to do so because long fingernails are highly valued by their social group. Similarly, some people may avoid having their photographs taken for a face recognition system because of concerns over how the images will be used; others will avoid this owing to concerns about the absence of customary adornments to the face (for example, scarves). In both cases system performance may be compromised.

The proportionality of a biometric system—that is, its suitability, necessity, and appropriateness—in a given context will have a significant effect on the acceptability of that system.1 The societal impact of such systems will vary significantly depending on their type and purpose. For example, the use of iris scanning to control access to a local gym and of finger imaging to recognize suspected terrorists at international borders are likely to differ, both for the individuals being scanned and the broader community. The potential impacts on particular social groups and thus their receptions by these groups may also vary dramatically due to differences in how the group interprets the cultural beliefs, values, and specific behaviors. Imposing facial recognition requirements to enter a store or workplace may limit the shopping and work options available to individuals who consider photographs of faces inappropriate, creating barriers to social activities.

This chapter explores such considerations in four areas: biometric systems and individual participation, potential impacts on society of biometric systems, legal considerations with respect to biometrics, and data collection and use policies.


System performance may be degraded if social factors are not adequately taken into consideration. These factors are of two types, those that motivate and those that facilitate participant engagement with the system.

Motivating Participation by Individuals

As a rule, peoples’ willingness to participate in a system and their commitment to it depend on their understanding of its benefits. For example, a biometric system that allows convenient access to a worksite might be perceived as beneficial to individuals by relieving them of the necessity


European Commission, Article 29. The Data Protection Working Party observes that proportionality has been a significant criterion in decisions taken by European Data Protection Authorities on the processing of biometric data. Available at

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