The water-jug problem

Another problem with heuristics is that they become so deeply remembered in our minds after having dealt with a similar problem, that most subjects are not able to ignore the heuristic to solve a different problem quicker. An example of this is the monster-globe problems investigated by Simon& Hayes(1974). This is an isomorphic problem to the Tower of Hanoi problem with the same problem space.

Since isomorphism ensured that both the problems had the same problem space features such as size and minimum solution path length, the experiment could focus on the difference presentations of the problem can make.

Subjects had difficulty solving this problem even though they already had experience with the Tower of Hanoi problem. They were unable to solve the problem as the problem was presented to them in a different way. This hindered their decision making.

The water-jug problem is similar as prior experience with a similar problem caused difficulty for subjects solving the problem. The subjects were first presented with several problems that they solved by one method.

They were then presented with another problem which could be solved using a different method which would save them time and effort, yet most subjects did not follow that method as they automatically used the first method.

This experiment showed that heuristics are hard to unlearn thus they make hinder problem solving as they prevent the subject from finding an easier way to reach the solution. On the one hand, heuristics emphasise the mind’s ability to make a selective judgement based on given information to solve a problem or make a decision faster.

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Unlike computers, the mind is constrained in its capacity to look at all possible solutions and if it did, it would take a lot longer to make a decision. Thus the mind is able to create shortcuts in order to save time.

Heuristics are a prime example of this as the mind uses heuristics in order to find these shortcuts. However, heuristics also demonstrate that there are limitations to our working memory. Atwood&Polson(1976) found that subjects only look ahead to a depth of one move through the water-jug experiments. They use the loop avoidance heuristic to avoid moves that they believe would return them to previously visited states, even though it might be easier to reach the solution by going back.

Thus they are unable to look ahead more than one move. However, they also found that subjects used the means-end analysis as they compared their actual state to the goal state, which is helpful in decision making. After identifying the difference between the two states, they would compare moves to see which would bring them closer to the goal state, yet again demonstrating the mind’s inability to accept that not all moves towards a goal would be a shortcut to it but rather that the goal could be reached by moving away from it.

They discovered that there were definite limitations in the mind to offer a greater number of possible alternate moves that can be stored in the working memory. This could be adjusted by transfering information into the long term memory. A demonstration of this is proffessional chess players. Because the information they need to make a move while playing chess is stored in the long term memory due to a great number of past experiences with similar problems, they are able to present a greater number of moves than an average human.

However, as Atwood, Masson&Polson found in 1980, there are greater limitations to our decision making ability than just a limited working memory. In an experiment to prove this theory, they presented the subjects with a problem and divided them in groups. They then presented all the possible moves to reach the solution in order to avoid overloading working memory. By doing this they hoped that there would be more space for more long term planning. However most subjects used the moves to avoid going back in the problem rather than find a quicker solution by more planning.

There was no massive improvement in planning to find the solution. This experiment demonstrates that our mind is usually not efficient in long term planning. Overall, although heuristics can have a positive effect on our decision making and problem solving, they can also hinder decision making as they are too based on assumptions. Heuristics show that our mind takes the most logical shortcuts to solving a problem to save time and effort, although it is limited in its capacity to always find the right solution.

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The water-jug problem. (2020, Jun 02). Retrieved from

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