Biometrics Applications


Exhibit 25.22   P&G’s ‘virtual wall’ simulates store shelves using 24 projectors. (source: P&G).

Biometrics has wide ranging applications in marketing, and though its use has be growing rapidly, the potential largely remains under-utilized. The most promising application areas include copy testing, packaging development, product development, and testing of websites.

Programmes should ideally combine biometrics with conventional research, usually qualitative, but quite often quantitative as well. Moreover biometric devices should be used in conjunction, as they complement one another to provide a holistic understanding.

Eye tracking is often the central component as it synchronizes the responses from other sensors with the elements that the consumer is gazing at, so that marketers know exactly what is triggering the emotions. Gaze plots and heat maps reveal what attracts the consumer’s attention, and how she visually consumes the elements of whatever is being tested. The tracking of pupil dilation also provides an assessment of emotional arousal.

Galvanic skin response (GSR) is a useful gauge of emotional arousal, or the intensity of the emotional charge. However, as with eye tracking, it does not reveal emotional valence, so we are unable to tell whether the emotions are positive or whether they are negative. To gauge this important dimension, GSR should be used with facial coding.

The prime advantages of GSR is that it is inexpensive, easy-to-measure, and employs a simple, less invasive device. Its main drawback, other than the inability to measure valence, is temporal resolution. There is a lag, varying from 1 to 5 seconds, between the appearance of the stimulus and the phasic or skin conductance response (SCR). The resulting lack in granularity can make it difficult to disassociate stimuli from each other, if they occur in close proximity in time.

Facial coding can tell us whether the emotional charge is positive, negative, or neutral at any given time. It also categorizes the expressions into one of the six or seven basic emotions.

A compelling advantage of facial coding is that, compared to other biometric techniques, it is much easier and cheaper to implement on a large scale. It uses only a webcam, and requires no controlled location.

Electroencephalography (EEG) provides far better temporal resolution than either GSR or facial coding, allowing for highly granular diagnostic insights. It also yields a richer array of metrics that provide a measure of the level of fatigue, attention, engagement and workload. We can tell which parts of the brain are active while respondents perform a task or respond to stimuli.

Moreover, EEG is immune to masking — a respondent may fake a smile or mask their facial expressions, but the brain cannot be tricked. EEG is able to capture their true emotions.

It is however more invasive — 20 electrodes on the head versus 2 on the fingers. Note, however, that the electrodes are assembled in a manner that makes them fairly quick and easy to place, and that respondents do not experience any discomfort.


In summary, biometrics work best in concert, each revealing different aspects of cognition, emotion and behaviour. The combinations to consider are eye tracking, GSR and facial expression, or eye tracking and EEG. Collectively these techniques provide a clear, multi-faceted understanding of respondents’ engagement with advertising. However, none of the techniques are able to dig into consumers thought processes. We still need qualitative and/or quantitative research to understand what is driving emotions, why something is appealing or why it is not. We still need directed, introspective questions to understand consumers’ purchase disposition, and their attitudinal engagement.

A hybrid approach using conventional copy testing with facial coding is likely to become the standard for pre-testing ads. Further combining with eye tracking and GSR/EEG, would yield deeper insights. Importantly because biometrics is quantifiable and accurate, it should significantly improve the predictive power of copy testing, especially for advertisements that rely on imparting an emotional charge.

A hybrid approach is also recommended for testing packaging where biometrics is increasingly used for assessing shelf impact as well engagement. Eye tracking is the preferred technique, especially for assessing shelf impact. It may be combined with EEG for evaluating engagement.

These applications are covered in detail in sections Shelf Impact — Eye Tracking and Biometrics — Engagement, in Chapter Packaging.

For product concept testing, EEG, eye tracking and/or GSR may be used with conventional qualitative techniques. EEG and facial coding can provide revealing insights in taste testing and sensory research. Measuring pupil dilation through eye trackers is also an option; as the saying goes, “the first taste is always with the eyes”.

For product usage, for instance driving, or the use of apps, eye tracking and EEG are the best options.

Central locations with specialized facilities are usually required for biometrics. For instance, P&G’s ‘virtual wall’, Exhibit 25.22, which simulates store shelves using 24 projectors, or, for instance, GSK’s `Shopper Science’ lab.

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