3a. finding information from the Environment

Section 3a : Ways of meeting the cognitive needs 1 : environment

Building up behavioural complexity from a cognitive processing element

Lisanne Bainbridge

A person using an 'interface', of displays and controls between them and the process they are controlling, is not just reacting to signals from one location with their hands already on the response buttons, as in many laboratory psychology experiments.

Figure 3.1 shows the interface between the furnace power supply controller and (the simulation of) the process he was controlling. This study was done in the mid-60s, long before the advent of small computers or graphic screens. There was also a teleprinter, which gave more detailed factual information about some events on the process.

Figure 3a.1. The operator’s interface in the furnace power control task, Bainbridge et al (1968) Figure 1.

Five furnaces - power usage by each in lower row of dials.

Circle of signal lights shows which stage each furnace is in.

Controls to alter power usage are most accessible, at the front of the lower control panel.

There were two ways in which the information sources might attract the operator’s attention and override his thinking :

- he might see the flash of a light position change or a position change on a dial-and-pointer display, when a furnace changed from one state to another,

- the teleprinter was noisy, and loud noises automatically attract attention.

Otherwise he had to direct his attention to the source of information he needed.

An operator needs to know how to use this interface :

- where to look for the information they need, and how to interpret it,

- where to reach to an action they want to make, and how to make it.

Alternative ways of meeting cognitive needs

Figure 2.3 in the previous section showed how the section of thinking about the furnace power control task reported in Table 2.1 might find the information needed from either the environment - the process interface and the instruction booklet, or from simple calculations - by further cognitive processing, meeting the cognitive need by using a subsidiary 'routine'. Or, as in Tables 2.2 and 2.3, the information an operator needs may be in his knowledge base.

Expanding on that : how in general may the information wanted to meet a cognitive goal/ need be found? There are four general sources :

- raw unprocessed data, direct from the environment. Some brief notes on that in this Section 3a.

There may be many sensory sources available by attending to the environment : by listening, by looking, smelling, or by reaching and feeling in the appropriate direction. In process control, an operator may attend to an interface, instructions, or other people, as well as directly to the device being controlled, perhaps leaving the control room to look/ listen to/ touch/ feel/ smell direct at the plant, or sending/ contacting someone else who can do so.

- data from a knowledge base, such as the reasons why a specific alarm may go off. There are two short Sections on this, 3b and 3d, as it is best discussed both before and after discussing 'routines’.

- in complex tasks : more often - the information needed is found by doing some thinking :

- - by doing some cognitive processing. More on that in the next Section 3b, which discusses issues when several cognitive elements are needed together to make a method for finding the information wanted, a 'routine'.

- - by reference to non-local working storage, to the stored results of previous 'routines', as discussed in Section 4 also 5-6.

There often isn’t a fixed method of finding any given information, except in highly over-practised skills. The methods may be used interchangeably, depending on circumstances. For example someone may want to know the value of x. If it isn’t on the interface, in support materials, or in their knowledge base - then they may know how to find it (a 'routine') or ask someone else for it. Which method for finding the information is used depends on the environment, the current situation, and the experience of the person involved. Examples are given in this whole Section 3, and the issue of choosing which method is best to use in a given context is discussed more fully in Section 7.

The stepped arrow in the cognitive processing diagrams implies transfer of control from the originating cognitive need to visual or other sensory search and interpretation processes (which might be done in parallel). There may be no problem with obtaining the external information : the source and interpretation of information in the environment may be obvious or familiar. Or finding and interpreting the information, before it can be used to meet the cognitive need, may themselves involve cognitive processes, which control the search, interpret what is found, and translate it into a form usable by the originating cognitive need. After practice, finding this information can range from simply looking in a known stable direction (a perceptual-motor skill) to (knowing how to) look up data in a reference source.

The environment and interface

This is a very brief section, as interface and support material design is not the main focus of this review. But I have written about some of the issues elsewhere, so here are some links.

The major focus of classical interface human factors/ ergonomics is on minimising the need for any additional cognitive processing or movements to acquire data from external sources and to understand the interface and support materials, before the interface information can be used in task-related cognitive processing.

For more on the cognitive processes underlying using an interface, see the first part of the review of processes underlying human performance.

Support material design has not been much discussed in my papers, but there are comments on the problem solving which may be needed in understanding written instructions in Bainbridge, 1989.

And all these ways of finding the information mean the link between the 'goal' of finding out what is happening and how that finding out is done must be flexible, see Section 7.

For example if information is difficult to obtain from the interface or instructions, this could affect how likely someone is to do a method of thinking which uses that information.

This focus of this review is on the task-related thinking, not the thinking needed to understand the environmental sources, though actually they may be closely interrelated - see the short excerpts in the previous Section (Tables 2,2 and 2.3 in Section 2) from nuclear power plant fault diagnosis.

Also, in the current era, computer generated displays are possible. So the interface can display not just values from transducers on the plant, but also ready-processed versions of combined data, such as an overview of the plant state.

But this may not be optimal if :

- the operator uses the data from which the display has been generated in different ways in different parts of the task.

- it is the operator’s thinking in building up their own overview which makes the information most readily available to later task thinking, see Sections 4-6.

So it is possible that pre-processed displays may make a task more difficult.

There's some discussion of such issues in the paper on multi-plexed displays.

Main points in Section 3.a

- getting information directly from the environment (such as from the interface) should be the easiest way of getting the information needed in task thinking. Classic ergonomics/ human factors tries to minimise the physical and mental effort needed.

- understanding the interface and support materials may themselves need cognitive processing, though that is not the focus of this review.

- there is not always a clear distinction between interface-related cognitive processing and task-related cognitive processing.

- computer generated displays of combined data may need to be designed with care.

- cognitive needs may also be met from the working storage associated with other cognitive needs (Section 3c), or from a knowledge base (Section 3b and 3d).

Access to other papers on this site via Home page

In this review, there are 3 main groups of topics.

1. Introduction.

Basic element, sources of data which meet cognitive needs.

2. The cognitive processing element.

Meeting an information need :

3a. by finding it in the environment.

3b. from a stored knowledge base.

3c. by working through a 'routine',

or referring to the result of using a routine elsewhere.

3d. more on knowledge bases.

Choosing what to do.