The use of eye tracking in combination with other
biometric devices, provides an objective means of evaluating the effectiveness of packaging.
Eye trackers generate a range of metrics that quantify consumers’ viewing behaviour, while
other biometric devices provide additional metrics related to their emotional responses,
motivations, and level of engagement while viewing the packaging.
The use of these devices is likely to gain momentum as they become more affordable, and as more testing facilities
emerge.
Research on shelf impact should be conducted either in a physical store or
in a setting where the store shelf is replicated, such as those found in packaging testing
labs. One such example is CUshop,
located at Clemson University’s Sonoco Institute for Packaging Design and Graphics, which
leverages eye tracking in combination with galvanic skin response (GSR), EEG, and facial coding.
Shelf impact may also be evaluated using virtual shelves populated with digital
images of packs. Respondents view these digital mock-ups on computers coupled with screen-based
eye trackers, in a controlled location setting. This approach is more cost-effective and may be
preferable in the early stages of the development process.
If the prime objective is to assess the shelf, respondents are asked to browse the display without prompting for
any particular item. On the other hand, to assess findability or the time it takes to find an item, the respondent is prompted to
search for the item.
The eye tracker records gaze points, fixations, and the duration and order of fixations. It reveals what the
respondent is viewing over the brief time that they browse the shelves. Gaze plots describes the user’s gaze pattern, and heat
maps, like the one depicted in Exhibit 14.5, summarize the viewing behaviour of the respondents in terms of “heat intensity”,
revealing the red-hot spots, warm (yellow, green) and cold spots.
Typically, we do not require large samples for eye tracking studies. If the research is qualitative in nature, a sample
of 10 to 15 should suffice. For quantitative studies, a sample of 20 to 40 should be adequate.
The size of the sample depends on the variance — we need larger samples if consumers vary greatly on how they look for
a product on shelf. This is unlikely to be the case, yet other than prior benchmarks, there is no way to determine the variance prior
to the research.
You could however, track variance and aggregated heat maps as you progress, and add more respondents if the variance
suggests that you need a larger sample to meet the desired level of significance. Quite often though, you may not find much change
in the heat map from a sample of 20 to a sample of 30.
Eye tracking highlights what consumers’ notice and what stands out. However, it does not reveal what consumers perceive
or how they feel about the packaging. Do consumers like the packaging? Is it standing out for the right reasons?
These questions are best answered via qualitative research techniques.
Combining eye tracking with other biometric techniques for measuring consumers’ emotions and motivations, and their
level of engagement provides a better-rounded understanding of the impact of packaging on the shelf.
GSR reveals physiological arousal due to excitement, attention or anxiety.
EEG detects brain activity revealing
respondents’ level of attention and engagement, workload or the extent to which they are mentally stretched, and their motivations
in terms of positive-negative feelings and approach-avoidance. Facial coding
helps interpret their facial expressions revealing
emotions that are outwardly displayed. These techniques are detailed in Chapter Biometrics.
