A paper from Peter Pirolli, from PARC, presenting a detailed theory and computational models of the psychology of information scent.
Information scent refers to the detection and use of cues, such as World Wide Web links or bibliographic citations that provide users with concise information about content that is not immediately available.
The information scent cues play an important role in guiding users to the information they seek, and they also play a role in providing users with an overall sense of the contents of collections.
In order to make navigation choices, foragers have a preference function for evaluating interface objects and actions, and a choice rule for selecting among those alternatives based on those evaluations. These evaluations are based on proximal cues on user interfaces.
Evaluation involves a categorization problem in which the information forager must be able to go from past experience and the available proximal cues to infer unobserved features of the distal items.
Models developed in this theory of information scent can predict where people will navigate or what information resources they will select based on their information need.
This also let you to understand what are some reading habits of emails recivers.
More info about this theory of Peter Pirolli click here.