Task loading

task load indicates the degree of difficulty experienced when performing a task, and task loading describes the accumulation of tasks that are necessary to perform an operation. A light task loading can be managed by the operator with capacity to spare in case of contingencies.

In underwater diving, task loading increases the risk of failure by the diver to undertake some key basic function which would normally be routine for safety underwater.A heavy task loading may overwhelm the diver if something does not go according to plan. This is particularly a problem in scuba diving, where the breathing gas supply is limited and delays may cause decompression obligations. The same workload may be a light task loading to a skilled diver with considerable experience of all the component tasks, and heavy task loading for a diver with little experience of some of the tasks.

Task loads may be measured and compared. NASA uses six sub-scales in their task load rating procedure. Three of these relate to the demands on the subject and the other three to interactions between subject and task. Ratings contain a large personal component and may vary considerably between subjects, and over time as experience is gained.

1. Mental Demands: How much mental and perceptual effort is required;
2. Physical Demands: How much physical effort is required;
3. Temporal Demands: How much time pressure the subject feels;
4. Own Performance: Rating of how successfully the task was performed;
5. Effort: Rating of how much effort was put into the task; and
6. Frustration: Rating of how frustrating or satisfying the task was to perform.

Common examples

Common examples of activities which can contribute to high task loading are:

• underwater photography or videography
• underwater search and recovery
• underwater mapping
• diving in environments requiring use lights or guide reels (such as night diving, wreck diving and cave diving) or other additional equipment
• use of dry suits
• driving a diver propulsion vehicle (DPV)
• diving in cold water
• breathing narcotic gas mixture indirectly affects task loading by reducing the capacity to manage the tasks effectively
• use of a rebreather, particularly in the event of a malfunction.

Task loading represents an elevated risk when a new activity is undertaken by an inexperienced diver. A diver learning how to use a dry suit, or starting underwater photography, will need to dedicate considerably more attention to the proper functioning of the new and unfamiliar piece of equipment which leads to the elevated risk of neglect of other responsibilities. Those risks will normally diminish with experience.

Common examples of routine functions that can be neglected as a result of task loading are:

• monitoring air supply properly
• maintaining buddy contact
• maintaining proper buoyancy
• monitoring depth and time to avoid no-decompression limits, or remain within planned decompression limits
• monitoring oxygen partial pressure in a rebreather

Task loading is often identified as a key component in diving accidents, although statistically it is difficult to monitor because divers with more experience can cope with a more complex array of tasks and equipment. Simply controlling buoyancy while using a drysuit can call for great levels of attention in an inexperienced diver, but would be routine for an experienced cold water diver, and could be done safely while carrying a camera during a cave penetration or using a DPV.

See also

Cognitive load