Extending the theory of planned behavior to predict organic food adoption behavior and perceived consumer longevity in subsistence markets: A post-peak COVID-19 perspective

Abstract

The goal of sustainable marketing remains mainstreaming consumer behavior change towards better and healthier products. This study examined the nexus between organic food adoption behavior and perceived consumer longevity in a post-peak COVID-19 period in Zimbabwe. The proposed model is grounded in the theory of planned behavior and the expectancy-disconfirmation paradigm. Organic food consumers in the upmarket suburbs in Harare were targeted. Using convenience sampling, a structured and person administered questionnaire, 256 valid responses were collected in a cross-sectional survey. Structural Equation Modelling in AMOS was used to analyse the survey data. The positive influence of green attitudes, subjective norms and perceived behavioral control on green adoption intentions was confirmed. Further, the results also revealed that green behavioral intentions positively affected organic food adoption behavior. The findings were also confirmatory of the positive impact of green adoption behavior on perceived consumer longevity (p < 0.05). The study concludes that green attitudes, subjective norms and perceived behavioral control significantly influence consumer intentions to adopt organic foods and their subsequent adoption behavior. More importantly, green adoption behavior has a significant impact on perceived consumer longevity in organic food markets. Therefore, to enhance long-term organic food consumption behavior, organic food marketers should leverage their embedded pro-health benefits that positively correlate with consumer perceptions of good health and longevity.

Keywords:

• COVID-19
• organic food adoption
• theory of planned behavior
• disconfirmation paradigm
• consumer longevity

1. Introduction

Global uncertainties have been widely observed, and sustainability debates have dominated the political, business and academic discussions in recent decades. Amid the global economic crisis, pandemic shocks, supply chain disruptions, food shortages, natural hazards, food-borne diseases and climate volatility (Hang et al., 2022; Lai & Cheng, 2016; Puri et al., 2020; Rahman et al., 2016), diverse sustainability initiatives have been envisaged. This connotes that human beings would experience extreme effects if no actions towards greener models are taken (Adnan & Nordin, 2021; Ha, 2021). Whilst overwhelming challenges have been evident globally, production and consumption of pro-health and environmentally friendly products has been widely recommended to contain climate problems and mitigate adverse health effects, hence humans have been identified as key drivers to sustainability (Alagarsamy et al., 2022; Bailey et al., 2016).

Organic foods are one category of green products that has been recommended as they help to preserve consumer health and maintain a cleaner and safer environment (Magnusson et al., 2003; Tarkiainen & Sundqvist, 2005). Whilst the parameters vary from country to country, organic food products must be manufactured using green or natural methods (Bonke & Musshoff, 2020). The popularity of food-borne diseases has also implored consumers to change their consumption habits towards healthier lifestyles (Matharu et al., 2022). However, consumer response to sustainability calls has been widely slow in most low-income countries (Chen, 2010; Ha, 2021). Problems with green trust, consumer phobias, green washing, perceived risk, and lack of universally agreed green standards have been reported in extant literature (Davari & Strutton, 2014; Ha, 2021; Polonsky, 1994). In Zimbabwe, green food adoption has been slow in mass consumer markets. However, considerable uptake has been observed in the upmarket segments endowed with advanced green literacy and more health-conscious consumers (Tschentscher & Diamond, 2012).

The outbreak of the COVID-19 pandemic meant that the global population was exposed to a high mortality risk (Dangaiso et al., 2023). The SARS-COV-2 virus was described as novel to connote its uniqueness to known viruses, hence its mitigation posed significant challenges (Dangaiso et al., 2023; Niculaescu, 2021). More so, the pandemic was worsened by consumer misinformation that triggered vaccine hesitancy in many regions (Puri et al., 2020). Subsequently, most consumers resorted to organic foods to strengthen their immune systems (Han & Hoang, 2020; Wagner et al., 2020). However, the flattening of the COVID-19 epidemic curve (Dangaiso et al., 2023) could signal future changes in consumption patterns of organic foods in especially developing countries like Zimbabwe, where adoption has been slower than anticipated. The purpose of this study was to evaluate organic food adoption behavior and consumer perceptions of its long-term impact on their physical health, welfare and improved life expectancy in Zimbabwe during the off-peak COVID-19 period.

The theory of planned behavior (Ajzen, 1991) has been widely employed to examine consumer behavior in green markets (Dilotsotlhe & Akbari, 2021; Matharu et al., 2022; Paul et al., 2016). Although its predictive validity has been confirmed in the extant consumer behavior literature, the theory does not account for post-adoption behaviors. Pursuant to Sustainable Development Goals (SDGs) (UnitedNations, 2015), sustainability has been envisaged to hinge on long-term usage of green methods and products (Ha, 2021). To that effect, this study modelled the effect of organic food adoption behavior on perceived consumer longevity as a proxy for predicting continued organic food consumption post the COVID-19 pandemic. Thus, in that view, disconfirmation of health benefits through organic food consumption forms the basis for either organic food consumption continuance or discontinuance post the initial adoption stage. It is on this key dimension that this research borrowed theoretical insights from expectancy-disconfirmation theory (Oliver, 1980).

This study brings important theoretical insights on the current applications and limitations of the theory of planned behavior and hence it highlights avenues for theoretical integration to explain post-adoption phenomena, especially in consumer markets. Moreover, the study brings a key impetus towards promotion of green consumption in pre-emerging markets such as Zimbabwe, where organic food consumption has not reached the desired landmarks. The findings from this study can be key for organic food marketers and public health professionals as they attempt to understand organic adoption and perceived health value from a consumer perspective in subsistence markets.

Public health policymakers, health professionals, community health-care providers and health-care marketers can use this research to expedite the development of effective marketing strategies for mainstreaming organic food consumption in subsistence markets. The recommendations of this research may also be relevant for organic food marketers in Zimbabwe as they envisage implementing effective targeting and positioning strategies for enhancing organic food uptake across heterogeneous market segments. The subsequent sections of this paper cover literature review, materials and methods, results and discussion, as well as conclusions, implications and recommendations of the study.

2. Literature review

2.1. Perceived consumer longevity

Concerted global sustainability efforts have been directed towards preserving the environment, improving consumer welfare and enhancing population life expectancy (Ha, 2021; Magnusson et al., 2003; Tarkiainen & Sundqvist, 2005). Consumer longevity remains the ultimate objective of green food adoption across consumer markets globally. Consumer health marketing initiatives have been intensively promoted with the goal of enlightening consumers towards subscribing to consumer longevity through responsible food consumption (Cong et al., 2020; Freivogel & Visschers, 2021).

This study is theoretically grounded in the theory of planned behavior (Ajzen, 1991) and the expectancy-disconfirmation paradigm (Oliver, 1980). Perceived consumer longevity is modelled as a key outcome of green adoption behavior and a springboard for mainstreaming long-term green consumption in subsistence markets. This paper defines perceived consumer longevity as the consumer’s perception of whether or not green adoption behavior positively impacts their physical health, quality of life and life expectancy. Perceived consumer longevity serves as a proxy for determining conscious consumer decisions on whether to continue consumption of organic foods or not based on perceived health value observed over cumulative organic food consumption behavior (Magnusson et al., 2003; Wagner et al., 2020).

2.2. Theoretical frameworks

2.2.1. Theory of planned behavior

The theory of planned behavior (Ajzen, 1991) explains that behavioral intentions to perform a behavior are influenced by underlying personal attitudes, subjective norms and perceived behavioral control they have over the behavior. The theory underpins cognitive-behavioral processes that influence whether they would like to adopt a certain behavior or not, based on the perceived outcome of the behavior (Ajzen, 1991). The theory of planned behavior was developed by Ajzen (1991) in an effort to improve the explanatory power of the theory of reasoned action.

According to the original theory, subjective norms and attitudes are key to the development of an intention to adopt a behavior (Ajzen & Fishbein, 1980). Behavioral intentions were predicted to positively influence behavior. A new construct, perceived behavioral control, was added to the framework, culminating in the theory of planned behavior (Ajzen, 1991). In a green context, it can be drawn from the theory that green adoption behavior may be influenced by green attitudes towards green products and subjective norms from reference groups (friends or family) as well as the consumer’s perception of their ability to control or manage green adoption.

Attitudes were defined as a pre-laid positive or negative individual disposition that explains their behavior towards a person or object (Schiffman & Kanuk, 1994). An attitude is defined as an internal orientation that explains an individual’s action (Ajzen, 1991). Attitudes have four underlying constructs that influence a person’s behavioral orientation; cognitive, affective, evaluative and conative (Schiffman & Kanuk, 1994). According to Ajzen and Fishbein (1980), individual attitudes towards an object, person or behavior primarily determine their positive or negative orientation towards that person, object or behavior. This implies that consumer’s green attitudes would positively or negatively affect their green adoption intentions.

Subjective norms were defined as an individual’s assessment of social acceptance or approval as a result of adoption of a new behavior (Ajzen & Fishbein, 1980). They refer to the unwritten rules that govern an individual’s behavior or new decisions (Baden & Prasad, 2016). For example, an individual’s assessment of whether a decision to consume organic foods would be accepted by their family or friends influences their intention to adopt organic foods. Subjective norms were identified as a key antecedent of behavioral intentions to perform a behavior, hence in an organic food context, consumers’ evaluation of social approval of organic food consumption would influence their intentions to adopt organic foods.

Perceived behavioral control was defined as the conviction by an individual of their ability to control, manage or cope up with the new behavior (Ajzen, 1991). This was predicted to influence whether an individual would be likely to adopt a new or recommended behavior or not. Applying theoretical lenses of the Health Belief Model (HBM) (Rosenstock, 2000) in health literature, perceived behavioral control mimics the role of self-efficacy in explaining adoption of a health action. Perceived behavioral control was predicted to affect a person’s adoption intention of a new behavior, thus in an organic food context, consumers evaluate their ability to cope up with the green adoption behavior, thus as a key predictor of organic food adoption intentions.

Behavioral intention was defined as a consciously formulated plan to adopt or change a certain behavior (Ajzen, 1991; Ajzen & Fishbein, 1980). Subjective norms, attitudes and perceived behavioral control were identified as the predictors of behavioral intention. Behavioral intentions represent an individual consensus on whether to perform or not a certain behavior (Ajzen, 1991). Behavioral intention was predicted to influence the performance of the actual behavior. Thus, in a green market context, green adoption intentions become a precondition for a consumer’s green adoption behavior.

2.2.2. The expectancy-disconfirmation theory

The expectancy-disconfirmation theory (Oliver, 1980, 1997) was developed in the field of consumer behavior. It attempts to explain the role of customer satisfaction on future behavioral intentions. The theory holds during the evaluation stage, consumers compare perceived performance and prior expectations that influence their future behavioral intentions. Positive disconfirmation occurs when perceived performance is greater than expectations, negative disconfirmation relates to perceived performance falling short of prior expectations and confirmation implies a state of equilibrium between expectations and performance. From the three scenarios, only negative disconfirmation causes customer dissatisfaction. Disconfirmation was proposed to influence customer satisfaction and this conditions their future behavioral intentions.

This paper borrows theoretical lens from the expectancy disconfirmation theory to propose that, within an organic food context, consumers evaluate their pre-adoption expectations against the perceived health performance of the organic foods. Thus, based on the theory, positive disconfirmation supports long-term organic food consumption behavior based on the perceived health value that consumers attach to such behavior. Conversely, negative disconfirmation leads to in a post adoption discontinuance arising from poor perceived health benefits from organic food consumption. Thus, in this context, perceived consumer longevity forms the basis for organic foods consumption continuance decisions based on disconfirmation of associated health values or benefits.

2.3. Development of hypotheses

2.3.1. Green attitudes and green adoption intentions

Individual attitudes have been cited as a strong antecedent of behavioral intention. Extant marketing literature cites a number of sources of attitude formation and this includes prior experience, reference groups, marketing communications and company image (Lee & Kotler, 2016; Schiffman & Kanuk, 1994). The tri-component model of attitude formation postulates that attitudes emerge with three core aspects, that is affective (emotional), behavioral (seen behaviors) and cognitive (mental processes) (Schiffman & Kanuk, 1994). A person’s attitude towards a person, object, product or brand influences their likeness or lack of it towards that particular entity (Ajzen, 1991). In the same vein, a consumer’s green attitude, whether positive or negative, influences their green adoption intentions.

Several studies have explored the effects of green attitudes on green adoption intentions in literature. Food safety attitude has been found to influence consumer food safety behavior by Solomon (2014) and Lim et al. (2016). Honkanen and Young (2015) also reported that attitude is a key antecedent of consumers buying seafood with British consumers. A study by Fotopoulos and Krystallis (2002) also found that consumer attitudes influenced Greek organic food consumers' intentions to purchase. Felix and Braunsberger (2016), Gupta and Ogden (2009) and Reisch and Thorgensen (2015) also observed that consumer attitudes significantly affected their purchase intentions of green foods. These findings were also confirmed in diverse consumer markets such as Purwanto et al. (2022), Umar et al. (2021), Dilotsotlhe and Akbari (2021), Suki (2016), Yadav and Pathak (2016) also confirmed that consumer attitudes towards green products are more apt to develop a stronger disposition to purchase a green product. As a result, the study hypothesized that;

H₁:

Green attitudes have a significant influence on green adoption intentions in organic food markets.

2.3.2. Subjective norms and green adoption intentions

Individual perceptions of the possibility of a reference group that agrees or disagrees or that approves or disapproves a certain behavior have an important effect on behavioral intentions (Purwanto et al., 2022). Social norms are unwritten rules of behavior regarding others’ views and attitudes towards a behavior (Baden & Prasad, 2016). Subjective norms have been observed to be a key influence on human behaviors in literature. According to the Ajzen (1991), people have a natural disposition for social likeness and approval and this conditions their decisions to approve or not certain actions or behaviors. In the same manner, consumers would evaluate the likelihood of their reference groups approving their organic consumption behaviors prior to adopting organic consumption behaviors, thus subjective norms can be proposed as an antecedent of green adoption intentions in organic food markets.

The effect of social influences on consumer behavioral intentions has been reported in a number of studies. According to Baber (2018), Baden and Prasad (2016) and Purwanto et al. (2022), surrounding social pressures influence consumer behavioral intentions. In their findings, they reported the significant effect of subjective norms on behavioral intentions. Hudi et al. (2019) and Ibrahim et al. (2017) also supported their claims. The significant impact of subjective norms on consumer behavioral intentions has also been reported in the studies of Mukarromah and Widana (2021), Umar et al. (2021), Maulana et al. (2018), Abdullahi et al. (2021), Ham et al. (2015) and Dilotsotlhe and Akbari (2021). Although Paul et al. (2016) reported the insignificant effect of subjective norms on green adoption intentions, there was sufficient empirical evidence to propose that;

H₂:

Subjective norms have a significant influence on green adoption intentions in organic food markets.

2.3.3. Perceived behavioral control and green adoption intentions

A person’s intention to adopt a certain behavior is subject to his or her evaluation of the ability to cope up or manage the likely consequences of the behavior (Ajzen, 1991; Rosenstock, 2000). Perceived behavioral control was an addition to the theory of reasoned action (Ajzen & Fishbein, 1980) in an effort to improve its predictive power. Other behavioral theories such as the Health Belief model (HBM) (Rosenstock, 2000) conceptualized it as perceived self-efficacy. In technology adoption literature, it was conceptualized as perceived ease of use (Davies, 1989). Across the theoretical perspectives, it implies that an individual’s belief that they are able to manage, contain or control the behavioral transition has a significant influence on their intentions to adopt the behavior. Consumers evaluate their perceptions of their ability to control or manage their green behaviors prior and this determines whether or not they will intend to adopt green foods (Paul et al., 2016).

Previous studies have shown that perceived behavioral control has a significant effect on behavioral intention. Within a microfinance context, Abdullahi et al. (2021), Kachkar and Djafri (2021), Maulana et al. (2018) and Purwanto et al. (2022) found that perceived behavioral control influenced consumers’ behavioral intentions. Similar findings have been observed in conservation (Albayrak et al., 2013), recycling (Yeow et al., 2014), green hotels (Chen & Tung, 2014), general green products (Moser, 2015), green appliances (Dilotsotlhe & Akbari, 2021) and organic foods (Paul et al., 2016; Tarkiainen & Sundqvist, 2005). Learning from these empirical findings, the study also predicted that;

H₃:

Perceived behavioral control significantly influences green behavioral intentions in organic food markets.

2.3.4. Green adoption intentions and green adoption behavior

Although green products such as organic foods offer significant eco-advantages and health appeals to those willing to make green a priority (Grant, 2008, p. 25), extant literature supports the view that a significant gap exists between green adoption intentions and actual green adoption behavior. This has been conceptualized by several researchers as the green dilemma (Muposhi et al., 2015), green rhetoric and green purchasing behavior gap (Johnstone & Tan, 2015), green beliefs-consumption behaviors gap (Davari & Strutton, 2014), green attitude-behavior gap (Peattie, 2010) and the purchase intentions-behaviors gap (Mendleson & Polonsky, 1995; Young et al., 2010). Most studies cite perceived risk (Chang & Chen, 2014), green mistrust (Ha, 2021) and most recently green washing (Akturan, 2018), alluding to green marketing firms’ positive communication about green performance and yet delivering poor environmental and health performance, as the main causes of this green intentions-green behavior standoff.

Notwithstanding the underwhelming transition from green intentions to green purchase, a positive correlation has been observed in other studies (Ha, 2021; Moser, 2015). Previous studies have demonstrated the importance of purchase intention on actual purchase behavior (Moser, 2015; Wang & Wang, 2017). Several studies have observed that green adoption intentions significantly influence green adoption behavior (Dilotsotlhe & Akbari, 2021; Lai & Cheng, 2016; Moser, 2015; Wang & Wang, 2017). These findings support the theoretical proposition by Ajzen (1991) that behavioral intentions significantly impact actual behavior. Against the foregoing discussion, the study hypothesized that;

H₄:

Green adoption intentions significantly influence green adoption behavior in organic food markets.

2.3.5. Green adoption behavior and perceived consumer longevity

Despite consumers seeking primary utility from the core functional attributes of the green foods they purchase, there is a consensus in literature that they purchase the green benefits (good health, cleaner environment and green fulfilment) embedded in these products (Alagarsamy et al., 2022; Magnusson et al., 2003; Rahman et al., 2016). This implies that any significant deviation from the pro-health and environmental promises has key consequences for the future purchases of green products (Alagarsamy et al., 2022; Wagner et al., 2020). Post-purchase evaluation should positively enhance future consumer behavioral intentions; thus, green dissonance undermines future usage behavior. More so, learning from the disconfirmation theory (Oliver, 1980), positive disconfirmation of organic foods performance is associated with consumer perceptions of good health, better welfare and longer lives. Thus, organic food adoption behavior should positively influence perceived consumer longevity if the green consumption is to reach sustainable levels (Magnusson et al., 2003).

Green scholars have projected positive outcomes of COVID-19 from a sustainability perspective. An increase in demand for organic foods has been observed as consumers sought to boost their immune systems using natural methods amid vaccine hesitancy in most regions (Alagarsamy et al., 2022; Guney & Sanguin, 2021; Puri et al., 2020). Demand for organic foods has been expected to remain even if the COVID-19 factors subside (Cong et al., 2020; Rana & Paul, 2020; Wagner et al., 2020). Past evidence confirms that demand for organic foods during pandemics was followed by sustained demand. Demand for organic meat surged after the Bovine Spongiform Encephalopathy crisis in 2000 in Europe, surge in demand for organic food after the SARS crisis in Asia in 2004 and demand for organic baby infant formula soared after the melamine scandal of 2008 in Asia (Alagarsamy et al., 2022).

The evidence suggests the significant effect of green adoption behavior on perceived consumer safety, good health and longer lives (Alagarsamy et al., 2022; Han & Hoang, 2020; Magnusson et al., 2003; Wagner et al., 2020). Thus, this study extends the theory of planned behavior with perceived consumer longevity based on disconfirmation of organic food benefits, proposing a direct positive influence of green adoption behavior on perceived consumer longevity. Perceived consumer longevity serves as a critical proxy for predicting long-term organic food consumption behavior. Therefore, the following hypothesis was proposed;

H₅:

Green adoption behavior significantly influences perceived consumer longevity in organic food markets.

Figure 1 illustrates the proposed research model.

Figure 1. Proposed research model.

Source: Modified from Ajzen (1991).

3. Materials and methods

3.1. Design, population and sampling

The purpose of the research was to examine the nexus between organic food adoption behavior and perceived consumer longevity. An explanatory design and a quantitative research approach were employed to examine structural relationships in a hypothesized model (Saunders et al., 2018). The study targeted adult (18 years and older) organic food consumers in the Harare suburbs of Avondale, Belgravia, Borrowdale, Chisipite, Glen Lorne and Mt Pleasant. In order to sample consumers who are knowledgeable and accessible to organic foods, these upmarket locations were purposely chosen. Consumers who had prior knowledge and consumption history of organic foods were sampled (Paul et al., 2016). The mall intercept method was used to conveniently select shoppers who filled and returned the questionnaires onsite. The study delivered 316, paper printed questionnaires with structured questions and 282 were returned, a response rate of 89.24%. After preliminary analyses, 256 valid responses were retained. Sample size determination was guided by sizes used in similar studies, data analysis methods, resource constraints and non-response considerations (Cohen, 1992; Hair et al., 2019; Saunders et al., 2018; Tabachnick & Fidell, 2013).

3.2. Measures

The measurement scales used in this study were adopted from extant literature (Table 2). Green attitudes (four items), subjective norms (three items), perceived behavioral control (four items), green adoption intentions (four items) and green adoption behavior (four items) were adopted from Dilotsotlhe and Akbari (2021) and Paul et al. (2016) whilst perceived consumer longevity (4 items) was adopted and modified from Magnusson et al. (2003). These were measured on a 7-point Likert scale, where 1 = strongly disagree, 2 = disagree, 3 = somewhat disagree, 4 = neutral, 5 = somewhat agree, 6 = agree and 7 = strongly agree. A pretest was conducted with 21 finalist marketing students from a local university in Harare. Apart from demographic items and research constructs, filter questions were used to screen out consumers who were not familiar with organic foods. Internal reliability using Cronbach's alpha was satisfactory for all constructs (>0.7) as shown in Table 2.

3.3. Data collection procedures and ethical compliance

In line with consumer research ethical guidelines, the purpose of the study was communicated and informed consent was sought. The participants were informed that participation was voluntary. Moreover, privacy and confidentiality were strictly observed during and post fieldwork. Further, participants were assured that there would be no harm or loss of integrity, personal property or any infringements as a result of the research. The instructions on the questionnaire also included that participants must not provide any personally identifiable information. Pursuant to safety, fieldwork was conducted off the heightened state of COVID-19. Further, precautionary counter measures employed in related studies, for example, Dangaiso et al. (2023 a), Dangaiso et al. (2023 b) and Shitu et al. (2022) such as wearing gloves and facemasks, using hand sanitisers, keeping social distance and practicing good hygiene were adopted.

3.4. Data analysis methods

Confirmatory Factor Analysis (CFA) and Structural Equation Modelling (SEM) were employed to assess the research model (Anderson & Gerbin, 1988). Confirmatory Factor Analysis assessed the measurement model whilst Structural Equation Modelling was used to examine a priori hypothesized structural relationships in the proposed research model. The absolute fit indices used were Chi Square (CMIN/x²), normed Chi Square (x²/df), Root Mean Square Error of Approximation (RMSEA), Standardised Root Mean Residual (SRMR) and the Goodness-of-Fit Index (GFI). The relative and incremental fit indices that were employed were the Incremental Fit Index (IFI), Comparative Fit Index (CFI), Tucker-Lewis Index (TLI) and the Normed Fit Index (NFI). Convergent validity was assessed using the Average Variance Extracted (AVE) (Hair et al., 2019) whilst the comparison between the square roots of the Average Variance Extracted and construct correlations determined discriminant validity (Fornell & Larcker, 1981; Hair et al., 2019). Construct reliability was examined using composite reliability and Cronbach’s alpha (Hair et al., 2019; Kline, 2023).

4. Results

4.1. Sample characterisation

The socio-demographic characteristics of the sample that was used in this study were analysed. Table 1 shows the socio-demographic properties of the participants (n = 256).

Table 1. Sample profile

Variable	Category	Frequency	Percentage
Gender	Male	126	49.2
	Female	130	50.8
Age	18–25 years	30	11.7
	26–33 years	42	16.4
	34–41 years	44	17.2
	42–49 years	51	19.9
	50–57 years	58	22.7
	58–65 years	31	12.1
Education	Ordinary level	9	3.5
	Professional diploma	40	15.6
	Honors degree	132	51.5
	Master’s degree	47	18.4
	Doctorate degree	28	10.9
Monthly income	$1–500	42	16.4
	$501–1000	71	27.7
	$1001–1500	63	24.6
	$1501–2000	51	19.9
	Above $2000	29	11.3

4.2. Assessment of the measurement model

Using maximum likelihood estimation, unidimensionality of the factor loadings was verified and all observed variables produced good loadings except item GA4 on green attitudes (0.468). Based on Kline (2023), loadings of at least 0.7 are recommended and GA4 was subsequently removed. Retained standardised loadings ranged from 0.743 (PCL1) to 0.952 (PCL4), both on perceived consumer longevity (Table 2). All t-values (+12.700 to + 22.009, p < 0.001) were adjudged to be significantly different from zero. The squared multiple correlations were also above 0.5 (Hair et al., 2019) (Table 2).

Table 2. Psychometric properties of the measurement model

Construct/Observed	Loading	SMC	AVE	MSV	CR	CA
Green Attitudes			0.705	0.619	0.877	0.872
GA1: I prefer/like purchasing organic to non-organic food products.	0.859***	0.738
GA2: I consider organic food purchase important.	0.876***	0.768
GA3: Consuming organic food is good for my health.	0.780***	0.609
Subjective Norms			0.715	0.680	0.883	0.881
SN1: Purchasing organic food causes me to be admired.	0.826***	0.682
SN2: Most people who are important to me expect that I should buy organic food.	0.873***	0.761
SN3: Purchasing the organic food improves the way I am perceived.	0.837***	0.701
Perceived Behavioral Control			0.695	0.680	0.901	0.900
PBC1: I believe that I have the financial ability to purchase organic food.	0.860***	0.739
PBC2: I see myself as capable of purchasing organic food in future.	0.866***	0.750
PBC3: I see myself as capable of using organic food in future.	0.837***	0.701
PBC4: Organic foods are generally available in the shops where I usually do my shopping.	0.767***	0.588
Green Adoption Intentions			0.676	0.474	0.893	0.902
GAI1: I intend to buy organic food because of its pro-health benefits.	0.817***	0.667
GAI2: I definitely want to purchase organic food brands in my next purchase.	0.828***	0.686
GAI3: I expect to continue to purchasing organic food in the future because of its positive health contribution.	0.834***	0.695
GAI4: I will always consider using to organic food for my pro-health reasons.	0.810***	0.656
Green Adoption Behavior			0.720	0.383	0.911	0.909
GAB1: I make a special effort to buy organic food.	0.826***	0.683
GAB2: I have switched to buying organic food because of its the health benefits.	0.878***	0.771
GAB3: I make a special effort to buy food products that are green, pro-health or environmentally friendly.	0.855***	0.732
GAB4: Given a choice between the same types of food products, I purchase the ones that green or organic in nature.	0.835***	0.696
Perceived Consumer Longevity			0.741	0.383	0.919	0.922
PCL1: I believe that organic food consumption strengthens my immune system.	0.743***	0.552
PCL2: I am certain that organic food will protect me from diseases for many years to come.	0.864***	0.746
PCL3: Choosing organic food has been one of my best decisions as far as my long-term health is concerned.	0.872***	0.760
PCL4: Organic food consumption will certainly improve my life expectancy.	0.952***	0.907

Notes: AVE = Average Variance Extracted; Loading = Standardised factor loading; SMC = Squared Multiple Correlations; MSV = Maximum Shared Variance; CR = Composite Reliability; CA = Cronbach Alpha; loadings marked with three asterisks (***) denotes p<0.001.

The lowest Average Variance Extracted (AVE) was 0.676 on green adoption intentions whilst the highest was 0.741 on perceived consumer longevity (Table 2). According to Hair et al. (2019), the AVE should be at least 0.5 to confirm convergent validity, thus convergent validity was present. Table 3 shows that the square roots of AVEs are above the corresponding construct correlations to confirm discriminant validity (Fornell & Larcker, 1981). More so, the Maximum Shared Variance (MSV) scores were below the AVE scores (Table 2), this confirms that the constructs had discriminant validity (Hair et al., 2019). As shown in Table 2, construct reliability was examined with composite reliability ranging from 0.77 (green attitudes) to 0.919 (perceived consumer longevity). The Cronbach's alpha values also ranged from 0.872 (green attitudes) to 0.922 (perceived consumer longevity). According to Nunnally and Bernstein (1994), these should be at least 0.7, thus internal reliability is satisfied (Table 2).

Table 3. Assessment of discriminant validity

Construct	1	2	3	4	5	6
Green attitudes (1)	0.839
Subjective norms (2)	0.787	0.883
Perceived behavioral control (3)	0.752	0.825	0.833
Green adoption intention (4)	0.663	0.689	0.659	0.822
Green adoption behavior (5)	0.592	0.537	0.487	0.535	0.849
Perceived consumer longevity (6)	0.451	0.403	0.397	0.424	0.619	0.861

Notes: Square roots of Average Variance Extracted are bolded on the diagonal; construct correlations are below the diagonal.

The initial measurement model had a good fit (CMIN/x² = 456.45, df = 194, x²/df = 2.353; SRMR = 0.037; RMSEA = 0.073; GFI = 0.855; CFI = 0.943; TLI = 0.932; NFI = 0.920; IFI = 0.943). However, modification indices suggest covariances between error terms to reduce the discrepancy between the sample variance-covariance matrix and the variance-covariance matrix of the hypothesized model. Error terms between items belonging to the same parent latent construct were allowed to covary (Byrne, 2013; Kline, 2023). The re-specification improved the model fit (CMIN/x² = 359.43, df = 188, x²/df = 1.912; SRMR = 0.036; RMSEA = 0.060; GFI = 0.888; CFI = 0.963; TLI = 0.954; NFI = 0.925; IFI = 0.963). Using thresholds recommended by Anderson and Gerbin (1988), Byrne (2013), Hu and Bentler (1999) and Kline (2023), the measurement model had a very good fit.

4.3. Assessment of the structural model

Prior to estimating the causal structural relationships, the fit between the hypothesized model and sample data was examined. A very good model fit was observed for the structural model (CMIN/x² = 390.31, df = 195, x²/df = 2.002; SRMR = 0.065; RMSEA = 0.063; GFI = 0.879; CFI = 0.957; TLI = 0.950; NFI = 0.919; IFI = 0.958). Based on the thresholds established by Byrne (2013), Hu and Bentler (1999) and Kline (2023), the structural model obtained a very good fit.

Secondly, the model was examined based on the significance of the estimates on their hypothesized paths. Hypothesis H₁ had hypothesized the effect of green attitudes on green adoption intentions. The causal path confirmed the relationship (β = 0.337, t = 5.135, p = 0.01). H₂ had proposed that subjective norms influence green adoption intentions. The results confirmed this influence in the model (β = 0.311, t = 4.967, p = 0.01). In the third, the study had also hypothesized the effects of perceived behavioral control on green adoption intention (H₁). The results supported this relationship (β = 0.154, t = 2.465, p = 0.04). As a result, H₁, H₂ and H₃ gained empirical support and were subsequently accepted. The results were confirmatory of the role played by green attitudes, subjective norms and perceived behavioral control in determining an individual’s intention to adopt organic foods.

Furthermore, the study also predicted that green adoption intentions positively affect green adoption behavior (H₄). The results of structural equation modelling confirmed this effect (β = 0.588, t = 9.921, p < 0.001). Finally, the paper had also modelled the positive effect of green adoption behavior on perceived consumer longevity (H₅). The results supported this relationship (β = 0.625, t = 9.563, p < 0.001). Consequently, H₄ and H₅ were supported. The results confirm that green adoption will lead to green adoption behavior. The findings also support the idea that organic food adoption behavior positively drives consumer perceptions of physical wellness, good health and longer lives. Figure 2 illustrates the structural model and Table 4 shows the results of hypothesis testing.

Figure 2. The structural model.

Notes: Per = Perceived; Gr = Green; Consu = Consumer

Table 4. Results of hypothesis testing

Hypothesis	Estimate	Standardised Estimate	S.E	C.R	p-value	Result
H1: GA➔GAI	0.351	0.337	0.059	+5.949	0.01	Supported
H2: SN➔GAI	0.303	0.311	0.061	+4.967	0.01	Supported
H3: PBC➔GAI	0.143	0.154	0.058	+2.465	0.04	Supported
H4: GAI➔GAB	0.635	0.588	0.064	+9.921	***	Supported
H5:GAB➔PCL	0.526	0.625	0.055	+9.563	***	Supported

Notes: GA = Green Attitudes; SN = Subjective Norms; PBC = Perceived Behavioral Control; GAI = Green Adoption Intentions; GAB = Green Adoption Behavior; PCL = Perceived Consumer Longevity; Estimate = unstandardized estimate; S.E = Standard Error; C.R = Critical Ratio/t-statistic; *** denotes p<0.001.

5. Discussion

The study extended the theory of planned behavior to predict organic food adoption behavior and consumer perceptions of longer and healthier lives. Hypothesis H₁ had proposed the effect of green attitudes on intention to adopt organic foods. This hypothesis was supported (β = 0.337, t = 5.135, p = 0.01). Our findings support the Ajzen (1991) in that attitude is an important predictor of behavioral intention, and thus a positive attitude towards organic foods will stimulate organic purchase and usage intentions. Green attitudes were also the strongest predictor of intention to adopt organic foods. Questions asked to respondents, for example, “I consider organic food purchase important,” (t = 17.355, p < 0.001) and “I prefer/like purchasing organic to non-organic food products,” (t = 14.667, p < 0.001) indicate that consumer attitudes are important to induce organic food purchase intention. Thus, organic food marketers should target the formation of positive attitudes by communicating a strong health value proposition to skeptical consumer segments in Zimbabwe. Current findings support Dilotsotlhe and Akbari (2021), Fotopoulos and Krystallis (2002), Honkanen and Young (2015) and Solomon (2014).

In H₂, the study had predicted the effect of subjective norms on green adoption intentions in an organic food context. The findings of the study provided sufficient evidence to support this hypothesis (β = 0.311, t = 4.967, p = 0.01). In line with the propositions by the Ajzen (1991), the results suggest that perceived social pressure from other consumers influences an individual’s intention to adopt organic foods. Observed variables, for example, “Purchasing the organic food improves the way I am perceived,” (t = 17.105, p < 0.001) suggest that peer validation or social approval has a key bearing on acceptance and intention to consume organic foods. Given this, health-care professionals and organic food marketers should craft advertising content that stimulate group affiliations towards organic foods. These findings do not present a new phenomenon in green adoption literature as Baber (2018), Ham et al. (2015), Maulana et al. (2018), Purwanto et al. (2022) and Umar et al. (2021) reported similar findings. However, Paul et al. (2016) reported the insignificant effect of subjective norms on green adoption intentions with organic foods.

The study also predicted that perceived behavioral control would influence green adoption intentions in H₃. The results of the study were confirmatory of this relationship (β = 0.154, t = 2.465, p = 0.04) and H₃ gained empirical support. The findings support the Ajzen (1991), as it was revealed that consumers evaluate the ease of managing their organic food usage routines prior to adoption. This research reveals that if consumers feel that they can adopt organic foods without challenges, they intend to adopt organic foods. Questions asked, for example, “I believe that I have the financial ability to purchase organic food,” (t = 17.706, p < 0.001) and “Organic foods are generally available in the shops where I usually do my shopping,” (t = 14.143, p < 0.001) affirm the significance of consumer self-efficacy before choosing to adopt organic foods. It is imperative that to improve the uptake of organic foods in Zimbabwe, organic food marketers should educate and instill consumer confidence that using organic foods is easy, good for health and are affordable and conveniently accessible. Our findings support Chen and Tung (2014), Dilotsotlhe and Akbari (2021), Moser (2015) and Paul et al. (2016). Altogether, green attitudes, subjective norms and perceived behavioral control accounted for 56.2% of the variability in green adoption intentions.

The study also proposed that green adoption intentions positively influence green adoption behavior in an organic food context. Although debates on the transition between green intentions and actual behavior have dominated the extant green consumption literature (Davari & Strutton, 2014; Johnstone & Tan, 2015; Muposhi et al., 2015; Peattie, 2010), the findings of this study support Ajzen (1991) (β = 0.588, t = 9.921, p < 0.001). Acceptance of H₄ encapsulates that the positive impact of green adoption intentions on adoption behavior was confirmed. Observed variables, for example, “I intend to buy organic food because of its pro-health benefits,” (t = 12.700, p < 0.001) and “I will always consider using to organic food for my pro-health reasons,” (t = 16.247, p < 0.001) suggest that green behavioral intentions precede the subsequent adoption behavior. Green adoption intentions explained 34.6% of the variability in green adoption behavior. These results have been confirmed in prior research (Dilotsotlhe & Akbari, 2021; Lai & Cheng, 2016; Moser, 2015; Wang & Wang, 2017).

The ultimate hypothesis (H₅) predicts that green adoption behavior would positively influence perceived consumer longevity. Green consumption has been premised on expediting the adoption of foods that provide anti-oxidants, vitamins and other natural properties that strengthen human immune systems (Han & Hoang, 2020; Wagner et al., 2020). The results of the study support the proposition that with successive consumption of organic foods, consumer perceptions of longer and healthier lives also positively improved. Thus, there was sufficient evidence of positive disconfirmation of organic foods’ health performance (β = 0.625, t = 9.563, p < 0.001), hence, H₅ was supported.

Observed variables, such as “I have switched to buying organic food because of its the health benefits,” (t = 15.750, p < 0.001) indicate that consumers use organic food seeking health benefits. Further, “Choosing organic food has been one of my best decisions as far as my long-term health is concerned,” (t = 22.009, p < 0.001) also indicates that there are strong perceptions of long-term health aligned with organic food consumption behavior. Green adoption behavior explained 39% of the variance in perceived consumer longevity. The findings suggest significant long-term organic food consumption prospects in Zimbabwe post the COVID-19 pandemic. However, extensive marketing is still needed so that organic foods appeal to the wider mass market. The results lean to those by Alagarsamy et al. (2022), Guney and Sanguin (2021), Magnusson et al. (2003) and Wagner et al. (2020). This finding presents a key dimension of the contributions of this study, given that the novelty of the research was situated on the proposed causal link between organic food adoption behavior and perceived consumer longevity in Zimbabwe.

6. Conclusions, implications and recommendations

6.1. Conclusions

The study examined the nexus between organic food adoption behavior and perceived consumer longevity in Zimbabwe. This paper makes important contributions towards advancing theory and practice in consumer behavior and health marketing. The proposed research model grounded in the theory of planned behavior and the expectancy-disconfirmation theory was empirically validated. The paper concludes the key positive roles played by green attitudes, subjective norms and perceived behavioral control on green adoption intentions and subsequently green adoption behavior. More importantly, the study received positive empirical confirmation on the proposed causal effect of green adoption behavior on perceived consumer longevity in an organic food context. Therefore, to enhance sustainable organic food adoption, green marketers should leverage their embedded pro-health value that positively correlates with consumer perceptions of good health and longevity.

6.2. Theoretical implications

This study brings important theoretical and practical implications. This paper validates and extends the theory of planned behavior (R square = 56.2% for green adoption intentions and 34.6% for green adoption behavior) with perceived consumer longevity (R square = 39%), based on the disconfirmation of health benefits in an organic context in a subsistence economy. This study can provide important theoretical insights on the current applications and limitations of the theory of planned behavior (Ajzen, 1991). To the best of the author's knowledge, this study becomes the first to model the effects of organic food adoption behavior on consumer perceptions of longevity. Furthermore, the study demonstrates an extension of the framework using insights from the disconfirmation paradigm to account for post-adoption behaviors that are important in consumer markets and how they can be harnessed to promote sustainable green consumption. Therefore, this study can provide a baseline on which future researchers may integrate the underlying theoretical framework with other models that attempt to explain consumer behavior within their peculiar contexts, enhancing the explanatory power of the framework.

6.3. Practical implications and recommendations

The research brings a key impetus for organic food uptake and a springboard for consumer health consciousness in sub-Saharan developing economies, amid concerted efforts to mitigate population mortality and enhance consumer longevity. Given that organic food uptake is yet to reach the desired landmarks in developing countries like Zimbabwe, this study lends key insights to organic food producers and marketers on developing and communicating key health propositions that promote adoption. In this regard, perceived consumer longevity with organic food consumption serves as a proxy for determining organic food consumption continuance, a significant lever on population health given the exponentially rising health-care costs and financial constraints in developing countries.

The study can inform health authorities, health educators, health promoters, community assistants and related stakeholders on the key theoretical aspects that explain consumer health behaviors. The study can aid various health stakeholders in devising effective health promotion programmes that are designed to change negative behaviors which have adverse health effects. This study has the potential to educate consumers on overcoming underlying cognitive, internal and social variables that unconsciously determine their key behaviors hence they can improve their self-efficacy needed to enhance their routine choices from the viewpoint of an educated consumer.

The study pinpoints the need to effectively leverage organic food marketing based on its unique health value proposition. This means that organic food marketers should devise compelling direct marketing strategies that target positively influencing individual green attitudes to enhance organic food adoption behavior. Furthermore, green food marketers should also target social groupings or design messages that have stimulated positive group thinking such that subjective norms do reinforce organic food adoption. More so, organic food marketers should improve consumer education, thus targeting better consumer self-efficacy, which enhances behavioral intentions to adopt green foods. Perceived behavioral control supported intentions to adopt organic foods.

Green marketers should also facilitate the transition from green intentions to green behavior through green fulfillment (green satisfaction). The challenge with most green products has been lower or no health and environmental fulfilment than they promise (green washing) (Ha, 2021; Polonsky, 1994). Green satisfaction with organic food consumption positively influences perceived consumer longevity associated with organic foods and thus long-term health preservation prospects are enhanced, reducing health-care costs and population mortality in subsistence economies.

6.4. Limitations and future study directions

Although the study accomplished its objective, it was not exempt from inherent research limitations. The study drew its sample from an upmarket urban cohort of more health-conscious consumers and this presents a limitation on the generalisability of research findings. Further, the socio-demographic traits of the participants indicate that at least 51.5% had university education. This also presents a limitation on the generalizability of findings across consumer groups with more heterogeneous literacy characteristics. A more representative sample from a diverse target population may be drawn in the future research. A limitation on the research model is also provided. Although the research extended the theory of planned behavior with perceived consumer longevity based on “theoretical insights” from the expectancy disconfirmation theory, the “actual constructs” of the framework were not completely integrated. This presents a limitation and research avenues which future studies may explore. Finally, a limitation on the mono quantitative approach used is presented. Future studies may adopt mixed methods so that research findings can be validated from diverse perspectives.

Open scholarship

This article has earned the Center for Open Science badges for Open Data, Open Materials and Preregistered. The data and materials are openly accessible at https://doi.org/10.7910/DVN/E0OA7Z

Acknowledgements

The authors would like to thank all the participants who took part in the survey.

Disclosure statement

No potential conflict of interest was reported by the author.

Data availability statement

Data used in this survey will be availed by the author on a reasonable request.

Additional information

Funding

The author has no direct funding to report

Notes on contributors

Phillip Dangaiso

Phillip Dangaiso is a full-time lecturer at the Zimbabwe Ezekiel Guti University (ZEGU). A multi-award winner, this research is one of his authored works. He has publications in high impact journals advancing Public Health Promotion, Social Marketing, Green Marketing, Digital Transformation in Higher Education and Management of Servicescapes.