Kirsh, David. "Problem solving and situated cognition." In Robbins, P., & Aydede, M. (Eds.). (2009). The Cambridge handbook of situated cognition (pp. 264-306). Cambridge: Cambridge University Press. CHAPTER I 5 Problem Solving and Situated Cognition David Kirsh Introduction exploratory process is not well understood, as it is not always systematic, but various In the course of daily life we solve prob- heuristic search algorithms have been pro- lems often enough that there is a special posed and some experimental support has term to characterize the activity and the been provided for them. right to expect a scientific theory to explain Situated cognition, by contrast, does not its dynamics. The classical view in psychol- have a theory of problem solving to compete ogy is that to solve a problem a subject with the classical view. It offers no com- must frame it by creating an internal rep- putational, neuropsychological, or mathe- resentation of the problem's structure, usu- matical account of the internal processes ally called a problem space. This space is underlying problem cognition. Nor does it an internally generable representation that explain the nature of the control of exter- is mathematically identical to a graph struc- nal processes related to problem solving. ture with nodes and links. The nodes can Partly this is a matter of definition. Prob- be annotated with useful information, and lems are not regarded to be a distinct cate- the whole representation can be distributed gory for empirical and computational analy- over internal and external structures such sis because what counts as a problem varies as symbolic notations on paper or diagrams. from activity to activity. Problems do arise If the representation is distributed across all the time, no matter what we are doing. internal and external structures the sub- But from a situated cognition perspective ject must be able to keep track of activ- these problems should not be understood ity in the distributed structure. Problem as abstractions with a formal structure that solving proceeds as the subject works from may be the same across different activities. an initial state in this mentally supported Each problem is tied to a concrete setting space, actively constructing possible solu- and is resolved by reasoning in situation- tion paths, evaluating them and heuristi- specific ways, making use of the material and cally choosing the best. Control of this cultural resources locally available. What is 264 177 problem sol ving and situated cognition called a problem, therefore, depends on the explain how people solve problems that are discourse of that activity, and so in a sense, is ill defined, which they recognized a large socially constructed. There is no natural kind class of problems to be. called "problem" and no natural kind process To develop their theory they presented called "problem solving" for psychologists to subjects with a collection of games and puz- study. Problem solving is merely a form of zles with unique solutions or solution sets. reasoning that, like all reasoning, is deeply Having a correct answer - a solution set - bound up with the activities and context in is the hallmark of a problem being well which it takes place. Accordingly, the situ- defined. Problems were posed in contexts ational approach highlights those aspects of in which the experimenter could be sure problem solving that reveal how much the subjects had a clear understanding of what machinery of inference, computation, and they had to solve. Games and puzzles were representation is embedded in the social, chosen because they are self-contained; it is cultural, and material aspects of situations. assumed that no special knowledge outside This critical approach to problem solving of what is provided is needed to solve them. is what I shall present first. In Part 11 discuss These sorts of problems have a strict defi- the assumptions behind the classical psycho- nition of allowable actions (you move your logical theory. In Part 2 I present the major pawn like this), the states these actions cause objections raised by those believing that cog- (the board enters this configuration), and a nition must be understood in an embodied, strict definition of when the game or puzzle interactive, and situated way, and not pri- has been solved, won, or successfully com- marily as a cognitive process of searching pleted (opponent's king is captured). It was through mental or abstract representations. assumed that subjects who read the prob- There is a tendency in the situated cogni- lem would be able to understand these ele- tion literature to be dismissive of the clas- ments and create their internal representa- sical view without first acknowledging its tion. Such problems are both well defined flexibility and sophistication. Accordingly, I and knowledge lean, as "everything that the present the classical account in its best form subject needs to know to perform the task in an effort to appreciate what parts may be is presented in the instructions" (VanLehn, useful in a more situated theory. In Part 3 I 1989, p. 528). No special training or back- collect pieces from both accounts, situated ground knowledge is required. and classical, to move on to sketch a more positive theory - or at least provide desider- ata for such a theory - though only frag- 2. Task Environment ments of such a view can be presented here. In the classical theory, the terms problem and task are interchangeable. Newell and PART 1: THE CLASSICAL THEORY Simon introduced the expression task envi- ronment to designate an abstract structure 1. Newell and Simon's Theory that corresponds to a problem. It is called an environment because subjects who improve In an extensive collection of papers and task performance are assumed to be adapt- books, Herbert Simon, often with Allen ing their behavior to some sort of environ- Newell, presented a clear statement of the mental constraints, the fundamental struc- now-classical approach to problem solv- ture of the problem. It is abstract because ing (see, among others, Newell & Simon, the same task environment can be instan- 1972). Mindful that science regularly pro- tiated in very different ways. In chess, for ceeds from idealization, Simon and Newell example, the task environment is the same worked from the assumption that a the- whether the pieces are made of wood or sil- ory based on how people solve well-defined ver or are displayed on a computer screen. problems can be stretched or augmented to Any differences arising because agents need DAVID KIRSH to interact differently in different physical nomenon. The same would apply to other contexts are irrelevant. It does not matter things nonexperts do when they play, SUcj1 whether an agent moves pieces by hand, as putting a finger on a piece, trying |f by mouse movements, by requesting some- possible actions on the board, using pencil one else to make the move for them, or and paper, talking to oneself, or consulting by writing down symbols and sending a a book (if allowed at all). All are assumed description of their move by mail. Issues irrelevant to task performance. They may associated with solving these movement or occur while a subject is working on a prob- communication subtasks belong to a differ- lem, or while playing chess, but, according ent problem. to the classical account, they are not liter- A task environment, accordingly, delin- ally part of problem-solving activity. This is eates the core task. It specifies an under- obviously a point of dispute for situation- alists, as many of these actions are regularly lying structure that determines the rele- observed during play, and they may critically vant effects of every relevant action that a affect the success of an agent. given agent can perform. This has the effect that if two agents have different capacities for action they face different task environ- ments. When four-legged creatures confront 3. Problem Space an obstacle, they face a different locomo- tion problem than two-legged creatures, and Task environments are differentiated from both problems are different from the loco- problem spaces, the representation sub- motion problem the obstruction poses to jects are assumed to mentally construct a snake. Thus, two agents operating in the when they understand a task correctly. This same physical environment, each facing the problem-space representation might be dis- same objective - get from atob- may face tributed over external resources. It encodes different task environments because of their the following: different capacities. Their optimal path may be different. Moreover, of all the actions a | The current state of the problem. At the creature or subject can perform, the only beginning this is the initial state. ones that count as task relevant are the ones • A representation of the goal state or con- that can, in principle, bring it closer to or far- dition - though this might be a procedure ther from an environmental state meeting or test for recognizing when the goal has the goal condition. It is assumed that dif- been reached, rather than a declarative ferences in expertise and intellectual ability statement of the goal. affect search and reasoning rather than the I Constraints determining allowable moves definition of the task itself. and states, hence the nodes and allow- Task environments are theoretical projec- able links of the space I these too tions that let researchers interpret problem- may be specified implicitly in procedures solving activity in concrete situations. They for generating all and only legal moves identify what counts as a move in a problem rather than explicitly in declarative state- (for a given agent). As such, they impose ments. a powerful filter over the way a researcher • Optionally, other representations that interprets subjects' actions.