November 2005 / Vol. 55 No. 11 • BioScience 967Thinking collectively about complex problems requires crossing boundaries both horizontally (acrossdisciplines) and vertically (across experts, policymakers, prac-titioners, and the public) (Klein 2004). Although the debateson climate change discussed elsewhere in this issue (Norgaardand Baer 2005a) exemplify strong boundary crossing in bothdimensions, most scholars, when they venture into collectivethinking, may begin with collaborations that stress the moreacademic, horizontal crossings. Much of the current inter-disciplinary research on the environment is probably of thiskind, and it also tends to have a smaller geographical focusthan ongoing debates on climate change.Without gainsayingthe need for crossings in the vertical dimension, an analysisof interdisciplinarity in this limited context can provide use-ful insights into the problems generated by researchers’ dis-ciplinary training and conditioning. In the context of workingwith a team of scholars from several disciplines on a regional-scale project, we explore the practical difficulties of partici-pating in interdisciplinary research, drawing on our ownexperience in the fields of forestry, biodiversity, and hydrol-ogy, as well as other sources.When scientists come together in such teams, it is usuallyaround some shared interest, such as conserving biological di-versity or improving the food security of the poor. Theseshared interests, however, do not translate into a researchplan with predetermined bridges between the disciplines.Problems may show up early. When engaging with their col-leagues in other fields, scientists typically find that their col-leagues define the problem quite differently or seek differenttypes of answers. For a few, this is an exciting discovery thatenergizes them to understand these differences. Many, how-ever, decide that it takes too much effort to communicate andshare knowledge within such a disparate group, and happilyretreat to their own special fields, where all the participantsuse the same models of analysis, are comfortable with the as-sumptions they share as a group, and consequently “know”the same things. The purpose of this article is to help re-searchers who do choose to engage in interdisciplinary workby identifying the barriers to interdisciplinarity in a way thatmakes them easier to overcome. At the outset, we would liketo point out that the term “discipline” is a little too slipperyfor a thorough analysis of the types of barriers that need tobe surmounted (box 1). But given that most of us are broughtup with these disciplinary labels, we will continue to use themajor disciplinary categories or blocks (the “natural” and the“social” sciences) as a starting point, identifying the incon-sistencies and subtleties as we go along. We should also men-tion that, for the sake of brevity, we use the term“interdisciplinarity” loosely to describe all types of crossingsbetween or among disciplines, glossing over the subtle dif-ferences between multi-, inter-, and transdisciplinarity thatare highlighted in more elaborate discussions on this subject(see, e.g., Kockelmans 1979).Sharachchandra Lélé (e-mail: [email protected]) works at the Centre for Interdisciplinary Studies in Environment and Development, Bangalore, India.Richard B. Norgaard (e-mail: [email protected]) works in the Energy and Resources Group, University of California, Berkeley, CA 94720. © 2005 American Institute of Biological Sciences.Practicing InterdisciplinaritySHARACHCHANDRA LÉLÉ AND RICHARD B. NORGAARDWe explore the practical difficulties of interdisciplinary research in the context of a regional- or local-scale project. We posit four barriers to interdisciplinarity that are common across many disciplines and draw on our own experience and on other sources to explore how these barriers aremanifested. Values enter into scientific theories and data collection through scientists’ hidden assumptions about disciplines other than their own, throughthe differences between quantitative and interpretive social sciences, and through roadblocks created by the organization of academia and the relationship between academics and the larger society. Participants in interdisciplinary projects need to be self-reflective about the value judgments embedded in their choice of variables and models. They should identify and use a core set of shared concerns to motivate the effort, be willing to respect and to learn more about the “other,” be able to work with new models and alternative taxonomies, and allow for plurality and incompleteness.Keywords: epistemology, sociology of science, interdisciplinary research, environmental problemsSpecial Roundtable SectionWe begin by outlining a common set of barriers that schol-ars from different disciplines are likely to encounter when theycome together to work on a project. Next, we discuss whichbarriers are most important and what shape they take whenworking within the natural sciences. Third, we address themore difficult problems of working across the natural and so-cial sciences. One of the reasons it is so difficult for naturalscientists to work with social scientists is because the latterthemselves are divided, as we explain in more detail below.Barriers to interdisciplinarityWe identified four major types of barrier to interdisciplinar-ity. First, there is the problem of values being embedded in alltypes of inquiry and at all stages: in the choice of questions,theoretical positions, variables, and style of research. But cer-tainly natural scientists, and even social ones, are loath to ac-knowledge the presence of value judgments in their work.Furthermore, in the context of contentious social issues (e.g.,sustainable development), decisionmakers call on scientiststo provide “objective” advice, making such acknowledgmenteven more difficult. Consequently, the collective judgment re-quired in interdisciplinary research is especially difficult. It isfraught with the possibility that scientists will “talk past eachother” because of the ways in which the disciplines assert eth-ical neutrality and cast a blind eye to their own normative positions.Second, researchers in different disciplines may study thesame phenomenon but differ in their theories or explanatorymodels (and underlying assumptions). In the case of complexphenomena, it is not easy to prove the superiority of one the-ory over another in a particular case.