Attention and perception shortcomings can clearly impinge on decision making. Perceiving something incorrectly may mean that an incorrect decision is made, resulting in an inappropriate action. The earlier image (Functional Model of human information processing) also shows the dependence on memory to make decisions. It was explained earlier that sensory and short-term memory have limited capacity, both in terms of capacity and duration. It is also important to bear in mind that human memory is fallible, so that information:
- May not be stored;
- May be stored incorrectly;
- May be difficult to retrieve.
All these may be referred to as forgetting, which occurs when information is unavailable (not stored in the first place) or inaccessible (cannot be retrieved). Information in short-term memory is particularly susceptible to interference, an example of which would be trying to remember a part number whilst trying to recall a telephone number.
It is generally better to use checklists and aides-memoires rather than to rely upon memory, even in circumstances where the information to be remembered or recalled is relatively simple. For instance, a pilot may think that he will remember a frequency setting without writing it down, but between speaking to ATC and dialling in the frequency, he may forget the setting or confuse it (possibly with a different frequency setting appropriate to another Sector with which he is more familiar). Additionally, if unsure of the accuracy of memorised information, a pilot should seek to check it, even if this means consulting the manual or chart to do so. Noting something down can avoid the risk of forgetting or confusing information.