Eye tracking helps you understand what consumers see; it records their engagement in terms of gazing behaviour. You get to know what consumers gaze at first, how they visually consume the packaging and what attracts their greatest attention. You also can tell whether consumers are finding relevant information on the packs. All these details are summarized in gaze plots and the heat maps.
You can also gauge attitudinal engagement, if other biometric devices are used in conjunction with the eye tracker. EEG would be a good fit because it captures respondents’ feelings, their level of attention and engagement, and the extent that they are mentally stretched.
To tap this information, respondents are asked to pick up and examine packs or prototypes for a short period of time. The eye tracker can capture what each respondent saw when they first glimpsed (5 seconds) the packaging, and what caught their attention over the next 10 seconds.
By measuring respondents’ emotions and their level of attention and engagement, designers can gauge whether the packaging is able to strengthen the brand’s image, and whether the nature of respondents’ engagement and emotions resonate with the brand.
To prevent the bias of one design on another, attitudinal engagement should be monadically tested.
Do note that biometrics does not answer all questions. Eye trackers can tell what people see, and other biometric technologies can reveal their emotions and their level of engagement. None of these devices can tell what they think.
You must continue to rely on conventional qualitative and quantitative research to learn what consumers think, and clearly understand what motivates them, drives their behaviours, and triggers their emotions.