Thought processes/Google(Problem Space/ July 22, 2010)
---------------------------------------------------------------------------"Cogito ergo sum" (I think therefore I am). These words of Descartes sum up the importance of thought processes in humans and probably the most important reason we differ from animals. Although animals retrieve and store information, there is little evidence to suggest that they can use it in quite the same way as humans. Humans, on the other hand, are able to use information to reason and solve problems, even when the information is partial or unavailable.
Thinking can be categorized into reasoning and problem solving. Although these are not distinct they are helpful in clarifying the processes involved.
Reasoning
Reasoning is the process by which we use the knowledge we have to draw conclusions or infer something we know about the domain of interest. Reasoning is classified as being deductive, inductive or abductive. Deductive reasoning involves deciding what must be true given the rules of logic and some starting set of facts(premises). Inductive reasoning involves deciding what is likely to be true given some starting set of beliefs or observations.
Deductive reasoning
Deductive reasoning derives the logically necessary conclusion from the given premises. It is important to note that it can lead to a logical conclusion which conflicts with our knowledge of the world.
For example,
If it is raining then the ground is dry.
It is raining.
Therefore the ground is dry.
is a perfectly valid deduction ! Deductive reasoning is therefore often misapplied. Human deduction is at its poorest when truth and validity clash. This is because people bring their knowledge of the real world into the reasoning process as it allows them to takeshort cuts which make information processing more efficient.
Inductive reasoning
Induction is generalizing from cases we have seen to infer information about cases we haven't. For instance, if all the dogs that we have seen are white, we may infer that all dogs are white in colour. This is disproved when we see a black dog ! In the absence of counter examples, all that we can do is gather evidence to support our inductive inference. In spite of its unreliablity, induction is a useful process which we use constantly in learning about our environment.
Abductive reasoning
Abduction reasons from a fact to the action that caused it. This is the method we use to derive explanations for the events we observe. This kind of reasoning, although useful, can lead to unreliability as an action preceding an event can be wrongly attributed as the cause of the event.
Problem solving
Problem solving is the process of finding a solution to an unfamiliar task, using the knowledge we have. There are a number of different views of how people solve problems. We shall consider two of the more recent and influential views: Gestalt theory and the problem space theory.
Gestalt theory
Gestalt theory claims that problem solving is productive and reproductive. Reproductive problem solving draws on previous experiences whereas productive problem solving involves insight and restructuring of the problem. Reproductive problem solving could be a hindrance to finding a solution, since a person may fixate on the known aspects of a problem and so be unable to see novel interpretations that might lead to a solution.
A well known example of this is Maier's `pendulum problem'. The problem was to tie together pieces of string hanging from the ceiling. However , they were far too apart to catch hold of both at once. The room was full of other objects including pliers, poles and extensions. Although various solutions were proposed by participants, few chose to use the weight of the pliers as a pendulum to swing the strings together. However, when the experimenter brushed against the string, setting it in motion, a lot of participants came up with the idea. This can be interpreted as an example of productive restructuring. This experiment also illustrates fixation: participants were unable to see any meothd beyond the use of a pair of pliers.
The illustration above shows another example of Gestalt theory. In the picture above (I) naturally can be perceived as a collection of 36 points, like one is supposed to do in picture (II), but everybody is well disposed to see six columns of points, while in picture (III) one tends to see six rows. The way how a Gestalt (meaningful whole) arises from a set of simplexes is one of the main subjects explored by Gestalt Theory.
However, Gestalt theory does not provide sufficient evidence or structure to support its theories.
Problem space theory
The problem space theory was proposed by Newell and Simon. The theory says that problem solving centers around the problem space. This space comprises of problem states which can be generated using legal transition operators.
For example, imagine you are reorganizing your office and you want to move the desk from one end to another. The two different states are represented by the locations of the desk. A number of operators can be applied to move these things: they can be carried, pushed, dragged etc. In order to ease the transition between the states, you have a new sub-goal: to make the desk light. These may involve operators such as removing drawers and so on.
Within the problem space framework, experience allows us to solve problems more easily since we can structure the problem space appropriately and choose operators efficiently.
Analogy in problem solving
People solve novel problems by mapping knowledge in a similar known domain, to it. For instance, to destroy malignant tumour it is essential to fire low intensity rays from all sides, as high intensity rays can damage heathy tissues. An analogous case is that of attacking a fortress. However, people miss analogous information unless it is semantically close to the problem domain.
Skill acquisition
Skills in a given problem area differentiate the novice from the expert. A commonly studied domain is chess playing. It is particularly suitable since it lends itself to representation in terms of problem space thoery, in which the intial board configuration and the final position constitute the states while the moves appeared as transition operators. Masters took lesser time than novices to react to a situtation and produced better moves. This is largely because chess masters remember board configurations and good moves associated with them. They can chunk the board configuration in order to hold it in short-term memory.
Skilled behavior becomes automatic over a period of time. Experts tend to mentally rehearse their actions in order to identify exactly what they do. Although such skilled behavior is efficient it may cause errors when the context of the activity changes.
Individual differences
The psychological principles and properties that have been discussed apply to the majority of people. However, there are individual differences which affect a small percentage. The differences may be long term such as sex, physical capabilities and individual capabilities. Others are for a shorter duration and may include the effects of stress or failure on the user. Still others may change through time such as age. These differences should be taken into account in interface designs to enusre that a greater population of users is benefited.
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