Simplicity Matters: Unraveling the Impact of Minimalist Packaging on Green Trust in Daily Consumer Goods

Abstract

This study delves into the complex dynamics of consumer attitudes toward sustainable products, particularly within the fast-moving consumer goods category, highlighting the significant correlation between elegant and minimalist design aesthetics and the establishment of green trust in sustainable product offerings. Interestingly, while visually complex packaging may capture visual attention, it does not generate higher levels of green trust compared to simpler alternatives within the same product category. The findings underscore the importance of simple packaging design in mitigating consumer skepticism toward manipulative intentions and enhancing trust in sustainable products. Furthermore, this research reveals that individuals with higher levels of expertise possess deeper insights in perceiving complexity as a potential form of manipulation, thereby exacerbating skepticism toward sustainable products. In summary, the research outcomes guide sustainable product packaging design, emphasizing alternative solutions to convoluted designs that may lead to confusion. The effectiveness of simple design expression in sustainable products is emphasized, fostering the transition toward sustainable business efficacy and long-term development.

1. Introduction

Sustainable development is widely acknowledged as a paramount paradigm for integrating economic, social, and environmental imperatives [1]. The daily consumption sector plays a pivotal role in the pursuit of sustainable development. While the environmental benefits of individual products may seem modest, the cumulative environmental impact of widely adopted sustainable consumer goods cannot be underestimated. However, despite consumers’ professed heightened consciousness and acumen regarding environmental sustainability, their propensity to translate such awareness into tangible actions through the purchase of sustainable products remains limited [2,3,4,5]. Research indicates that the presence of “information asymmetry” surrounding sustainable products impedes the transformation of consumer interest into actual sustainable behaviors. This information asymmetry manifests across various dimensions, encompassing consumer skepticism toward environmental concerns, doubts regarding the veracity of environmental claims made by manufacturers, and uncertainties pertaining to the environmental benefits conferred by sustainable products [6,7]. Furthermore, consumers exhibit a reluctance to invest additional time and cognitive effort in discerning and selecting sustainable products, particularly within the realm of fast-moving consumer goods [8]. Consequently, relative to indirect informational cues, the direct conveyance of information through the visual stimuli of product packaging assumes heightened significance [9,10]. Research posits that consumers gauge the credibility of sustainable products based on packaging elements such as brand associations and eco-labels [11,12,13]. Moreover, beyond the dissemination of valuable information, product packaging often serves as a visual enticement, employing a plethora of captivating patterns, images, and color schemes to captivate consumers’ attention [14]. Nonetheless, while captivating visual attention may heighten product exposure, its efficacy in cultivating positive attitudes and trust toward sustainable products remains elusive [15]. “Eco-friendliness” emerges as an archetypal attribute of sustainable products, and the credibility of their ecological attributes critically underpins the conversion of investments into returns, thereby exerting a cascading effect on subsequent sustainable behaviors undertaken by businesses [16]. Hence, this study directs its focus toward the interplay between “green trust” and “attention-grabbing” within the realm of sustainable product packaging. Specifically, this study examines which packaging approach (elaborate vs. minimalist) is more efficacious in capturing consumers’ attention, fostering trust, and stimulating purchase intentions for sustainable products featuring environmental claims.

To investigate the aforementioned issues, this study employed a comprehensive approach that integrates eye-tracking experiments across multiple product categories with scenario-based experiments to elucidate the role of complexity in the packaging of daily sustainable products. Firstly, this study unveiled the inherent contradiction between “visual attention” and “trust” in sustainable products. While meticulously designed embellishments can captivate consumer attention, they can also undermine individuals’ trust in the product’s sustainability. Further investigation indicates that this contradiction is linked to the manipulative intentions conveyed by intricate decorative patterns, thereby eroding consumer trust. Moreover, this article explores the boundary conditions of this effect and underscores its significance under high empirical circumstances. The primary contributions of this article are as follows: Firstly, by enriching the theory of visual simplicity, a novel research perspective is provided for the contentious conclusions regarding simple and complex designs in the realm of daily sustainable products. Secondly, this article broadens the research scope of green trust by integrating visual elements in daily sustainable products with trust-related concerns and presents an explanatory mechanism from the vantage point of operational reasoning.

2. Hypotheses Development

2.1. Visual Attention and Green Trust under Packaging Complexity

Packaging complexity serves as a manifestation of the irregularity, distinctiveness, and intricacy of visual elements, as well as the abundance of patterns or objects, or their intricate arrangements, within the packaging framework [17]. Research posits that while simplistic designs activate ingrained object and pattern perception, more elaborate designs possess greater allure, reflecting the inherent adhesive nature of images [18,19]. Additionally, scholarly inquiries highlight the association between complexity and the captivation of visual attention, enthralling gazes, engendering consumer perceptual curiosity, and stimulating exploratory behaviors [20,21]. However, this captivation of attention may reveal underlying intentions of temptation and manipulation aimed at influencing the reception of targeted information [22,23]. Investigations into the perception of brand personality induced by packaging complexity reveal that minimalist designs readily evoke associations with reliability and elevated brand image quality [24]. From the vantage point of brand personality, streamlined designs fashion a dependable brand image, thereby fostering heightened levels of consumer trust in the realm of sustainable marketing. Moreover, cognitive fluency emerges as a pivotal factor in the sphere of complexity’s influence [25,26]. Certain scholars have melded cognitive fluency with the concept of trust. Research indicates that the veracity of statements encompasses a quality of remote stimuli that eludes direct observation or firsthand experience, necessitating inference derived from proximal cues. Among these cues, an individual’s perception of fluency emerges as an influential component, intertwining with positive and gratifying cognitive encounters, ultimately fostering trust [27]. Consequently, the simplification of sustainable product packaging design contributes to the formation of positive proximal cues, thereby fostering a favorable disposition toward sustainable product trust.

Therefore, the following hypotheses are proposed:

H1. 

Compared to intricate embellishments, simplistic adornments will diminish consumers’ visual attention.

H2. 

In contrast to complex packaging, simple, sustainable product packaging will enhance consumers’ trust in sustainable products.

2.2. Mediating Role of Manipulation Inference

The study of manipulation inference is grounded in the persuasion knowledge model (PKM), which delves into the realm of consumer psychology. According to PKM, consumers possess a dynamic knowledge structure concerning persuasion and utilize it to infer the intentions of others who seek to influence them. This persuasion knowledge comprises consumers’ beliefs about persuasive tactics, encompassing speculations about marketers’ motives, the strategies they employ to achieve their objectives, and the psychological mechanisms through which these strategies impact consumers’ attention, interest, and emotional responses [28]. PKM posits that marketers’ actions activate consumers’ persuasion knowledge, leading them to become cognizant and skeptical of the marketers’ intentions, ultimately inferring that these persuaders may be untrustworthy and seeking to manipulate their decision-making processes. Consequently, this inference breeds a sense of distrust in the persuaders. In the context of product packaging, complexity is often characterized by ornate embellishments that prioritize aesthetics over functionality, with the underlying motive of captivating and manipulating consumers [29]. As market economies progress, consumers have become increasingly aware that profit-driven companies may resort to unethical means to promote their products [30]. Consequently, consumers have become wary of excessively adorned products, as they perceive these embellishments to serve the purpose of influencing consumer behavior rather than providing genuine functional benefits. And once aware of the process of persuasion, people show resistance [31]. Drawing from the persuasion knowledge model, this manipulative intent triggers consumers’ vigilance, leading them to believe that the decorative elements of the product serve as a veil to conceal potential deficiencies in its sustainable performance, resulting in a diminished positive evaluation.

Therefore, the following hypothesis is proposed:

H3. 

Manipulation inference mediates the influence of packaging complexity on green trust. Specifically, compared to complex packaging, simple, sustainable product packaging reduces consumers’ propensity to infer manipulation, thereby enhancing their trust in sustainable products.

2.3. Moderating Role of Expertise Level

Consumers with varying levels of expertise possess distinct consumer knowledge and cognitive capabilities [32]. In the context of this study, expertise level reflects consumers’ depth of understanding and discernment regarding sustainable products. Research indicates that cognitive needs are closely linked to cognitive activities, whereby consumers with higher expertise levels exhibit greater product involvement and engage in more extensive cognitive processing, displaying a propensity for profound contemplation and decision-making activities [33]. Conversely, when the association between individuals and cognitive tasks is low, their information processing tends to be simple, devoid of in-depth and meticulous thought processes [34]. Given the ubiquity of fast-moving consumer goods in everyday life, most individuals pay little attention to their immediate perceptions of products. The persuasion knowledge model posits that the degree to which consumers’ persuasion knowledge is activated hinges on the salience of marketers’ manipulative intent. When such intent is inconspicuous, participants adopt a positive stance. However, when manipulative intent is conspicuous, participants activate their persuasion knowledge, resulting in negative evaluations of the target [35]. Consumers with higher levels of expertise possess heightened cognitive demands, leading them to approach product information with greater circumspection. Consumers endowed with a heightened level of expertise exhibit elevated cognitive exigencies, thereby approaching product communication with greater discernment. Consequently, such heightened expertise predisposes these consumers to interpret sustainable packaging complexity as a manipulative endeavor, prompting introspection into the marketer’s underlying motives encapsulated within the product design and engendering a heightened state of persuasion consciousness, ultimately culminating in unfavorable appraisals. Moreover, the augmented level of specialization also confers upon these consumers an enhanced sense of autonomy, rendering them more resistant to behaviors that encroach upon their individualistic decision-making prerogatives [36]. This will lead them to display a heightened level of mistrust toward potential manipulative behaviors in the context of sustainability.

Therefore, the following hypotheses are proposed:

H4. 

Expertise level moderates the impact of packaging complexity on the inference of manipulation. Specifically, consumers with higher expertise levels are more likely to interpret complexity as manipulative intent in sustainable products compared to those with lower expertise levels.

H5. 

Expertise level moderates the impact of manipulation inference on green trust. Specifically, consumers with higher expertise levels are more susceptible to diminished trust due to the inference of manipulative intent compared to those with lower expertise levels.

Grounded in the scholarly evidence uncovered during the literature review, we have developed a conceptual model of hypotheses (Figure 1) to examine the underlying mechanisms linking the intricacy of packaging design with the establishment of green trust.

3. Methodology

This article conducted three experiments, including one eye-tracking experiment and two scenario experiments. Experiment 1 combined eye-tracking and questionnaire methods to investigate the impact of packaging complexity on green trust. Experiment 2 aimed to replicate the main effect and explore the mediating role of manipulation inference. Experiment 3 aimed to replicate the main effect and mediating effect while exploring the mediating role of expertise level. It also included the investigation of the downstream variable, purchase intention.

3.1. Experiment 1: Visual Attention and Green Trust under Different Complexity Packaging

Experiment 1 utilizes a within-subject design to meticulously examine the association between visual complexity and green trust through the integration of eye-tracking experiments and subjective scales. Eye-tracking experiments serve as a valuable tool for unveiling consumers’ visual attention patterns within diverse packaging environments, thereby offering initial insights into potential underlying mechanisms.

3.1.1. Participants

According to Gpower 3.1, with a significance level (α) of 0.05 and a medium effect size, a minimum total sample size of 34 participants is required to achieve a statistical power of 80%. Due to accessibility constraints, a total of 36 participants from a single university took part in the experiment. The participants’ ages ranged from 20 to 27 years (M = 23.25, SD = 1.688). Among them, 15 are males and 19 are females. A total of 22 people hold a bachelor’s degree, and 14 people hold a graduate degree. To eliminate potential confounding factors affecting visual responses, all participants were right-handed and had normal or corrected-to-normal vision without color blindness or color weakness. They received a certain incentive for participating in the experiment.

3.1.2. Procedures

This experiment used a Tobii Pro eye tracker to collect data. Before the experiment began, participants underwent a review of the experimental procedure, received guidance, and provided informed consent forms and basic demographic information. Subsequently, participants were asked to imagine themselves planning to purchase laundry detergent, only to encounter two different packaging of laundry detergent on store shelves. Before the experiment begins, a 5-point calibration procedure will be performed to calibrate the fixation points of the participants. Afterward, participants were asked to initially focus their attention on the “+” symbol at the center of the screen. Afterwards, stimulating materials were provided to the participants.

According to the research objective of promoting sustainable green consumption behavior, the experimental material selected for this study is a common daily product—laundry detergent. To control the influence of brand factors on the experimental results, a virtual brand named “Nature” was created in the experiment. Based on previous principles, the complexity of packaging was manipulated by changing the number of decorative elements and their symmetry [37]. As shown in Figure 2, the complexity of the stimulus material increases from left to right. It is worth noting that although the packaging complexity varies, the promotional content of all experimental materials is consistent.

In addition, to simulate a realistic consumer environment where simple and complex products are presented side by side and to examine the visual appeal of simple and complex product packaging to consumers, two stimulating materials were simultaneously presented on the screen. To control for potential positional deviations, participants were randomly assigned to the complex conditions on the left or right.

After the presentation of each set of materials, participants clicked the mouse to proceed to the questionnaire section. Initially, participants were asked to respond to four items related to green trust adapted from Chen [37]. Specific items include “I think that this product’s environmental reputation is generally reliable”, “I think that this product’s environmental performance is generally dependable”, “I think that this product’s environmental claims are generally trustworthy”, and “I think that this product’s environmental concern meets your expectations” (rated on a seven-point scale, with 1 = strongly disagree and 7 = strongly agree; α = 0.89). As a manipulation check, participants were then prompted to report their perception of the packaging complexity: “I perceive the packaging of this product as” (rated on a seven-point scale, with 1 = very simple and 7 = very complex). Given potential variations in aesthetic appeal across stimulus materials, participants were also asked to report their perception of the product’s visual attractiveness: “I think the packaging of the product is aesthetically pleasing” (rated on a seven-point scale, with 1 = strongly disagree and 7 = strongly agree).

3.1.3. Results

Manipulation check: The paired samples t-test revealed a significant difference in perceived complexity between the two levels of complexity for the green products in this experiment (M_complex = 5.056, M_simple = 3.944, t(35) = −9.080, p < 0.001). Furthermore, considering the potential influence of differences in product attractiveness on the experimental results, this experiment examined the differences in perceived attractiveness between the two complexity levels of green products. The results indicated a marginally significant difference in perceived attractiveness (M_complex = 4.639, M_simple = 3.944, t(35) = −1.771, p = 0.085).

Heatmap analysis and gaze path analysis: Heatmap analysis is a visualization technique that integrates eye-tracking data from multiple participants to describe their visual behavior characteristics, providing an intuitive representation of individual attention and interest in specific areas [38]. Different colors are employed to indicate the fixation duration for each region, with red representing the most concentrated or longest fixation duration, followed by yellow, while green indicates the shortest or briefest fixation duration. The current experiment’s heatmaps are illustrated in Figure 3a,b. The heat map analysis reveals that, regardless of the product presentation order, the heat distribution for the simple condition is relatively more concentrated compared to the complex condition. The primary areas of focus include the brand name at the top of the packaging, as well as the content related to sustainable product ingredients and benefits at the bottom, which are closely associated with sustainable product attributes. In contrast, in addition to these core informational areas, the complex condition elicited higher interest in the decorative cues, which, while important for product recommendation, do not directly pertain to sustainability. Gaze path analysis, as depicted in the selected representative participants’ eye movement trajectories, provides insights into the comprehensive process of consumer attention. In the gaze path visualizations, the circles represent fixation points, with the size indicating fixation duration, and the connecting lines denote saccadic amplitude, with numbers representing the order of fixation. As shown in Figure 3c, when the stimuli were presented, participants were initially drawn to the complex condition, with their gaze initially focused near the brand name, but then quickly shifting to the decorative elements and dwelling on them for a relatively long time, indicating that this aspect generated higher interest. Participants’ visual attention subsequently shifted to the simple condition material on the left, but they only briefly scanned it without sustained focus before returning their gaze to the complex condition. A similar pattern is observed in the gaze path visualization in Figure 3d, where participants frequently scanned the materials on the left and right sides. Participants were first attracted to the complex material on the left, then shifted their gaze to the simple condition material on the right, and after completing the observation, redirected their focus back to the left side for more detailed examination. The gaze pattern analysis suggests a competitive dynamic in participants’ visual attention allocation between the two product presentation conditions. Irrespective of the order in which the stimuli were displayed, participants exhibited a tendency to continuously scan and shift their gaze between the complex and simple packaging conditions, indicative of a contest for attentional resources. However, the visual behavior characteristics diverged markedly between the two conditions. Under the complex packaging condition, participants demonstrated a more dispersed fixation pattern, with a greater number of shorter saccadic eye movements and a higher frequency of fixations. This suggests that the complex visual elements, including decorative cues, generated higher levels of interest and cognitive engagement, prompting participants to extensively explore these areas. In contrast, the simple packaging condition elicited a more concentrated visual attention strategy, with participants primarily fixating on the brand name and information related to sustainable product attributes, interspersed with fewer yet larger saccadic amplitudes. This pattern indicates a more focused and efficient visual information processing approach in the simple condition, as participants were able to rapidly extract the salient sustainability-relevant cues without becoming overly distracted by extraneous design elements. These findings suggest that while the complex packaging condition may have initially captured participants’ attention, the simple condition enabled more targeted encoding of the critical sustainability information. The comparative analysis of the gaze patterns illuminates the trade-off between the visual salience of design elements and the cognitive resources required to process them, with important implications for the strategic communication of sustainability attributes in product packaging design.

Eye movement metrics and green trust: To further examine differences in visual attention across various areas of interest (AOIs), this experiment delineated distinct regions within the visual stimuli, including the total area encompassing the entire product, the text area covering the textual information on the sustainable product packaging, and the image area covering the non-textual elements. The descriptive statistical results of the total fixation duration and the total number of fixation points in different interest areas under different packaging complexity conditions are shown in

Table 1. Descriptive statistics of total fixation duration and number of fixations in different areas under different packaging complexity conditions.

Group	Simple Group			Complex Group
AOI	Text area	Image area	Total area	Text area	Image area	Total area
Total fixation time	1.517	1.856	3.373	1.589	2.997	4.586
	(0.794)	(1.448)	(1.153)	(0.892)	(1.519)	(1.354)
Number of fixations	4.667	7.111	11.778	4.833	9.806	14.639
	(2.414)	(4.701)	(3.727)	(2.158)	(4.515)	(4.467)

Note: The standard deviations are in parentheses.

. Paired samples t-test analyses were employed to compare the number of fixation points and fixation durations across the distinct AOIs. The visualized results are shown in Figure 4. The results indicated that the total fixation duration within the total area was significantly greater for the complex product condition compared to the simple product condition (t = 3.119, p < 0.01). However, no significant difference emerged between the text area fixation durations for the complex and simple product conditions (t = 0.505, p = 0.616 > 0.1). Conversely, the total fixation duration within the image area was significantly longer for the complex product condition relative to the simple product condition (t = 2.731, p < 0.01). Similarly, the number of fixation points within the total area was significantly higher for the complex product condition compared to the simple product condition (t = 2.578, p < 0.05). No significant difference was observed between the text area fixation point counts for the complex and simple product conditions (t = 0.353, p = 0.726 > 0.1). Nonetheless, the number of fixation points within the image area was significantly greater for the complex product condition than the simple product condition (t = 2.300, p < 0.05). For the simple product condition, no significant difference emerged between the fixation duration of the image area and text area (t = 1.001, p = 0.324 > 0.1), though the number of fixation points was significantly higher in the image area compared to the text area (t = 2.264, p < 0.05). Conversely, for the complex product condition, the total fixation duration (t = 4.039, p < 0.001) and number of fixation points (t = 5.434, p < 0.001) were both significantly greater in the image area relative to the text area. These quantitative findings aligned with the heat map and gaze trajectory visualizations, collectively suggesting that the complex product condition elicited greater visual attention than the simple product condition, with this increase in attention predominantly focused on the decorative elements rather than the textual information.

3.1.4. Discussion

The findings from Experiment 1, which utilized a combination of eye-tracking and survey methodologies, revealed a contradiction between the visual appeal of complexity and consumers’ green trust. The results demonstrated that participants exhibited a greater visual interest in complex product packaging. Heat map analyses and gaze path visualizations highlighted a visual competition effect between decorative elements and green information cues. Compared to the simple packaging condition, the complex packaging stimuli elicited increased gaze durations and higher numbers of fixations on the decorative features. However, this heightened visual attention corresponded with a decreased level of trust in the products’ green attributes despite the green information being consistent across the two packaging conditions. This finding aligns with prior research indicating that decorative elements and functional properties often serve as opposing indicators, as decorative features are initially unrelated to the core product functions [23]. Similarly, in the context of green product packaging, this decorative allure is also disconnected from the true green performance of the item, potentially reflecting a manipulative marketing tactic that could breed consumer suspicion. While Experiment 1 provided valuable insights into the explanatory mechanism underlying the impact of packaging complexity on green trust through the lens of visual attention, there are some limitations that warrant further investigation. For instance, the color composition of the experimental materials may have influenced the results, and the eye-tracking data may not have fully captured the breadth of consumers’ real-time psychological experiences. Consequently, additional research is needed to elucidate this phenomenon more comprehensively.

3.2. Experiment 2: The Mediating Role of Manipulation Inference

Experiment 1 validated the effect of packaging complexity on visual attention and green trust. This finding reflects the role of packaging complexity at the physiological level to a certain degree, but the underlying psychological mechanism remains unclear. Therefore, Experiment 2 aims to investigate further the mediating mechanism by which packaging complexity influences green trust. Additionally, Experiment 2 accounts for the effects of two distinct packaging pattern types (natural elements and non-natural elements) in order to control for the potential confounding influence of pattern type on green trust. By comparing the results of these two experiments, the researchers hope to provide a more comprehensive understanding of the mechanisms by which packaging complexity affects consumer psychology and behavior. Specifically, Experiment 2 aims to investigate the role of manipulation intention inference as a potential mediating variable. This would contribute to a deeper theoretical foundation and practical guidance for sustainable product and packaging design.

3.2.1. Participants

Participants, recruited from the esteemed Credamo platform, actively engaged in Experiment 2. In Experiment 2, 303 individuals participated, with 138 (45.54%) male participants. The educational background of the participants was diverse, with 10 individuals (3.3%) having a high school/vocational school/technical school degree, 29 (9.57%) having an associate’s degree, 203 (67%) having a bachelor’s degree, 44 (14.52%) having a master’s degree, and 17 (5.61%) having a doctorate degree.

3.2.2. Procedures

Prior to the start of the experiment, participants provided informed consent. Analogous to Experiment 1, participants were instructed to envision themselves in the process of purchasing laundry detergent. Subsequently, participants were randomly assigned to one of three experimental conditions: a simple packaging group, a complex packaging group featuring natural design elements, or a complex packaging group with non-natural design elements. The stimulus materials were designed based on the “number of elements” principle. Additionally, this experiment controlled for the effect of product color to mitigate the potential influence of increased color variety on the experimental outcomes. In order to investigate the impact of distinct decorative packaging patterns, the level of packaging complexity was manipulated by varying the number of natural and non-natural design elements. The stimulus materials are depicted in Figure 5, presented from left to right as the simple packaging group, the complex packaging group with natural elements, and the complex packaging group with non-natural elements. It is important to note that despite the differences in packaging complexity, all experimental materials conveyed consistent informational content.

First, in order to verify the rationality of the experimental material settings, the subjects were asked to evaluate the packaging complexity of the products. Following this, participants evaluate their level of green trust in the product (α = 0.76). Subsequently, participants assess their manipulation inference of the packaging design, responding to statements such as “I think the pattern on the packaging endeavors to influence my purchasing decision”, “I think the pattern on the packaging seeks to persuade me solely for its marketing purposes rather than aiding my optimal decision-making”, and “I think the pattern on the packaging attempts to manipulate my purchasing behavior” (using a seven-point scale, with 1 = strongly disagree and 7 = strongly agree; α = 0.83). An attention check question is incorporated, necessitating participants to select the fourth option out of seven. Additionally, participants rate the aesthetic appeal of the packaging. Finally, participants provide their demographic information, and appropriate compensation is disbursed. In addition to substantiating the mediating mechanism of manipulation inference, this experiment contemplates alternative explanations. Prior research has demonstrated that a simple packaging design for champagne products can enhance perceptions of brand authenticity. Building upon this foundation, the present investigation examines whether this heightened sense of authenticity evoked by simple packaging subsequently leads to greater perceived trustworthiness of the product. Consequently, this experiment measures perceived brand authenticity. Participants were asked to respond to three items related to perceived brand authenticity [39].

3.2.3. Results

Manipulation check: To examine the perceived complexity of the three stimulus materials (simple, complex with natural elements, and complex with non-natural elements) in relation to sustainable product perception, a one-way analysis of variance (ANOVA) was conducted. The results indicated significant differences in perceived complexity among the three groups (M_simple = 1.825, M_{complex with natural elements} = 3.121, M_{complex with non-natural elements} = 2.822, F(2,300) = 24.19, p < 0.001). Post hoc comparisons revealed that the complexity level of the simple group was significantly lower than that of the complex group with natural elements (p < 0.001) and the complex group with non-natural elements (p < 0.001). There was no significant difference in complexity between the complex group with natural elements and the complex group with non-natural elements (p = 0.315 > 0.1), indicating successful manipulation of packaging complexity. Additionally, the experiment examined the perceived aesthetic appeal of the three stimulus materials. The results showed no significant differences in perceived aesthetic appeal among the three groups (M_simple = 5.583, M_{complex with natural elements} = 5.434, M_{complex with non-natural elements} = 5.356, F(2,300) = 1.22, p = 0.298 > 0.1). Post hoc comparisons revealed no significant differences in perceived aesthetic appeal between the simple group and the complex group with natural elements (p = 0.607 > 0.1) or the complex group with non-natural elements (p = 0.310 > 0.1). There was also no significant difference in perceived aesthetic appeal between the complex group with natural elements and the complex group with non-natural elements (p = 0.872 > 0.1).

The mediating effect of natural element complexity: To test the hypotheses, a series of multiple regression analyses were conducted following Baron and Kenny’s three-step mediation analysis [40]. Packaging complexity was transformed into a dummy variable (0 = complex with natural elements, 1 = simple). After taking gender and education level as control variables, the results of the multiple regression analysis are shown in

Table 2. Hierarchical regression analysis to validate mediation effects under natural elements conditions.

	Model 1	Model 2	Model 3
Variable	Green Trust	Manipulation Inference	Green Trust
Packaging complexity	0.395 **	−0.320 *	0.214 *
	(0.128)	(0.157)	(0.089)
Manipulation inference			−0.566 ***
			(0.087)
Intercept	5.296 ***	2.341 ***	6.620 ***
	(0.277)	(0.338)	(0.283)
N	202	202	202
F	4.153	1.998	16.31

Note: Robust standard errors are in parentheses. The *, **, and *** indicate significance at the 5%, 1%, and 0.1% levels.

. Model 1 demonstrated a significant positive effect of packaging complexity on consumers’ green trust (β = 0.395, p < 0.01), supporting H2. Model 2 showed a significant negative effect of packaging complexity on consumers’ manipulation inference (β = −0.320, p < 0.05). Model 3 revealed that packaging complexity still had a significant effect on green trust (β = 0.214, p < 0.05), even when accounting for the mediating variable of manipulation inference. This indicates that manipulation inference partially mediates the relationship between packaging complexity and green trust, supporting H3. In addition, the results of the Sobel–Goodman test showed that the mediation effect accounted for 45.8% of the impact of packaging complexity on green trust, with an indirect effect size (a × b) of 0.181 (p < 0.05), a direct effect size (c’) of 0.214 (p < 0.05), and a total effect size (c) of 0.395 (p < 0.05).

The mediating effect of irrelevant element complexity: We converted packaging complexity into a binary variable (0 = complex with irrelevant element, 1 = simple). Using packaging complexity as the independent variable, green trust as the dependent variable, and manipulative intent inference as the mediating variable, we conducted a test for the mediating effect, controlling for the influence of gender and education level. The results are shown in

Table 3. Hierarchical regression analysis to validate mediation effects under non-natural elements conditions.

	Model 1	Model 2	Model 3
Variable	Green Trust	Manipulation Inference	Green Trust
Packaging complexity	0.496 ***	−0.393 **	0.362 ***
	(0.085)	(0.13)	(0.081)
Manipulation inference			−0.341 ***
			(0.062)
Intercept	5.295 ***	2.453 ***	6.132 ***
	(0.236)	(0.299)	(0.229)
N	204	204	204
F	11.67	4.419	26.11

Note: Robust standard errors are in parentheses. The ** and *** indicate significance at the 1%, and 0.1% levels.

. The results of Model 1 indicate a significant positive correlation between packaging simplicity and consumer trust in sustainable products (β = 0.496, p < 0.001), supporting H2. Model 2 shows that packaging simplicity has a significant negative impact on consumers’ manipulative intent inference (β = −0.393, p < 0.01). Model 3 reveals that while the regression coefficient of design simplicity on consumer purchase intention decreases (from 0.496 to 0.362), packaging simplicity still has a significant impact on green trust (p < 0.001). This indicates that manipulative intent inference partially mediates the effect of packaging simplicity on green trust, supporting H3. In addition, the results of the Sobel–Goodman test showed that the effect size of the indirect effect (a × b) is 0.134 (p < 0.01), the effect size of the direct effect (c’) is 0.362 (p < 0.001), and the total effect size (c) is 0.496 (p < 0.001). This indicates that manipulative intent inference partially mediates the effect of packaging simplicity on green trust, and the mediating effect explains 27.0% of the total variation, as calculated by a × b/c = 0.270.

The effects of different pattern types under complex conditions: In order to ascertain the potential impact of different types of elements, we employed a binary transformation of packaging complexity (1 = complex with natural elements, 0 = complex with irrelevant elements). Utilizing element type as the independent variable and manipulative intent inference (β = −0.098, p = 0.652 > 0.05) and green trust (β = 0.073, p = 0.460 > 0.05) as the dependent variables, the regression results were found to be statistically insignificant. This implies that the specific pattern of packaging does not exert any influence on the outcomes.

Exclusion of alternative explanatory mechanisms: Furthermore, Experiment 2 delved into the role of perceived sincerity. When packaging complexity served as the independent variable and green trust as the dependent variable, the alternative explanatory variable, perceived sincerity, did not demonstrate a significant mediating effect (indirect path effect = 0.024, SE = 0.030, 95%CI: [−0.033, 0.082]).

3.2.4. Discussion

Experiment 2, employing an online questionnaire, substantiated the correlation between packaging complexity and consumer trust in environmentally friendly products. It unequivocally established that simplistic packaging designs engender higher levels of green trust compared to their complex counterparts. Moreover, Experiment 2 unveiled the pivotal role of perceived manipulative intent as a mediating factor. The insignificance of packaging pattern type was also established, as both nature-related and unrelated complexities eroded consumer green trust. These findings underscore consumers’ astuteness in discerning attempts to sway their attitudes through decorative embellishments, irrespective of the complexity involved. Aligned with the persuasion knowledge model, individuals instinctively resist behaviors that compromise their subjective consciousness. Complexity variations in packaging serve external allure rather than intrinsic functionality, thereby engendering skepticism toward intricate designs. However, the generalizability of these mechanisms to other environmentally friendly products and their consequential impact on purchase behavior remain shrouded in uncertainty. Further inquiry is warranted to elucidate these intricacies and bridge existing knowledge gaps.

3.3. Experiment 3: The Moderating Role of Expertise Level

The purpose of Experiment 3 was to validate the proposed mechanism further regarding the role of packaging complexity in green consumer products, as outlined in this paper. Additionally, it aimed to examine the moderating effect of consumer expertise level. Since trust represents a positive attitude rather than actual purchasing behavior, this experiment introduced purchase intention as a downstream variable to investigate the impact of packaging complexity on green consumption, thus enhancing its practical applicability.

3.3.1. Participants

Participants for Experiment 3 were recruited from the Credamo platform. Before the experiment, participants signed an informed consent form. A total of 200 participants took part in Experiment 3, including 81 males (40.5%). Among the participants, there was 1 participant with a junior high school education (0.5%), 5 participants with a high school/vocational school/technical school education (2.5%), 10 participants with an associate degree (5%), 140 participants with a bachelor’s degree (70%), 39 participants with a master’s degree (19.5%), and 5 participants with a doctoral degree (2.5%).

3.3.2. Procedures

Participants were asked to imagine themselves intending to purchase a laundry detergent. They were then randomly assigned to either the simple or complex conditions. To control for the potential influence of product category, the same laundry detergent used in Experiment 1 was selected as the experimental material. As a manipulation check, participants reported the perceived simplicity of the packaging on a scale from 1 (very simple) to 7 (very complex). Subsequently, participants assessed their level of green trust in the product (α = 0.90). Next, participants evaluated their perceived manipulative intent inference regarding the product (α = 0.87). Participants were then asked to assess their level of expertise by indicating their comparative knowledge of green products compared to their familiar friends on a scale from 1 (less) to 7 (more) and their overall self-perceived knowledge of green products on a scale from 1 (very little) to 7 (a lot) (r = 0.76, p < 0.001). Participants’ purchase intention was also measured (“How strong is your intention to purchase this tissue?”—1 = very weak, 7 = very strong). An attention check question was inserted, requiring participants to choose the fourth option among seven options. The perceived aesthetic appeal of the packaging was also measured (“Do you think the packaging of this product is visually appealing?”—1 = not at all appealing, 7 = very appealing). Finally, demographic information was collected, and participants received compensation accordingly. In addition to validating the mediating mechanism of manipulative intent inference, this experiment considered some alternative explanations. Previous research has found that simple designs have higher processing fluency levels than complex designs [41]. Could the positive experience generated by the fluency induced by simple designs lead to higher levels of trust among consumers? Therefore, this experiment measured participants’ perceived fluency (“I think the claims of this laundry detergent are straightforward to notice” and “I think the claims of this laundry detergent are not noticeable at all”—reverse scored) (r = 0.74, p < 0.001).

3.3.3. Results

Manipulation check: The results of an independent samples t-test, with perceived complexity as the dependent variable, revealed that compared to the complex design group, participants in the simple design group perceived the packaging to be significantly simpler (M_complex = 3.29, M_simple = 2.65, t(198) = 2.965, p < 0.01), indicating the effectiveness of the manipulation of product stimuli. Another independent samples t-test, with perceived attractiveness as the dependent variable, showed no significant difference in perceived attractiveness between the simple design group and the complex design group (M_complex = 5.23, M_simple = 5.39, t(198) = −1.008, p = 0.315 > 0.1).

Mediation effects and moderation effects: Firstly, the packaging complexity was transformed into a binary variable (1 = simple, 0 = complex). Using packaging complexity as the independent variable, green trust as the dependent variable, and manipulative intent inference as the mediating variable, mediation analysis was conducted while controlling for the influence of gender and education level. The results are presented in

Table 4. Hierarchical regression analysis to validate mediation effects and moderation effects.

	Model 1	Model 2	Model 3	Model 4	Model 5
Variable	Green Trust	Manipulation Inference	Green Trust	Manipulation Inference	Green Trust
Packaging complexity	0.535 ***	−0.599 ***	0.198	−0.600 ***	0.136
	(0.138)	(0.156)	(0.102)	(0.163)	(0.095)
Expertise level				0.192	0.126 *
				(0.124)	(0.052)
Manipulation inference			−0.563 ***		−0.466 ***
			(0.073)		(0.062)
Packaging complexity × Expertise level				−0.371 *
				(0.148)
Manipulation inference × Expertise level					−0.235 ***
					(0.055)
Intercept	5.691 ***	2.878 ***	7.312 ***	1.971 *	6.164 ***
	(0.562)	(0.586)	(0.475)	(0.921)	(0.487)
N	200	200	200	200	200
F	5.018	5.585	18.36	4.787	28.95

Note: Robust standard errors are in parentheses. The * and *** indicate significance at the 5% and 0.1% levels.

. Model 1 showed that packaging complexity significantly positively affected consumers’ green trust (β = 0.535, p < 0.001), supporting H2. Model 2 revealed that packaging complexity significantly negatively affected consumers’ manipulative intent inference (β = −0.599, p < 0.001). Model 3 demonstrated that design complexity had no significant effect on green trust (β = 0.198, p = 0.055 > 0.05), while manipulative intent inference had a significant negative effect on consumers’ green trust (β = −0.563, p < 0.001), providing support for H3 and indicating that manipulative intent inference partially mediated the effect of packaging complexity on green trust. Furthermore, to enhance the robustness of the results and validate the magnitude of the mediation effect, the Sobel–Goodman test was employed. The analysis results showed that the Sobel test, Aroian test, and Goodman test reached significant levels, supporting using manipulative intent inference as a mediating variable in the relationship between packaging complexity and green trust. The results indicated that the indirect effect (a × b) was 0.337 (p < 0.01), the direct effect (c’) was 0.198 (p = 0.053 > 0.05), and the total effect (c) was 0.535 (p < 0.001), suggesting that manipulative intent inference partially mediated the effect of packaging complexity on green trust, with the mediation effect accounting for 63.0% of the total variance (a × b/c = 0.630), supporting H3. To examine the moderating effect of expertise level on the relationship between packaging complexity and manipulative intent inference and the relationship between manipulative intent inference and green trust, the interaction term between expertise level and the manipulative intent inference was created by centering expertise level and conducting regression analysis. Model 4 showed that the interaction term between packaging complexity and expertise level significantly affected manipulative intent inference (β = −0.371, p < 0.05), supporting H4. Model 5 revealed that the interaction term between manipulative intent inference and expertise level significantly affected green trust (β = −0.235, p < 0.001), supporting H5.

To further analyze the moderating effect of expertise level, we examined the direction and trends of the moderation effect. When the expertise level was low (mean minus one standard deviation), the positive impact of packaging complexity on manipulative intent inference was not significant (β = −0.205, p = 0.280 > 0.1, 95% CI: [−0.577, 0.168]). However, when the expertise level was high (mean plus one standard deviation), the negative impact of manipulative intent inference on green trust was significant (β = −0.995, p < 0.001, 95% CI: [−1.506, −0.484]). This indicates that higher levels of expertise enhance the inhibitory effect of packaging simplicity on manipulative intent inference, supporting hypothesis H4. When the expertise level was low (mean minus one standard deviation), the negative impact of manipulative intent inference on green trust was significant (β = −0.227, p < 0.05, 95% CI: [−0.435, −0.018]). When the expertise level was high (mean plus one standard deviation), the negative impact of manipulative intent inference on green trust was even more significant (β = −0.733, p < 0.001, 95% CI: [−0.854, −0.613]). This further confirms that higher levels of expertise enhance the inhibitory effect of manipulative intent inference on green trust, supporting hypothesis H5.

The impact of packaging complexity on purchase intention. This study also investigated consumers’ purchase intentions. Using packaging complexity as the independent variable, purchase intention as the dependent variable, and manipulative intent inference and green trust as serial mediation variables, the results showed that packaging complexity influenced purchase intention through the serial mediation effect of manipulative intent inference and green trust (β = 0.261, SE = 0.089, 95% CI: [0.102, 0.452]).

Exclusion of alternative explanatory mechanisms: Furthermore, this study ruled out the role of processing fluency. When packaging complexity was used as the independent variable, green trust as the dependent variable, and perceived fluency as the mediating variable, the results showed that the mediating effect of perceived fluency was not significant (indirect effect = 0.004, SE = 0.022, 95% CI: [−0.045, 0.052]).

3.3.4. Discussion

Experiment 3 examined the impact of packaging complexity on manipulative intent inference, which subsequently influenced consumer green trust and purchase intention. The experiment also analyzed the moderating effect of consumer expertise level. The results revealed that complex packaging elicited consumer vigilance toward manipulative intent in product packaging, leading to a detriment in green trust. Consumers with higher expertise levels were more likely to perceive such manipulative intent and exhibited greater resistance to it, thereby harming green trust. Additionally, this study further explored the influence on purchase intention, thereby enhancing the practical value of this research.

4. Conclusions and Implications

4.1. General Conclusions

Commencing with the examination of visual complexity in sustainable product packaging, this study integrates the information persuasion theory to investigate how visual complexity influences consumer trust in environmentally friendly products. Empirical tests are conducted to enrich the existing body of research on sustainable product packaging design and assist sustainable enterprises in formulating targeted strategies for sustainable design. The findings of this study contribute to green enterprises’ understanding of consumers’ perception of sustainable products, facilitating a mutually beneficial scenario of enterprise development and ecological benefits. This study treats visual complexity as the independent variable, manipulation intention inference as the mediating variable, and green trust as the dependent variable. By combining objective physiological indicators from eye-tracking experiments and subjective scales, the research unveils the disparity between the visual appeal of complex packaging and consumer trust, yielding the following specific findings.

The initial experiment confirms that complex decorative designs attract greater visual attention but come at the cost of reduced trust, corroborating previous research. Psychological studies suggest that complexity stimulates curiosity and encourages exploratory behavior [42,43]. However, this does not lead to a positive level of trust. This contradictory phenomenon may be attributed to the notion that attention-grabbing attributes inadvertently expose potential manipulation and persuasion intentions, which seek to influence consumers’ reception of pertinent information rather than serve the intrinsic performance attributes of the product [22,44]. As previous research has shown, complex design is like a well-dressed persuader [24]. According to the persuasion knowledge model, such attempts to control consumers undermine their favorability. Hence, higher levels of complexity in sustainable product packaging result in diminished trust.

Subsequently, the second experiment further substantiates these observations by demonstrating that packaging designs with simplified aesthetics can mitigate consumers’ susceptibility to manipulation compared to complex packaging designs, thereby enhancing trust in the product’s green certification. This indicates that simple designs are perceived as more genuine, enabling consumers to access relevant information directly rather than being subjected to forced sales content. Notably, this effect remains consistent across variations involving natural and non-natural elements. This is due to both natural and non-natural elements in packaging design being viewed as strategic means to achieve marketing objectives rather than authentic reflections of environmental values. Consequently, complexity in either element yields negative outcomes.

Furthermore, the third experiment reveals the moderating effect of individual expertise, wherein heightened expertise intensifies the manipulation resulting from intricate packaging decoration, subsequently diminishing trust. Consumers with higher expertise possess extensive factual knowledge within mature product domains and exhibit greater cognitive demands, compelling them to evaluate product information meticulously rather than rely on superficial cues [45,46,47]. Consequently, such consumers demonstrate heightened vigilance toward manipulative strategies and exhibit a more pronounced aversion toward inconsequential decorative elements. This increased scrutiny and critical evaluation of packaging cues reflects the nuanced understanding and discerning nature of these informed consumers when assessing the authenticity and integrity of sustainable product claims.

4.2. Theoretical Contribution

Primarily, this study expands and enhances previous research on the antecedents of green trust, surpassing the theoretical perspectives that have predominantly examined factors influencing green trust, such as perceived risk and benefits [48]. Instead, this article delves into the realm of sustainable packaging complexity, deepening our comprehension of green trust and providing practical applications. Prior research has explored certain design preference antecedents, such as aesthetic taste, and has also investigated the downstream effects of design complexity, including brand personality perception, visual attention, and service experience [24,39,49]. As a valuable addition, this study uncovers and confirms the positive effects of simple packaging design in fostering green trust. It is worth noting that previous studies have emphasized the positive effects of simplicity in design, particularly in service environments, where simple design enhances perceived fluency and pleasant experiences, thereby augmenting the attractiveness of the service environment [41]. Given that sustainable consumption is vital, this study enhances research on simple packaging for sustainable fast-moving consumer goods, emphasizing the benefits of simple packaging in sustainable product packaging. This conclusion supplements the existing literature on visual complexity and provides a new research perspective on the controversy between simple and complex design [43,50,51]. Furthermore, this study offers a novel perspective on the persuasion knowledge model by incorporating the concept of manipulative intent inference into the assessment of sustainable product attributes. The mediating mechanism of manipulative intent inference is unveiled by establishing a link between sustainable packaging design and the process of product persuasion and drawing insights from persuasion intent and consumer resistance. Finally, this study broadens the application scope of consumer expertise. It provides a new perspective on green product attitudes in the context of consumer knowledge for sustainable product packaging research.

4.3. Practical Significance

The research findings have significant implications for the design of sustainable packaging, strategic positioning of products, and promotion of conscious consumption of environmentally friendly, fast-moving consumer goods. Companies aiming to highlight the sustainable attributes of their products should opt for minimalist packaging designs. While intricate designs may initially capture consumer attention and enhance perceived effort assessment, caution needs to be exercised regarding the potential negative effects of complexity. Our findings indicate that elaborate designs can undermine consumer confidence in the eco-friendly attributes of the product. For everyday consumer goods, it is more effective to emphasize green features without unnecessary design elements directly. Excessive design may lead consumers to perceive marketing motives, thereby weakening their positive attitudes. Furthermore, this study reveals that the relationship between packaging complexity and green trust is influenced by intuitive perception. Consumers with higher levels of expertise are more discerning toward manipulative intentions in products. Therefore, consumers should rationally evaluate a product’s sustainability attributes during their shopping experiences rather than relying solely on intuition or misconceived perceptions. This rational assessment empowers consumers to avoid consumption traps and enhances their long-term well-being. From both the design and consumer perspectives, this would contribute to the sustainable and effective long-term development of the sustainable industry.

4.4. Limitations and Future Research Prospects

There are certain limitations in this study that future research should address. Firstly, this study concentrates on the complexity of sustainable product decoration and does not delve into whether the complexity of textual information within the sustainable product would yield similar results. Research has indicated that the processing of textual and visual information may differ, with more detailed information descriptions favoring the formation of positive consumer attitudes, which contradicts our findings [50]. Therefore, future research could further explore consumer trust under the joint influence of packaging complexity and information complexity. Additionally, this study’s focus lies in the relationship between attention-grabbing and green trust. However, this study only explored green trust, and it remains unclear whether the concept of “trust” in a general sense is applicable to sustainable products. Therefore, future research could expand its investigation to explore other aspects of trust in sustainable products. Furthermore, although this study identifies the moderating role of consumer expertise in the impact of manipulative intent inference on green trust, future research should verify whether these effects are influenced by other boundary conditions. For instance, individuals with holistic thinking tendencies tend to focus on the whole rather than the parts, and they are more inclined to consider the compositional elements together, while those with analytical thinking tendencies exhibit the opposite pattern [51]. Based on this speculation, analytical thinking may lead consumers to perceive packaging complexity as independent or disconnected from product efficacy, thereby weakening the impact of packaging complexity on product efficacy. Similar boundary issues are worth investigating in future research to determine the target objects and applicable contexts of such effects.