and factors related to household decision-making (Hung 2018) are more likely to be salient in engagement in household climate change mitigation behavior.Therefore, although individual-level determinants, such as climate change risk perception or self-efficacy, are theoretically associated with engagement in household climate change mitigation behavior (Brody et al 2012), these individual-level determinants do not exhibit congruence effects.By contrast, household-level determinants, including gender norms and attributed responsibility for climate change in this study, exert congruence effects on engagement in mitigation behaviors.
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Sociol 34 257-76 Moberg K R et al 2021 Barriers, emotions, and motivational levers for lifestyle transformation in Norwegian household decarbonization pathways Clim.Change 165 3 al 2018), but these methods have several methodological problems such as low reliability, ambiguous interpretation, confounding effects, untested constraints, and dimensional reduction (Edwards 2002).Polynomial regression with response surface analysis has been used to overcome these problems and test congruence effects (Brauner et al 2020, Bragger et al 2021).Many studies have discussed this method in detail (Edwards and Parry 1993, Edwards 2002, Shanock et al 2010, Barranti et al 2017, Schönbrodt et al 2018, Humberg et al 2019, Humberg and Grund 2022, Tsai et al 2022).Here, a brief introduction to polynomial regression with response surface analysis is provided as follows:

Table 1 .
Household climate change mitigation behavior.

Table 2 .
Determinants used in this study.(R)denotes reverse coded variables, and means and standard deviations for these variables are values after reverse coding.
al 2018).The protocol discussed by Barranti et al (2017) was followed.As suggested by previous studies (Edwards and Cable 2009, Shanock et al 2010), all variables were centered by subtracting the scale midpoint (i.e., 2.5 points) prior to polynomial regression and response surface generation.The checklists provided by Humberg et al (2019) were used to investigate whether congruence effects existed.Humberg et al (2019) demonstrated two types of congruence effect: (1) a strict congruence effect, when

Table 3 .
Response surface results for predictors of air conditioner nonuse.

Table 4 .
Response surface results for predictors of public transportation use.

Table 5 .
Response surface results for predictors of purchase of energy-efficient appliances.