Physiological traits are stable physical characteristics, such as palm prints and iris patterns.
This type of measurement is essentially unalterable. Because behavioral characteristics can change over time, the enrolled biometric reference template must be updated each time it is used. Although behavior-based biometrics can be less expensive and less threatening to users, physiological traits tend to offer greater accuracy and security. In any case, both techniques provide a significantly higher level of identification than passwords or smart cards alone. Because biometric traits are unique to each individual, they can be used to prevent theft or fraud.