INFORMATION PROCESSING

Information processing is the process of receiving information through the senses, analysing it and making it meaningful.

1. AN INFORMATION PROCESSING MODEL:

Information processing can be represented as a model. This captures the main elements of the process, from receipt of information via the senses (stimuli), to outputs such as decision making and actions.

1.1. Sensory receptors and sensory stores:

Physical stimuli are received via the sensory receptors (eyes, ears, etc.) and stored for a very brief period of time in sensory stores (sensory memory). Visual information is stored for up to half a second in iconic memory and sounds are stored for slightly longer (up to 2 seconds) in echoic memory.

1.2. Attention and perception:

Having detected information, our mental resources are concentrated on specific elements, this is attention.

Although attention can move very quickly from one item to another, it can only deal with one item at a time. Attention can take the form of:

  • selective attention,

  • divided attention,

  • focused attention

  • sustained attention.

a) Selective attention occurs when a person is monitoring several sources of input, with greater attention being given to one or more sources which appear more important. A person can be consciously attending to one source whilst still sampling other sources in the background.

Distraction is the negative side of selective attention.

b) Divided attention is common in most work situations, where people are required to do more than one thing at the same time. Usually, one task suffers at the expense of the other, more so if they are similar in nature. This type of situation is also sometimes referred to as time sharing.

c) Focused attention is merely the skill of focusing one's attention upon a single source and avoiding distraction.

d)Sustained attention as its name implies, refers to the ability to maintain attention and remain alert over long periods of time, often on one task. Most of the research has been carried out in connection with monitoring radar displays, but there is also associated research which has concentrated upon inspection tasks.

  • Note:

    Attention is influenced by arousal level and stress. This can improve attention or damage it depending on the circumstances. Attention can be thought of as the concentration of mental effort on sensory or mental events.

    Perception involves the organization and interpretation of sensory data in order to make it meaningful, discarding non-relevant data, i.e. transforming data into information. Perception is a highly sophisticated mechanism and requires existing knowledge and experience to know what data to keep and what to discard, and how to associate the data in a meaningful manner.

1.3. Decision making :

Having recognized coherent information from the stimuli reaching our senses, a course of action has to be decided upon. In other words decision making occurs. This may range from deciding to do nothing, to deciding to act immediately in a very specific manner.

A fire alarm bell, for instance, may trigger a well-trained sequence of actions without further thought (i.e. evacuate); alternatively, an unfamiliar siren may require further information to be gathered before an appropriate course of action can be initiated.

We are not usually fully aware of the processes and information which we use to make a decision.

tools can be used to assist the process of making a decision. For instance, in aircraft maintenance engineering, many documents (e.g. maintenance manuals, fault diagnosis manuals), and procedures are available to supplement the basic decision making skills of the individual.

Thus, good decisions are based on knowledge supplemented by written information and procedures, analysis of observed symptoms, performance indications, etc. It can be dangerous to believe that existing knowledge and prior experience will always be sufficient in every situation as will be shown in the section entitled ‘Information Processing Limitations'.

Finally, once a decision has been made, an appropriate action can be carried out. Our senses receive feedback of this and its result. This helps to improve knowledge and refine future judgment by learning from experience.

Perception can be defined as the process of assembling sensations into a useable mental representation of the world. Perception creates faces, melodies, works of art, illusions etc. out of the raw material of sensation.

  • Examples of the perceptual process:

    The image formed on the retina is inverted and two dimensional, yet we see the world the right way up and in three dimensions;

    If the head is turned, the eyes detect a constantly changing pattern of images, yet we perceive things around us to have a set location, rather than move chaotically.

Decision making is the generation of alternative courses of action based on available information, knowledge, prior experience, expectation, context, goals, etc. and selecting one preferred option. It is also described as thinking, problem solving and judgment.

1.4. Motor programmes:

If a task is performed often enough, it may eventually become automatic and the required skills and actions are stored in long term memory. These are known as motor programmes and are ingrained routines that have been established through practice.

The use of a motor programme reduces the load on the central decision maker. An often quoted example is that of driving a car: at first, each individual action such as gear changing is demanding, but eventually the separate actions are combined into a motor programme and can be performed with little or no awareness.

These motor programmes allow us to carry out simultaneous activities, such as having a conversation whilst driving.

2. SITUATION AWARENESS:

The process of attention, perception and judgment should result in awareness of the current situation.

Situation awareness has traditionally been used in the context of the flight deck to describe the pilot's awareness of what is going on around him, e.g. where he is geographically, his orientation in space, what mode the aircraft is in, etc.

In the maintenance engineering context, it refers to:

  • the perception of important elements, e.g. seeing loose bolts or missing parts, hearing information passed verbally;

  • the comprehension of their meaning, e.g. why is it like this? Is this how it should be? Situation awareness is the synthesis of an accurate and up-to-date 'mental model' of one's environment and state, and the ability to use this to make predictions of possible future states.

  • the projection of their status into the future, e.g. future effects on safety, schedule, airworthiness.

As with decision making, feedback improves situation awareness by informing us of the accuracy of our mental models and their predictive power. The ability to project system status backward, to determine what events may have led to an observed system state, is also very important in aircraft maintenance engineering, as it allows effective fault finding and diagnostic behavior.

Situation awareness for the aircraft maintenance engineer can be summarized as:

  • the status of the system the engineer is working on;

  • the relationship between the reported defect and the intended rectification;

  • the possible effect on this work on other systems;

  • the effect of this work on that being done by others and the effect of their work on this work.

3. INFORMATION PROCESSING LIMITATIONS:

The basic elements of human information processing have now been explored. It is important to appreciate that these elements have limitations. As a consequence, the aircraft engineer, like other skilled professionals, requires support such as reference to written material (e.g. manuals).