Introduction to the World of Information Foraging
Information Foraging juxtaposed with Food Foraging
Why Information Foraging came into existence
Information Foraging Theory
Department of Computer Engineering
Manipal Institute of Technology
Foraging Theory is an approach to understanding how strategies and
technologies for information seeking, gathering, and consumption are
adapted to the flux of information in the environment. The theory
assumes that people, when possible, will modify their strategies or the
structure of the environment to maximize their rate of gaining valuable
actively seek, gather, share, and consume information to a degree
unapproached by other organisms. Information Foraging tasks require
increasingly sophisticated information-gathering, sense-making,
decision-making, and problem-solving strategies.
structure of the interface between people and information repositories
in the external world determines the time costs, resource costs, and
opportunity costs of different information foraging and sense-making
strategies. Such costs include access, recognition, and handling costs,
which can be weighed against the rate at which useful information is
delivered to an embedding task.
basic assumption is that people will modify their strategies, or modify
the structure of the interface if it is malleable, in order to maximize
their rate of gaining valuable information. A cognitive strategy will be
superior to another if it yields more useful information per unit cost.
Foraging juxtaposed with Food Foraging
of prey are always face a recurrent problem of deciding what to eat, and
we assume that its fitness, in terms of reproductive success, is
dependent on energy intake. Metabolic activity of the birds is largely
dependent on its intake. Energy flows into the environment and comes to
be stored in different forms. For that bird, different types of habitat
and prey will yield different amounts of net energy (energetic
profitability) if included in the diet.
the different food-source types will have different distributions over
the environment. This means that the different habitats or prey will
have different access or navigation costs.
example, if the bird decides fish as its diet than it might have to fly
some distance before it encounters a water-source with fish as its
inhabitants. Different species of birds of prey might be compared on
their ability to extract energy from the environment. Birds are better
adapted if they have evolved strategies that solve the problem of
maximizing the amount of energy returned per amount of effort.
flows into the environment and are represented in different types of
external media, such as books, manuscripts, or on-line documents. The
different information sources (or repositories) will have different
profitabilities, in terms of the amount of valuable information returned
per unit cost in processing the source. In addition, the different kinds
of sources will be distributed in the task environment in different
ways. Some will be more prevalent, or less effortful to access, than
others. Conceptually, the optimal information forager is one that best
solves the problem of maximizing the rate of valuable information gained
per unit cost, given the constraints of the task environment.
Information Foraging came into existence
innovation has lead to an explosive growth of recorded information.
growth triggers (and is triggered by) adaptations in human information
technology, since human minds, although growing in number, are limited
in their ability and available time to keep pace. Providing people with
access to more information is not the problem.
Information foraging theory is an approach
to understanding how user strategies and technologies for information
seeking, gathering, and consumption are adapted to the flux of
information in the environment. The framework borrows from biology, and
especially from the field of optimal foraging theory.
The task environment of an information
forager often has a “patchy” structure. Information relevant to a
person’s information needs may reside in piles of documents, file
drawers, bookshelves, libraries, or in various on-line collections.
Often the information forager has to navigate from one information patch
to another—perhaps from one WWW site to another, or from one search
engine result to another. The person is faced with decisions such as the
allocation of time among patch foraging tasks.
Scent and Information Diet
Information foraging often involves
navigating through spaces (physical or virtual) to find high-yield
patches. For instance, imperfect information at intermediate locations
is used by the forager to decide on paths through a library or an
on-line text database to target information. Such intermediate
information has been referred to as “residue”. In keeping with
foraging terminology, we have called this scent. Information
scent is the (imperfect) perception of the value, cost, or access path
of information sources obtained from proximal cues, such as WWW links.
For example, on a Web page, information scent may be delivered by link
descriptors, images, contextual clues, such as preceding headings, or by
page arrangement. Our notion is that the proximal perception of
information scent is used to assess the profitability and prevalence of
information sources. These scent-based assessments inform the decisions
about which items to pursue to maximize the information diet of
the forager. Our protocol analysis methodology is aimed in part at
codifying information scent, and we will analyze the effects of
information scent on WWW behaviors.
Foraging Theory frames the analysis of complex ensembles of cognitive
mechanisms and knowledge that are shaped by information foraging
environments. Information Foraging Theory focuses on understanding
adaptation to current environments. The theory could also provide the
scientific basis from which we might engineer innovations that enrich
the information that people process.
Pirolli, P. and S. K. Card,
1999, Information Foraging, UIR Technical Report, January 1999.
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Stephens, D. W. and Krebs, J. R., 1986, Foraging Theory,
Princeton, N. J.: Princeton University Press.
Furnas, G. W., 1997, Effective view Navigation, CHI ’97,
Human Factors in Computing Systems, pp. 367-374.
S.K., Pirolli, P., Wege, M.V., Morrison, J.B., Reeder, R.W., Schraedley,
P.K., Boshart, J., 2001, Information
Scent as a Driver of Web Behavior Graphs: Results of a Protocol Analysis
Method for Web Usability, CHI 2001, 31 MARCH – 5 APRIL, 498-505.
Bharat, K., &
Broder, A, 1998, Estimating the size and overlap of public Web search
engines, Proceedings of the Seventh International World Wide Web
D. J., 1963, Little science; big science, New York: Columbia
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