Making the Customer Orientation of Salespeople Unsustainable — The Moderating Effect of Emotional Exhaustion

Customer orientation of salespeople usually leads to a sustainable positive effect on job performance, yet previous research has usually focused on the benefits of functional customer orientation, and less is known about its relational customer orientation’s outcomes. Based on conservation of resources theory, this research focuses on both types of customer orientation, functional and relational customer orientation, and investigates the moderating effect of emotional exhaustion on the relationship between customer orientation and adaptive selling behavior. We collected 282 valid questionnaires from frontline salespeople in China. Results showed that functional/relational customer orientation was positively correlated with salespeople’s adaptive selling behavior. Salespeople’s emotional exhaustion moderates the main effect: when emotional exhaustion is high, the relationship between functional/relational customer orientation and adaptive selling behavior is substantially weakened. This study contributes to a further understanding of the sustainable operation environment for customer orientation, and provides practical implications regarding the attainment of sustainable outcomes of customer orientation.


Introduction
Highly diverse customer demand drives managers that are eager to know what customers think and want.Customer orientation is an effective way to gain sustainable profit for the company [1,2].Contrary to selling orientation, customer orientation emphasizes meeting the customers' needs and avoids sacrificing customer benefit for long-term customer relationships [3], which usually leads to high job performance in a sustainable way [4,5].
Previous research dominantly focuses on the sustainable job outcome of customer orientation, such as job performance [4,5]; less is known about suitable environments of customer orientation, which are critical for salespeople to practice their customer orientation.Furthermore, previous studies stress the importance of functional customer orientation, which is defined as salespeople acting in the role of businessmen, identifying needs and explaining and recommending products to customers [1,6], but place less emphasis on relational customer orientation, which is defined as salespeople acting as friends building personal relationships with customers [7,8].Maintaining a close relationship with customers is very important for salespeople, especially in China, because Chinese individuals' relationships (i.e., guanxi) have instrumental attributes, and products in China are usually sold on the basis of friendship [9].Additionally, previous studies found that salespeople's customer orientation has mixed effects on performance outcomes [10,11], and functional (vs.relational) customer orientation produces a different effect on the creativity of salespeople [8].Therefore, we specifically classify customer orientation into functional customer orientation and relational customer orientation in order to locate its different influences.
Implementing customer orientation requires plenty of resources [3,12].The biggest challenge is not whether to choose the customer orientation strategy or not, but how to make customer orientation sustainable, to balance the input resources and the output of performance, and to create a sustainable environment for customer orientation operation.Due to stressful job requirements, salespeople are very susceptible to losing functional or emotional resources.Based on conservation of resource theory [13], individuals have natural instincts to preserve and protect resources (e.g., personal mental resources and workplace resources), especially when those valued resources are at risk of being lost or are already lost.When losing resources or not getting enough supplementation after investing resources, people feel mentally stressed [14].Long lasting resource deficits lead to emotional exhaustion, a serious affective and chronic type of work strain [15,16], which decreases service performance and customer satisfaction [14,17].
Considering salespeople's high sales quota and heavy mental resource usage, it is critical to consider the level of emotional exhaustion of salespeople when managers expect more sustainable outcomes of salespeople's customer orientation.Previous research has found that customer orientation positively influenced salespeople's job performance [18], increased customer purchase likelihood, and increased customer relationship continuity [19].However, researchers also found that higher customer orientation does not always produce higher performance; instead it is an inverted U-shaped effect [3,12].It may result from situational moderating factors (e.g., product individuality and supplier price positioning) [12] and improper use of cross-sectional performance [20].Compared to job performance, adaptive selling behavior is a better way to measure the outcome of customer orientation, because it represents salespeople using extra resources to adopt different influence tactics for different kinds of customers [21] and a strong prediction index of customer satisfaction and future interaction [22,23].
Therefore, our research is aimed at finding out how functional/relational customer orientation of salespeople affects their adaptive selling behavior, and how emotional exhaustion moderates these main effects.We collected 282 valid questionnaires from front-line salespeople in 16 different companies in China to address these questions.Our research will contribute to the studies of sustainable company profits and sustainable sales resources in the future.

Functional Customer Orientation Influences Adaptive Selling Behavior
Contrary to selling orientation, customer orientation emphasizes meeting customers' needs, avoiding the use of high pressure skills to sacrifice customer benefit, and aiming for long-term customer satisfaction [1].Academic researchers used to take customer orientation as a single dimension construct until Homburg et al. (2011) [7] clearly distinguished functional customer orientation and relational customer orientation according to role theory [24,25].Functional customer orientation refers to salespeople acting as a business person [7].Adaptive selling behavior refers to salespeople quickly and precisely altering their sales presentation and actions when interacting with different customers and different sales situations [26].We think functional customer orientation is positively related to adaptive selling behavior for the following reasons: Functional customer orientation will increase salespeople's autonomous service motivation and result in more adaptive selling behaviors.Compared to company customer orientation, which contains more controlled motivation, employee customer orientation includes more autonomous motivation [11].When salespeople have high functional customer orientation, they are more willing to help customers solve their problems and more likely to adopt adaptive selling behaviors, compared with low functional customer orientation.
Additionally, compared to salespeople who have low functional customer orientation, salespeople who have high functional customer orientation are more willing to study related skills to increase their adaptive selling behavior, because researchers found that salespeople who have more regulatory knowledge have higher job performance [27].We think salespeople who have high functional customer orientation care more about efficiently solving customer's problems, so they are willing to invest more resources in learning related selling skills, resulting in more adaptive selling behaviors, compared with low functional customer orientation.
Lastly, for customers, high functional customer orientation will stimulate customers to give more informative feedback, giving more chance for salespeople to use adaptive selling behavior.Researchers found that functional customer orientation will increase customers' willingness to share competitive information [28] and enhance customers' perceived relationship quality and intention to continue relationships [29].We think those customer cooperation actions will provide more opportunity for salespeople to perform their adaptive selling behaviors.Therefore, we propose the following: Hypothesis 1 (H1).Functional customer orientation of salespeople is positively related to adaptive selling behavior.

Relational Customer Orientation Influences Adaptive Selling Behavior
Although the concept of relational selling is very important in a marketing context [30], relational customer orientation was not proposed until Homburg et al. (2011) [7] defined it in 2011.Compared with functional customer orientation, which focuses on tasks, relational customer orientation refers to salespeople acting as a friend, for example, talking about personal interests, shared experiences, and establishing personal relationships [8].We think relational customer orientation has a positive influence on adaptive selling behavior for the following reasons: Firstly, in the genetic and neurological view of customer orientation, researchers found that salespeople who have higher relational customer orientation also experience greater activation of mirror neurons, which usually shows more empathy to others [31].Furthermore, compared to functional customer orientation, relational customer orientation is more related with personal traits of salespeople who are prone to feeling compassion [32].Highly relational customer orientation means more sensitivity to customers' emotional situation and more empathy towards customers' problems, and such salespeople are more likely to adopt adaptive selling behaviors, compared with those who have low relational customer orientation.
Secondly, higher relational customer orientation will enhance customers' trust and cooperative intentions, producing a greater chance for salespeople to use adaptive selling behaviors.Researchers found that the trust of a salesperson greatly influenced customers' anticipated future interactions [33].The higher the relational customer orientation, the more customers felt they were treated ethically, and the greater the purchase intention [34].Furthermore, salespeople's emotional intelligence and empathy, which are highly related with relational customer orientation, have a positive influence on customer participation [35].Friend et al. (2018) [32] found that relational customer orientation can positively transform a customer's propensity to trust salespeople into actually trusting salespeople.Therefore, we propose the following: Hypothesis 2 (H2).Relational customer orientation of salespeople is positively related to higher adaptive selling behaviors.

The Moderating Effect of Emotional Exhaustion for Functional Customer Orientation
Emotional exhaustion occurs when individuals' emotions are strained excessively by contact with others [36].When salespeople are emotionally exhausted, they feel their physical and psychological resources are depleted and are unable to express themselves in a sustainable way [37].
Salespeople who are emotionally exhausted lack enough cognitional resources to transform their functional customer orientation mindset into adaptive selling behaviors.Researchers found that the more job burnout employees experienced, the more their three main cognitive functions (executive functions, attention, and memory) declined [38]; also, the higher the emotional exhaustion, the more unethical behaviors they were engaged in [39].Based on the resource of reservation theory [13], this resource deficit situation will impair customers' inner server motivation, create an unwillingness to use extra resources to study more selling skills, and reduce adaptive selling behaviors.A previous study also found that the highest level of functional customer orientation diminished sales performance for it used too many of the salesperson's resources [3].
In addition, when salespeople are highly emotionally exhausted, customers will revalue their cooperation willingness and supply less information to salespeople.Because customers can sensitively perceive the emotional state of salespeople face to face, the higher emotional exhaustion of salespeople will impair customers' perceived service quality [40] and customer satisfaction [14], which in turn diminishes the opportunity for the adaptive selling behaviors of salespeople.Furthermore, research found that the psychological resourcefulness of salespeople increased their willingness to perform customer orientation [18].Therefore, when salespeople are highly emotionally exhausted, they are more willing to preserve their limited cognitive resources.Therefore, we propose the following: Hypothesis 3 (H3).Emotional exhaustion will moderate the relationship between functional customer orientation and adaptive selling behaviors.Specifically, the relationship between functional customer orientation and adaptive selling behaviors is weaker for salespeople with higher emotional exhaustion than those with lower emotional exhaustion.

The Moderating Effect of Emotional Exhaustion for Relational Customer Orientation
When salespeople feel emotionally exhausted and worry about their potential emotional resource loss, they will try to stop further resource loss and preserve their own limited emotional resources, based on resource of reservation theory [41].Furthermore, establishing personal relationships with customers usually requires salespeople to invest more emotional resources, and this kind of relationship is usually not required by company rules and is hard to measure [8].Although relational customer orientation creates greater empathy for customers, emotional exhaustion will decrease the salespeople's perception of others' discomfort [42] and weaken the positive relationship between relational customer orientation and adaptive selling behaviors.
In addition, when salespeople lack enough emotional resources, customers will perceive that they have little interest in their emotional state and less motivation to establish personal relationships, resulting in less customer satisfaction [14].The higher the emotional exhaustion of salespeople is, the less willingness to provide relational information a customer has, resulting in less opportunity for salespeople to perform adaptive selling behaviors.Researchers have shown that the more job burnout employees have, the lower job the performance and the higher the job departure intention they exhibit [43].We infer that the more emotional exhaustion salespeople have, the less they are willing to transform relational customer orientation into adaptive selling behaviors, because those adjusted selling actions require more emotional resources, which they lack.Therefore, we propose the following: Hypothesis 4 (H4).Emotional exhaustion will moderate the relationship between relational customer orientation of salespeople and adaptive selling behavior.Specifically, the relationship between relational customer orientation and adaptive selling behaviors is weaker for salespeople with higher emotional exhaustion than those with lower emotional exhaustion.
In summary, we propose the functional/relational customer orientation will be positively related to adaptive selling behavior, and this positive effect is moderated by emotional exhaustion level.The conceptual model of these hypotheses is shown in Figure 1.
relational customer orientation and adaptive selling behaviors is weaker for salespeople with higher emotional exhaustion than those with lower emotional exhaustion.
In summary, we propose the functional/relational customer orientation will be positively related to adaptive selling behavior, and this positive effect is moderated by emotional exhaustion level.The conceptual model of these hypotheses is shown in Figure 1.

Participants and Procedures
To test our hypotheses, we collected data by delivering self-administered questionnaires to front-line salespeople.We first contacted the sales managers and senior human resource executives of some companies via telephone and email, expressed our intention, and asked for their permission.We gave them a brief introduction to this investigation process and told them we required their assistance.Some companies' CEOs or managers knew our authors, which facilitated acceptance.At last, a total of 16 companies agreed to participate; they included companies from furniture, household appliances, finance, and software industries, among others.These companies' headquarters are in the Guangdong province in China.The salespeople involved in the survey are distributed throughout Guangdong, Anhui, Fujian, and other places.
Before formal investigation, we used G*Power software to determine our sample size [44].According to a meta-analysis of Frank and Park (2006) [45], the average effect size involving the relationship between customer orientation and adaptive selling behaviors was 0.26.Using the software, we found that, given an α error probability of 0.05, power is 0.80.Results showed that we should investigate at least 119 salespeople for a one-dimensional study; therefore, for a both two-dimensional study, we needed more than 238 salespeople.Furthermore, according to Comrey (1988) [46], a sample size of 200 is good for an ordinary factor analysis with 40 or fewer test items.We had fewer than 40 test items in the

Participants and Procedures
To test our hypotheses, we collected data by delivering self-administered questionnaires to front-line salespeople.We first contacted the sales managers and senior human resource executives of some companies via telephone and email, expressed our intention, and asked for their permission.We gave them a brief introduction to this investigation process and told them we required their assistance.Some companies' CEOs or managers knew our authors, which facilitated acceptance.At last, a total of 16 companies agreed to participate; they included companies from furniture, household appliances, finance, and software industries, among others.These companies' headquarters are in the Guangdong province in China.The salespeople involved in the survey are distributed throughout Guangdong, Anhui, Fujian, and other places.
Before formal investigation, we used G*Power software to determine our sample size [44].According to a meta-analysis of Frank and Park (2006) [45], the average effect size involving the relationship between customer orientation and adaptive selling behaviors was 0.26.Using the software, we found that, given an α error probability of 0.05, power is 0.80.Results showed that we should investigate at least 119 salespeople for a one-dimensional study; therefore, for a both two-dimensional study, we needed more than 238 salespeople.Furthermore, according to Comrey (1988) [46], a sample size of 200 is good for an ordinary factor analysis with 40 or fewer test items.We had fewer than 40 test items in the questionnaires.We prepared to collect more than 250 samples to adequately power the key customer orientation (functional/relational) × emotional exhaustion interaction.
Because front-line salespeople usually work in different sales sections and not always indoors, it is hard to investigate all salespeople at the same time.We randomly selected several selling departments of the company from a list of all selling departments, and we then visited the chosen departments.With the help of department managers, we acquired a list of salespeople's names.For those who stayed on site, we distributed and retrieved questionnaires as soon as salespeople filled them in.For those who were not on site, we contacted them by online survey.We sent the online website link to the managers, let them transmit the website links to the rest of the salespeople, and asked them to fill it in.During the process, we promised that the survey data would only be used for academic research, and we would keep the information anonymous.
For data collected on the site, we sent out 250 questionnaires in total, received 225 back, excluded questionnaires with incomplete data and obvious errors, and ended up with 211 valid questionnaires.For data collected online, we sent out 80 questionnaires and received 71 valid questionnaires.Therefore, the final total was 282 questionnaires, resulting in a response rate of 85.5%.
Table 1 presents demographics of the sample.

Measures
In this study, we translated English scales into Chinese type.All items were measured by a seven-point Likert scale ranging from 1 = "highly disagree" to 7 = "highly agree".We have listed the measurement items in Appendix A.
Functional customer orientation.We measured functional customer orientation using a nine-item scale that was adapted from Homburg et al. (2011) [7].Sample items are as follows: "I ask my customer about their specific performance requirements" and "I focus on functional information which is especially relevant for my customers."The Cronbach's alpha for this scale was 0.88.
Relational customer orientation.We measured functional customer orientation using a four-item scale that was also adapted from Homburg et al. (2011) [7].Sample items are as follows: "In sales conversations, I establish a personal relationship with my customers" and "I often point out things I have in common with my customers (e.g., common interests, experiences, and attitudes)."The Cronbach's alpha for this scale was 0.83.
Emotional exhaustion.We measured emotional exhaustion using a four-item scale that was adapted from Maslach and Jackson (1981) [37].Sample items are as follows: "I feel emotionally drained from my work" and "I feel used up at the end of the workday".The Cronbach's alpha for this scale was 0.83.
Adaptive selling behavior.We measured adaptive selling behavior using a three-item scale that was adapted from Piercy et al. (2009) [47].Sample items are as follows: "I am flexible in sales approaches used" and "I adapt sales approaches from one customer to another."The Cronbach's alpha for this scale was 0.93.
Control variables.We controlled salespeople's age, gender, education, working tenure, and tenure with their superior in this study.We measured those control variables using a dummy variable, which codes male as "1" and female as "2"; age is labeled from "1" to "7"; education is labeled from "1" to "5"; work tenure is labeled from "1" to "5"; work tenure with superior is labeled from "1" to "5." The descriptive statistics analysis of these control variables is shown in Table 1.

Descriptive Statistics and Inter-Correlations between Variables
We use SPSS 22.0 to analyze our data.The mean, standard deviation, and correlation of variables are reported in Table 2.In Table 2, functional customer orientation is significantly positive with respect to adaptive selling behavior (r = 0.66, p < 0.01), relational customer orientation is significantly positive with respect to adaptive selling behavior (r = 0.46, p < 0.01), and emotional exhaustion is significantly negative with respect to adaptive selling behavior (r = −0.19,p < 0.01).

Reliability and Validity
We use Cronbach's alpha and composite reliability (CR) to measure the reliability of scale.According to Cortina (1993) [48], Cronbach's alpha value above 0.70 is acceptable; all Cronbach's alpha values of our constructs are higher than 0.80, showing good reliability.In addition, according to Hair et al. (2013) [49], composite reliability greater than 0.70 is acceptable; all our CR values of construct meet this standard.
We also assessed scale's validity, using convergent validity and discriminate validity as indices.First, we computed each construct's average variance extracted (AVE) value to measure convergent validity and found that all AVE values are higher than 0.50, suggesting that these constructs have good convergent validity, according to the standard of Fornell and Larcker (2010) [50].We show Cronbach's alpha, CR, and AVE in Table 3.Following Fornell and Larcker (2010) [50], we use a square root of AVE greater than the inter-construct correlation to measure discriminant validity.As seen in Table 4, the square root of the AVE value is greater than the correlation of each construct, showing our scale has good discriminate validity.Lastly, we conducted confirmatory factor analysis to confirm that our four-factor model is the most suitable for analysis.We used Amos 22.0 to conduct confirmatory factor analysis, linked each item with its intended construct, and freely estimated the covariance among constructs.Usually, the acceptable standard for SRMR is less than 0.08 [51], for X 2 /df is less than 3.0 [52], for GFI/NFI/TLI/CFI is more than 0.90 [53], and for RESEA is less than 0.70 [54].From Table 5, we can see only the four-factor model is the best fit, meeting all requirements of cutoff criteria.

Results
We used several hierarchical linear regressions to verify our hypotheses.Those results are presented in Tables 6 and 7. First, we standardized all control variables, independent variables, and moderator variables, and we then used SPSS to verify our hypothesis.At last, we used the bootstrap process of Hayes to test our moderator effect.
Furthermore, we used Harman's single factor method to show our data does not have a serious common method bias.We loaded all variables into the factor analysis, but constrained the number of factor to "1."The first component of the total variance explained is 37.98%, less than 50%, showing that there is no substantial common method bias presence in the data [55].As seen in Table 4, in Model 1, we first entered standardized control variables including age, gender, education, working tenure, and working tenure with superior.In Model 2, we entered standardized independent and moderator variables.It shows functional customer orientation is positively related to adaptive selling behavior (β = 0.704, p < 0.001), supporting H1.In Model 3, we entered standardized functional customer orientation × emotional exhaustion to test its moderating effect and found that the interaction of functional customer orientation and emotional exhaustion reveals a significant impact on adaptive selling behavior (β = −0.156,p < 0.05), supporting H3.Furthermore, we used the Hayes process to test our moderator model, bootstrapping 2000 samples.The result supports H1, that higher functional customer orientation leads to more adaptive selling behavior (β = 0.6830, SE = 0.0651, 95% CI = [0.5548,0.8111]), and H3, that emotional exhaustion disrupts the positive relationship between functional customer orientation and adaptive selling behavior (β = −0.1564,SE = 0.0746, 95% CI = [−0.3033,−0.0095]).Figure 2 shows the moderating effect of emotional exhaustion on the relationship between functional customer orientation and adaptive selling behavior.We plus/minus one standard deviation from the mean emotional exhaustion score, in order to represent high/low emotional exhaustion.We used the same method to calculate the high/low functional customer orientation.emotional exhaustion.We used the same method to calculate the high/low functional customer orientation.Consistent with the steps above, we also conducted hierarchical linear regression analyses and bootstrapped the process to test Hypotheses 2 and 4.  Consistent with the steps above, we also conducted hierarchical linear regression analyses and bootstrapped the process to test Hypotheses 2 and 4.
Figure 3 shows the moderating effect of emotional exhaustion on the relationship between relational customer orientation and adaptive selling behavior.We plus/minus one standard deviation from the mean emotional exhaustion score in order to represent high/low emotional exhaustion.Figure 3 shows the moderating effect of emotional exhaustion on the relationship between relational customer orientation and adaptive selling behavior.We plus/minus one standard deviation from the mean emotional exhaustion score in order to represent high/low emotional exhaustion.

Results
This study examines when customer orientation of salespeople cannot sustainably lead to a positive job outcome.We first identified the relationship between functional/relational customer orientations with the adaptive selling behavior of salespeople, and then investigated whether emotional exhaustion moderates the main effect.Results of this study are as follows.
First, we show that not only functional customer orientation but also relational customer orientation produces more adaptive selling behavior.Second, this positive effect will be moderated by salespeople's emotional exhaustion level.When salespeople's emotional exhaustion level is high (vs.low), the positive effect between functional/relational customer orientation and adaptive selling behavior is substantially weakened.

Theory Contribution
First, we answer the calling of Homburg et al. (2011) [7] of more research on both types of customer orientation.They classified customer orientation into functional customer orientation and relational customer orientation according to their role in business.We found not only functional customer orientation but also rational customer orientation contributes to positive job outcomes, such as adaptive selling behaviors.Furthermore, our research explains why higher customer orientation leads to higher job performance [11,18], partly because higher customer orientation increases adaptive selling behaviors when salespeople interact with customers as shown in this paper.
Secondly, we also answer the challenge of discovering why salespeople's customer orientation does not always result in higher job outcomes.Our research shows it is influenced by the sustainability of salespeople's resources.Previous studies have shown that higher

Results
This study examines when customer orientation of salespeople cannot sustainably lead to a positive job outcome.We first identified the relationship between functional/relational customer orientations with the adaptive selling behavior of salespeople, and then investigated whether emotional exhaustion moderates the main effect.Results of this study are as follows.
First, we show that not only functional customer orientation but also relational customer orientation produces more adaptive selling behavior.Second, this positive effect will be moderated by salespeople's emotional exhaustion level.When salespeople's emotional exhaustion level is high (vs.low), the positive effect between functional/relational customer orientation and adaptive selling behavior is substantially weakened.

Theory Contribution
First, we answer the calling of Homburg et al. (2011) [7] of more research on both types of customer orientation.They classified customer orientation into functional customer orientation and relational customer orientation according to their role in business.We found not only functional customer orientation but also rational customer orientation contributes to positive job outcomes, such as adaptive selling behaviors.Furthermore, our research explains why higher customer orientation leads to higher job performance [11,18], partly because higher customer orientation increases adaptive selling behaviors when salespeople interact with customers as shown in this paper.
Secondly, we also answer the challenge of discovering why salespeople's customer orientation does not always result in higher job outcomes.Our research shows it is influenced by the sustainability of salespeople's resources.Previous studies have shown that higher salesperson customer orientation does not always produce higher job performance [12,56]; researchers have found contextual factors (e.g., product importance/competitive intensity) [12], a sales manager's ability to perceive emotions [3], and low job autonomy [57] influence the effect of salespeople's customer orientation on sales performance, impeding customer orientation from producing sustainable positive outcomes.However, we think it is also important to focus on the sustainable sales resources of salespeople because salespeople need many resources to operate their customer orientation mindset.Our research fills this gap and finds that a low level of salespeople's emotional exhaustion is a very critical factor in letting customer orientation take effect.

Implications
First, managers should put the same weight on developing salespeople's functional and relational customer orientation.In salespeople's training, companies usually put more stress on salespeople's functional customer orientation, such as ensuring salespeople have a wide knowledge about products and are patient when answering customer's questions, and they have lots of qualifying tests to make sure salespeople master enough knowledge.However, our research shows relational customer orientation also plays an important role in job behaviors, so measuring and testing salespeople's relational customer orientation should also be taken into consideration in training, and this would result in more sustainable profits.
Second, managers should focus on building a sustainable operational resource environment for salespeople and eliminate the factors that lead to the emotional exhaustion of sales staff, such as complicated reimbursement processes, a vague job role, indifferent job support atmosphere, etc., to provide a sustainable implementation environment for sustainable customer-oriented thinking.Managers cannot blindly emphasize customer orientation of salespeople without offering supporting resources.

Limitations and Future Study Suggestions
First, because of the high staff mobility of salespeople and the wide range of this investigation between different companies, we used the cross-section data and self-administered questionnaire.We tested the variance inflation factor (VIF) and found it was less than 3, which meant it was acceptable for analysis and had no serious multicollinearity problem.However, we do recommend researchers take the manager-rated performance for salespeople and use a longitude study in the future.Furthermore, the correlation values between the emotional exhaustion with others are at a low degree, and we guess that this may be because salespeople were motivated to manage their self-image, and did not completely trust that researchers would keep the information anonymous.Researchers can use other administration methods to value the level of emotional exhaustion of salespeople in the future.
Second, researchers can further explore the difference effect between functional versus relational customer orientation and find their different influences on job outcomes (e.g., job satisfaction, job turnover rate, and customer loyalty).In addition, researchers can investigate other moderate variables that may have positive effects on the relationship between functional customer orientation and job outcomes, but have a negative or no effect on the relationship between relational customer orientation and job outcomes.
Third, researchers can also focus on the dark side of customer orientation.Because customer orientation requires that salespeople care more about customer well-being and invest more resources in them, it not only increases the job burden of salespeople but also results in an excessive customer orientation, leading salespeople to substantially benefit customers but harm the company's interests, e.g., collaborating with customers to cheat on the salespeople's company and sending excessive gifts to customers.To this effect, Leo and Russell-Bennett (2014) [58] have already developed a multidimensional scale of customer-oriented deviance, so future studies can explore with which type of customer orientation and in which situations salespeople will perform such deviant customer orientation behavior.
Fourth, researchers can investigate how the customer orientation of salespeople influences value co-creation with customers and which type of customer orientation has a greater effect on customer participation behavior.Researchers found that customer orientation can increase the willingness of customers to share competitor information [28] and customer citizenship behavior [59], which are both types of customer value co-creation behavior [60].Therefore, we suggest that future researchers determine which types of customer orientation can produce the various types of customer value co-creation behaviors.

Figure 2 .
Figure 2. The moderating effect of emotional exhaustion on the relationship between functional customer orientation and adaptive selling behavior.

Figure 2 .
Figure 2. The moderating effect of emotional exhaustion on the relationship between functional customer orientation and adaptive selling behavior.

Figure 3 .
Figure 3.The moderating effect of emotional exhaustion on the relationship between relational customer orientation and adaptive selling behavior.

Figure 3 .
Figure 3.The moderating effect of emotional exhaustion on the relationship between relational customer orientation and adaptive selling behavior.

Table 1 .
Descriptive statistics analysis of control variables.

Table 2 .
Descriptive statistics and inter-correlations between variables.

Table 4 .
Discriminate validity of constructs.
Note: square root of AVE value is on the diagonal, and others are inter-correlations between constructs.
Note: FC refers to functional customer orientation, RC refers to relational customer orientation, EE refers to emotional exhaustion, and AS refers to adaptive selling behavior.

Table 6 .
Regression analysis of functional customer orientation and emotional exhaustion.

Table 7 .
Regression analysis of relational customer orientation and emotional exhaustion.

Table 7 .
Regression analysis of relational customer orientation and emotional exhaustion.