This eye tracking study explored the effects of varied positioning of food label information on consumer attention to the food label when controlling for chromaticity. There is a dearth of empirical studies that measure the effects of variations to complex label systems and their effects on consumer attention to specific label components. Retailer and manufacturer strategies to improve grocery store food labeling may favorably influence the perceived benefits of shopping in brick and mortar stores.
Increased adoption of online grocery shopping with home delivery or shop-online and pick up in store highlight the importance of offering differentiated in-store shopping experiences. A critical component of favorable store shopping experiences is maximizing the customer's perceived utility by increasing convenience during food labels evaluation and selection of product alternatives to meet consumer goals. Brick and mortar stores offer customers the advantage of inspecting multiple products which are organized by department classification when creating their shopping basket. The process for selecting products among large in-store assortments however is less than optimal due to hyper-segmented assortments and consumer information overload when evaluating grocery product alternatives. Improvements to food product labels may also facilitate the evaluation and selection of product alternatives. Brick and mortar stores have associated consumer costs for travel and access to stores, wayfinding, product handling and checkout processes. Each of these associated consumer opportunity costs reduce the utility of the in-store shopping experience. Improving the brick and mortar grocery shopping experience for consumers by improving the accessibility of important label information may reduce A) Time requirements to evaluate products B) Reduce shopping time and C) Reduce store labor costs related to customer service. Consumers react to food label information in different ways due to their specific shopping trip goals. Competition for a consumer's visual attention between competing product label messages is presumed to be governed by a consumer's idiosyncratic wants and needs when shopping. Patterns in the ways that groups of consumers evaluate food label information may offer insights into ways of organizing key label information to increase the flow of relevant information.
Food labels help consumers prioritize relevant information when evaluating and selecting food alternatives and may influence attention towards products . Retailers frequently emphasize brand, product, and marketing claims (e.g fresh, natural) in front of package food label messages. Label information has been demonstrated to influence purchase behaviors based on the type of information provided . Research using eye tracking suggests that simplified food label designs may influence increased attention to the food label messages . Detailed food product information is generally found on the side and back panels of packages. Customers seeking additional product information such as the country of origin, safe handling, preparation and use instructions, product warnings, ingredients and nutritional information are often required to remove food products from shelves and turn them to access the additional information.
Increasing convenience for grocery shoppers through effective food label design requires a better understanding of how consumers prioritize competing label information in front of package label communications. The goal of saving customers time through effective organization of key label information may offer perceived customer advantages to shopping in the brick and mortar channel combining both the benefits of immediate delivery of products and shopping time savings.
The role of colored label stimuli including imagery, background and text has been found to influence consumer attention favorably compared to monochrome messages . However, the ability of the label message to transfer information to consumers effectively controlling for chromaticity within a complex label system including varied product information has not been studied. The ways in which monochrome and color images transfer information to consumers are likely contingent on placement, context, content and design of the label message. A label system must further compete for the consumer's attention based on the consumer's goals and interpretation of competing food product label messages which influence decision making. Front of package label messages which are both clear and easy to interpret to maximize the consumer's convenience and facilitate purchase decisions are presumed to support retailer best practices in packaging design.
Eye Tracking Overview
Eye tracking technology measures 2D or 3D stimuli using screen, head mounted, or eyeglass instruments. Fixations measure pupillary dilations at or above the 100 millisecond range and include the diameter of the pupil's dilation during label observations. Saccades measure the movements of the eye including the paths and order in which visual stimuli are scanned. 2D computer screen based eye tracking measures pupillary fixations and saccadic eye movements describing gazing patterns of predefined visual stimuli presented on a computer screen.
Fixations and saccades may predict a consumer's cognitive processing behavior . The design of label information has been demonstrated to influence consumer choices measured with eye tracking (Chrea, et al. 2010; Tonkin, Ouzts & Duchowski 2011; 3).
Eye tracking research has suggested that combinations of bottom-up or top-down cognitive processing may be involved when shoppers prioritize and evaluate label information [6,7]. Bottom-up processing involves cues such as the lines, shapes and colors of a stimuli subconsciously or consciously to influence consumers. By contrast, top-down processing requires conscious cognitive effort by drawing on the consumer's memory, emotions, and higher order cognitive evaluation of specific product attributes which influence overall product evaluations and purchase decision making. Food label information may stimulate consumer's bottom-up and top-down processing behaviors.
For purposes of this study, pupillary fixations in the range of 100 milliseconds or greater are assumed as markers of either bottom-up or top-down cognitive processing as consumers attend to various label information . Extended time spent fixating or gazing at visual stimuli such as labels may also provide some evidence of top-down processing . Physiological behaviors in eye tracking are quantified through the use of fixation and saccadic data independently or in combination with qualitative or quantitative analysis techniques. Heat maps are qualitative visual representations of measured stimuli showing areas which produce greater attention as measured through pupillary fixations with red gradients indicating greater attention to label areas of interest. Gaze path animation videos describe the timeline of participants' fixations and their order and direction for label observations within predetermined time limits. AOI hits are quantitative measures of fixation behavior within specified areas of interest compiled from the raw eye tracking data file.
Labels support food packaging by providing shoppers with product information, while not necessarily contributing to the protection or storage of products. Labels provide the means for transmitting encoded product information to consumers. Labeling plays a role in presenting consumers with important product information in addition to inspection of a physical product's appearance for some consumer packaged food products. Labeling standards for food products are regulated to varying degrees by various governmental and non-governmental global regulatory authorities. Labeling regulations help to ensure that standards for product communication such as price, weights and measures, and other food product attributes are transmitted consistently to consumers. The interpretation of label information is presumed to occur within a consumer's rationale for considering products and is contingent on the desire to satisfy utilitarian or hedonic needs . Maximizing benefits of the consumer's time spent evaluating products versus their effort required during purchase decisions is frequently influenced by labeling information . Decoding label messages provides consumers one means of evaluating food product alternatives while grocery shopping. A consumer's consideration set for food products may be further influenced by experience or credence from purchasing the food in the past or by in-store promotional and visual merchandising factors. Myriad factors may contribute to a consumer's approach or avoidance behavior for products under consideration in stores. Many grocery products use packaging and labeling to support the sale of food products which influence the consumer's purchase decisions. The opportunity to draw attention to products through the use of imagery in label designs is well documented [5,10]. Imagery provides meaning and context for consumers when evaluating visual information and has been shown to influence consumer bias strength based on the form and location of information presented . Bottom-up design label factors such as bold contrasting colors have also have been demonstrated to influence consumer choices through perceived healthiness of food products [12,13]. Chromaticity of the label may influence the effectiveness of the information transfer to consumers as observed in scan path entropy observed among label areas of interest.
Scan Path Entropy
Scan path entropy provides a means of decoding how consumers evaluate label information through the use of information theory . The process through which consumer decodes the label information may include bottom-up or topdown processing behaviors. Scan path entropy is a hybrid approach of analyzing visual behavior combining participants' pupillary fixations and gaze path observations within an eye tracked visual communication. Scan path entropy statistics combine the logarithm of probabilities in a timeline of discreet choices of ordered observations within specified areas of interest in a visual stimulus . Scan path entropy may offer benefits to researchers when used in combination with traditional eye tracking measurements (e.g. fixation duration, fixation count, time to first fixation, area of interest hit count) to better quantify visual behavior by combining fixation and saccadic observational metrics into entropy statistics. Entropy statistics describe the degree of randomness of participants' gaze observations within and across the message content. Lower entropy scores within a component area of interest indicate more stable flow of information among groups of consumers who decode the label information in similar ways as a group .
The U.S. beef industry is valued at $105 Billion . The average consumer in the U.S. spent $258 in 2015 on meats, poultry, fish and eggs . Research has demonstrated that beef consumers are influenced by perceived convenience, price, safety and variety of meat products . Recent consumer beef purchasing trends highlight nutrition, health concerns, sustainability and local production as emerging factors influencing purchase decisions . In spite of many factors that influence consumer choices of beef products, typical meat department labeling of beef products has remained relatively parsimonious to highlight the appearance of the beef products using translucent cellophane overwraps and small labels. The most common grocery prepackaged beef labeling is a small monochrome printed label highlighting key information which is applied to a cellophane overwrap of meat presented on a Styrofoam tray. The introduction of color printed labels to traditional meat department monochrome labels may increase consumer attention to label messages. Research has suggested that increasing benefits to consumers through increased product information cues and convenience are key variables to combat migration to shop online/pick-up in store strategies . Another benefit of improving our understanding of consumer and label interactions may include ways of differentiating label designs among competitors. Designing more effective front of package food labels offers one such approach to combat rising consumer expectations in grocery stores compared to time saving online shopping alternatives. Research has also found that label design factors may directly influence perceived salience of marketing communications .
This study measured consumer label viewing behavior of variations of a front of package beef steak label info using eye tracking. Two hundred and eighty-two participants (180 females, 102 males) with ages ranging from 18 to 60+ years (M=38.5 years, SD=7.46) were recruited to participate in the study. All of the participants reported regular color vision and normal to corrected to normal vision using contact lenses or glasses. A flier and email recruiting campaign was conducted at a large Midwestern University and within grocery stores in the nearby community with the permission of store management. Study selection criteria required that participants had purchased items in grocery stores on at least a monthly basis. Participants reported the following grocery purchasing behaviors: 43% made all of the purchasing decisions, 39% made most of the purchasing decisions, and 18% made some of the purchasing decisions for their household. The experimental protocol was reviewed by the university internal review board and participants completed informed consent documents prior to beginning the eye tracking experiment. Participants received $15.00 compensation for participating in the study.
Eye Tracking Device
A Tobii X 2-30 eye tracking system was used to conduct this study and data was analyzed using Tobii Studio Pro Software v 3.3.1. The eye tracking system is permanently mounted to a 17" computer monitor. The device measured participants' visual fixations and gaze observations of a preprogrammed eye tracking script consisting of 24 beef steak label images presented on the computer monitor. A calibration process was followed by participants' exposure to a counterbalanced eye tracking script to reduce learning effects during the repeated beef label exposures.
A novel colored label designed for packaged beef steaks like those sold in open-sell grocery store cold meat cases was digitally created in partnership with a regional grocery chain (Figure 1) Participants reviewed instructions explaining that they would review variations of the same meat label and were asked to look at parts of the label that most influenced their attention as they might do while shopping. Each label variation exposure lasted eight seconds prior to advancing to the next image and label variation. The regional grocery retailer's brand iconography and value proposition for locally produced meats were included in the label stimuli in addition to an icon based safe handling messages and a simplified stop light nutrition message. The monochrome label information panel served as the control condition for comparing the effects of color between the label designs. Each of the five included label sections were posited to influence attention to similar or varying degrees during each label exposure variation. The image variants were created with Adobe Photoshop CC 2015 and Microsoft Publisher 2013. The six image variants in the current study (i.e. three monochromes and three colored) were displayed at 600 X 450 pixels with equal mean illuminance centered against a black background at a total resolution of 1920 X 1080 pixels. The label size displayed on the
computer screen at 3 1/2" X 4 3/4".
The experiment was conducted in a university laboratory simulating a grocery store environment and was illuminated with fluorescent bulbs at an average illuminance of 400 LUX at level of the eye tracking computer screen. Prior to beginning the eye tracking experiment, participants completed a paper survey measuring food label use and demographic information. Each of the participants sat at a table containing the eye tracking computer at a distance of 24 inches from the computer screen in a stationary desk chair. A nine-point calibration process integrated into the Tobii Studio Professional v 3.3.1 software was completed for each participant and evaluated by the research team to ensure the equipment was functioning properly and visual behavior was captured within software specifications. Prior to review of the experimental images, the following instruction screen was read by each participant, "On the next several slides, you will see images of meat labels. Focus with your eyes on areas of the labels that most attract your attention as if you were shopping in a grocery store. The slides will change automatically." Participants were exposed to each of the six label variations for 8000 milliseconds with the goal of measuring attention effects based on chromaticity. The participants eye movements were recorded at 60 Hz.
The characteristics of participants are presented in Table 1. Within the Tobii Studio Professional v 3.3.1 software, five areas of interest (AOIs) were specified for analysis in this study. AOI hit count data was aggregated from the eye tracking raw data file. The aggregated AOI hit counts provided baseline comparisons for entropy statistics of how specific label communications influence consumer attention to the messages presented including the region of production, nutrition, information panel, brand, and icon based safe handling information (Figure 1).
Entropy is a method for quantifying the amount of information presented when discreet probabilities govern how the information is cognitively processed . The assumptions of entropy are that consumers are more likely to focus varied attention on areas of interest when assessing information in a system . Scan path entropy is a method applied to fixations and gaze path behavior (saccades) to compare the relative attention paid to specified AOIs controlling for the order of the AOI observations. Five AOIs were specified within the meat label in each of the six image placement variations including map, brand, info box, nutrition, and safe handling messages. The process for aggregating the gaze behavior was completed using the following steps: 1) Specification of the AOIs 2) Assigning a character to each AOI (e.g. I = info block, N=nutrition, etc.) 3) Determining the fixation order for each observed AOI from individual participant gaze tracing videos 4) Removing duplicate characters 5) Counting unique scan paths and transforming characters to integers representing each AOI (1-5). 6) Applying the entropy formula to the resulting data . The AOI content tested included a map of Oklahoma including the state flag and text, "Proudly Produced in", a local retailer brand logo, a product information panel, a stop-light nutrition summary panel, and icon-based safe handling instruction summary. Participant gaze paths and pupillary fixations on detailed portions of each AOI region may be specified to quantify attention to messages within each area of interest. For example, determining the entropy of the state flag image compared to either the local product or larger map image information transfer to participants. The specific order in which label sections were prioritized by participants among the six label variants and five areas of interest provided the sample of label information responses used to measure scan path entropy in this study. Future studies will explore the AOI hit counts and entropy statistics within specific AOIs to better understand granular effects on attention within variations to AOI designs. For the current study, each AOI in the label placement variations provides an entropy statistic which may be compared within and between images. Since the tested AOIs differed in pixel size on the labels, each AOI was weighted using Poisson Weighting to account for size variations within the label stimuli.
The scan path entropy formula is listed below.
Total label AOI hit count statistics for the beef steak label placement variants are presented in Table 2. For the monochrome label variants, the information box produced the greatest number of AOI hits M=1485, SD 265). In the color label variants, the nutrition information summary produced the greatest number of AOI hit counts M=1458, SD 274. The map area of interest produced the lowest AOI hit counts across both the monochrome and color conditions at M=487, SD=139 and M=424, SD =111 respectively.
The lower AOI hit counts may be explained by the relative size of the map AOI compared to other label AOIs, placement at the top or center of the label stimuli supporting  where top and centrally placed label information is prioritized during visual
processing. Another reason for lower AOI hit counts for the map image may have been influenced by the familiarity of participants with the state where the study was conducted.
Scan path entropy compensates for label stimuli size variations by equally weighting the number of pixels presented within the visual field (Table 3). In addition, the scan path entropy method quantifies label fixations and gaze path order effects and reduces signal noise from repeated observations within an area interest. The rank order of AOI observations provides a hierarchical order of ways that participants evaluate the label information individually which are then aggregated to produce group statistics for how the label was observed. Entropy statistics from the current study suggest that for the control condition information panel which is monochrome (e.g. bordered black and white text) in both the monochrome and color treatments produces less stable information transfer indicated by higher entropy statistics regardless of label position (top, center, bottom) when observed with other colored label information present (Table 4). This finding supports prior research suggesting positive effects on attention of colored label stimuli . Variations in observed entropy between monochrome and color variations highlights the need for further research which expands AOI placement variations to multiple label positions while controlling for the observed entropy of the information panel across label conditions (top, center, bottom).
The monochrome labels produced lower entropy and greater information transfer than the same information presented in color which is likely related to participant attention effects produced by the contrasting colors compared to black and white gradients (Table 5). The map H(x)=2.20, brand H(x)=2.18 and safe handling icons H(x)=1.31 produced lower entropy statistics consistent with the AOI hit count statistics in the monochrome condition. However, when weighted for AOI pixels, entropy statistics suggest that researchers relying solely on AOI fixation hit count statistics could misinterpret participant visual behavior when reviewing the label based solely on fixation frequency. For example, the information panel produced over twice the number of AOI hit counts compared to the map, brand, and safe handling areas of interest, however the observed entropy within the AOIs was consistent for the Map H(x)=2.20, Brand H(x)=2.18 and Info Panel H(x)=2.17. In other words, the entropy statistics suggest that the information panel transferred similar information within the label stimuli in the monochrome condition as the map and brand information despite the higher number of fixations evident in the AOI hit count data which aggregates all AOI observations
within the images. The simplified safe handling icon label information consistently transferred greater information to participants in both the color and monochrome treatments and varied label information positions based on the observed lower values of the entropy statistics across all images. The nutrition panel message produced marginally lower entropy in the monochrome conditions similar to the map, brand, info, and safe handling messages. It is interesting to note that the monochrome info panel when combined with color map, brand, nutrition panel and safe handling messages produced greater observed entropy suggesting a reduced information flow in the presence of the competing colored label components (Table 5). Colored label elements consistently increased the observed entropy for each area of interest suggesting a reduced information flow compared to monochrome label elements. Additional study of the phenomenon of mixing monochrome and colored label elements with the goal of increasing observed entropy of targeted label messages is needed.
This finding highlights the potential of the scan path entropy method as a supporting means for evaluating information transfer when compared to fixation count data by reducing signal noise during repeated observations. The application of label design approaches based on scan path entropy could allow retailers to integrate label elements in varied label positions with the goal of increasing entropy effects for portions of the label message while reducing entropy for other critical communications within the label message. Likewise, the scan path entropy approach may offer insights into combining targeted monochrome and color information combinations on food labels strategically to increase the visual flow of information presented to consumers. For example, using colored text to highlight the price in the information box may reduce total entropy within the information box area of interest holding other monochrome label components constant. However, additional research is needed to test this supposition and other practical applications of the scan path entropy method.
Discussion and Limitations
This exploratory study measured consumer attention to five label areas of interest with varied placement on a hypothetical meat label. Observed entropy mean statistics within the five specified label regions remained consistent regardless of top/ bottom and left/right label placement. Entropy statistics observed were higher among color label regions. Safe handling information consistently demonstrated the lowest observed entropy when controlling for chromaticity. The scan path entropy method offers researchers an extension of traditional eye tracking metrics (e.g. time to first fixation, total fixation duration, fixation count, or AOI hit count) to better understand consumer fixations and gaze behavior by providing estimates of the information transferred from message components when the placement of the messages is varied on labels. The relationship between bi-polar ranges of observed entropy statistics within competing label information may correlate to the degree of top-down or bottom-up processing being used among groups of participants to review different parts of label messages. Testing the relationship of top-down or bottom-up processing used when evaluating label messages using eye tracking would benefit from further studies using fMRI, EEG or other methods to assess evidence of cognitive processing to better understand the relationship between scan path entropy statistics and cognitive processing behavior when participants encounter variations in labels or other visual systems. Attempts to strategically place label information based on mean observed entropy in areas of interest to stimulate or reduce channel noise contingent on consumer shopping goals may be possible through application of scan path entropy methods to food label design. Developing a better understanding of consumer goals in food purchases based on how they interpret label messages by incorporating questionnaires also offers a logical extension of this research agenda for the future to further support validity of the method. Measuring the effects of contrasting color combinations integrated into label designs requires future research using the scan path entropy approach. The current study has several limitations which warrant caution when interpreting the results without additional research. The sample is not representative of grocery shoppers in the United States and therefore may not reflect information flow of persons with varied geo-demographic characteristics interpretation of the label information. All participants resided in Oklahoma at the time of the study and were familiar with the local regional retailer tested in the label design variations and results would likely differ for consumers unfamiliar with the retail trade area tested, or when other stimuli were presented for varied geographical regions. Since the participants all demonstrated normal or normal-corrected vision and color perception the observed entropy may vary among persons who are color-blind when examining monochrome and color labels.
Practitioners should consider scan path entropy to evaluate label designs intended to highlight specific information for various purposes including marketing, health communications, and safety messages. Label systems in which information competes for consumer attention appears to be influenced by the use of monochrome or color label components and observed entropy can be influenced by placement and combinations of varied label elements which can be measured and adapted to achieve message attention goals.