Planning

What is Planning?

Prospective memory Opens in new window involves remembering Opens in new window what to do and when to do it. Planning and mental rehearsal are concerned with how to do it.

As defined by Hayes-Roth and Hayes (1979),

According to Battman (1987, p.4),

In everyday life, people spend a lot of time planning how to do things. This is particularly true when a prospective task Opens in new window is a novel or complex one involving a sequence of actions, and when decisions have to be taken about which actions will produce the best results.

People plan journeys and holidays; what to buy for dinner and what to plan in the garden; how to play a hand of bridge or behave at a job interview.

Those actions that are unplanned are very simple or very routine ones, automatic, unconscious actions or purely impulsive actions. For most people a high proportion of their daily activities involve some degree of planning.

Planning is also a type of problem-solving Opens in new window by mental simulation, envisaging the circumstances and running through possible actions, evaluating the consequences, and selecting the optimal actions and the optimal order for executing them.

Planning depends on memory. Knowledge derived from past experience and stored in long-term memory must be retrieved and used in formulating possible plans, and in constructing representations of hypothetical events. A working memory buffer store is needed to hold tentative or incomplete plans while these are being evaluated or revised.

Individual Differences in Planning

It is common knowledge that people differ in the amount of planning they habitually do. We all know people who rush into things without stopping to think at all, and others who obsessively think through every detail before embarking on a course of action.

There has been little formal investigation of these differences so far. Giambra (1979) analyzed the content of daydreams (defined as thought unrelated to the current tasks), and found that for all age groups the majority of daydreams were of the type he called “problem-solving Opens in new window” and involved planning future activities.

Young males were the exception to this generalization: They had more daydreams of love and sex than of problem-solving. Females of all ages had more problem-solving daydreams than males.

This finding has also emerged from a questionnaire used in a pilot study by Cohen and Faulkner (unpublished). Females reported spending more time on mental planning; they planned in more detail, and formulated more alternative plans in case of difficulties.

Elderly people also reported more planning than young people. The reasons underlying these differences are not clear, but probably include personality, level of anxiety, work load, and the importance of efficient performance.

The Traveling Salesman Task

Battman (1987) studied the planning involved in the “traveling salesman problem”. He was interested primarily in the function of planning and also in individual differences in planning.

Battman argued that planning entails an investment of time and effort. It is therefore only cost-effective if it improves efficiency and/or reduces anxiety in the execution phase. But planning is not always helpful. If the plan is inadequate, or if circumstances change, it may be a positive disadvantage.

Battman compared the performance of two groups of subjects in a version of the traveling salesman task.

Subjects had to act as chain store supervisors, visiting 10 stores in one day. Three of the visits had to be made at pre-arranged times, plus or minus 10 minutes.

Subjects had to make decisions about marketing or finance at each store. They had access to a map and information about average between-store travel times and the average time needed to handle a problem within a store.

In addition, they could change any of the appointment times, provided this was done at least 25 minutes beforehand. Arriving early for an appointment meant wasting time; arriving late entailed making a second visit.

One group of subjects were instructed to plan before beginning the task. They could fix intermediate goals and write out a schedule of visits. The other group were not instructed to plan ahead.

The subjects with plans performed more efficiently. They kept more appointments punctually, completed more visits, spent less time driving between stores, and made more use of the ability to change appointments.

As well as these indices of efficiency, level of stress was monitored during performance. The findings differed according to the intelligence of the subjects. High-IQ subjects who planned were more stressed on the first trial, but benefited on later trials. Planning was cost-effective for them because it improved efficiency and reduced anxiety.

For low-IQ subjects planning brought no reduction in anxiety. Planning did increase their efficiency, but keeping to the plan was effortful, and a high level of stress was maintained.

Battman concluded that generating and executing a play can, in some circumstances, be more demanding than simply responding in an ad hoc way and “making it up as you go along”. Most of us can probably think of people we know who are meticulous planners, but who clearly suffer a good deal of agitation in trying to execute these plans.

Planning Errands

A detailed study of planning by Hayes-Roth and Hayes-Roth (1979) used verbal protocols to study the way people plan a day’s errands. The subjects’ task was to produce a plan for completing as many as possible of the errands listed below, moving around the hypothetical town shown in the map (Figure X-1).

Figure X-1. The town map for the errand planning task | Source: ResearchGate Opens in new window.

“You have just finished working out at the health club. It is 11.00 and you can plan the rest of your day as you like. However, you must pick up your car from the Maple Street parking garage by 5.30 and then head home. You’d also like to see a movie today, if possible. Show times at both movie theatres are 1.00, 3.00, and 5.00. Both movies are on your ‘must see’ list, but go to whichever one fits most conveniently into your plan. Your other errands are as follows:

• pick up medicine for your dog at the vet
• buy a fan belt for your refrigerator at the appliance store
• check out two of the three luxury apartments
• meet a friend for lunch at one of the restaurants
• buy a toy for your dog at the pet store
• pick up your watch at the watch repair shop
• special order a book at the bookstore
• buy fresh vegetables at the grocery store
• buy a gardening magazine at the newsstand
• go to the florist to send flowers to a friend in hospital.”

This typical subject started by defining the goal and tasks and classifying errands as high-priority or low-priority. He begins sequencing the errands from the start point, forming clusters of errands based on priority and on adjacency.

There are frequent revisions of the plan, and at a later stage, some sequencing backward in time from the final errand (picking up the car at 5.30).

The mental simulation of one stage of the plan guides the later stages, and consists in mentally timing the actions and inferring the consequences. Planning occurs at different levels of abstraction, sometimes involving specific items and sometimes higher-order clusters.

Hayes-Roth and Hayes-Roth noted that planning was opportunistic. The subject did not formulate an overall global plan and then proceed to fill in the stages by successive refinements, but jumped about between levels with many shifts and changes.

Instead of being controlled in a top-down direction by higher-order principles and pre-set goals, the plan was under multidirectional control, many decisions being influenced on a moment-to-moment basis by new facts that came to light as planning proceeded.

Planning was incremental, with tentative decisions becoming gradually firmer, and alternative plans were considered in parallel. The cognitive model they formulated to represent these aspects of the planning process included a working memory buffer, which they call the blackboard, where different forms of knowledge interact.

The different kinds of knowledge include:

1. Knowledge of the overall task (the metaplan).
2. A set of possible actions, procedures for implementing them and outcomes (plans).
3. A list of desirable attributes (such as quick, adjacent) for these plans (plan-abstractions).
4. A knowledge base of specific data about errand routes and locations.

The model also has an executive for taking decisions and for allocation of resources. A computer simulation of this model produced a protocol broadly similar to that produced by a human subject, but the computer’s plan was more feasible. It sacrificed more of the low-priority errands and, unlike the human subject’s plan, it could have been completed in the available time.

In the errand-planning task the problem lies in selecting and ordering actions. The constraints are mainly of time and distance and the task involves a number of goals that are interdependent, a knowledge base that is equivalent to long-term memory, and the blackboard for carrying out evaluations and decision processes that is equivalent to working memory.