Applied cognitive psychology
Central concern of applied cognitive psychology: discover ways to ↘ the tendency we all have to make errors in various
Activation-trigger-schema theory: There can be several schemas for different kinds of action, and more than one schema
can be activated at the same time. schemas may be inappropriately activated, resulting in attentional errors.
Oops I did it again effect: A habitual sequence of action continues to operate without much attention, and a newer,
intended action sequence never gets activated.
Participants are very poor at remembering to do a postponed task.
Understand errors by classifying them in terms of possible sources of error:
1. Errors due to faulty formulation of intentions
Mode errors: carrying out an action that would be appropriate for one situation, but not for the situation in
which we happen to find ourselves.
E.g. trying to take off eyeglasses when not actually wearing them, pick up the phone and say “come in”
Description errors: Errors that occur because we do not have a detailed enough understanding of the situation
E.g. a person intends to pour orange juice in a glass, but pour it in a coffee cup next to it.
2. Errors due to faulty activation of a schema
Capture errors: Errors that occur when a familiar schema captures behaviour in the place of an unfamiliar one.
E.g. When we are trying to do something instead of an overlearned sequence: Stroop task.
E.g. errors due to loss of activation of the appropriate schema: walking into a room and then not sure
why you’re there.
3. the right schema has been activated, but it is triggered inappropriately
Anticipation errors: a response may occur earlier in a sequence than it should if it is only being elicited by the
immediately preceding stimulus.
E.g. typing errors (wrapid writing instead of rapid writing)
E.g. Spoonerism (you have tasted two worms instead of you have wasted two terms)
Existence of errors points out the importance of monitoring our behaviour.
Similar errors occur in professional settings, but their consequences are much more serious= continuous monitoring of
activity is necessary to avoid error. Errors find fertile ground where there is confidence.
Ergonomics: The study of people in relation to their working environments.
Ergonomist help design objects and machines so that we can interact with them efficiently and with the maximum
amount of satisfaction.
Objects should be made user-friendly: help a person to perform a task in a natural way, which is easy to understand and
use. Changing an object to solve a problem may actually create another one.
User-friendly: flexible straw.
User-unfriendly: child-proof medicine bottle.
Asymmetry between understanding and prediction: One can understand something extremely well and yet not be able
to predict its future occurrence. Conversely, one can predict something reasonably well, without having a very good
understanding of why those predictions work. The user interface
Work situations can be analyzed in terms of three different interfaces:
1. Organizational interface: relation between organization and the types of tasks it requires.
2. Task interface: relation between a job and the devices required to perform the job
3. User interface: relation between the person and the machine being used to perform a task. Crucial.
Cognitive ergonomics: The combination of cognitive psychology and ergonomics used to understand the
Desirable for the user interface to be designed to make use of the user’s existing knowledge, in order to minimize the
amount of learning required to interact with the computer.
Subject of research over the past decades.
Alphabetical arrangement of letters did not last long: too easy to use.
QWERTY keyboards followed.
Typing speed on an alphabetic keyboard is not as fast as on a QWERTY keyboard. Most people have at least some
experience with the QWERTY keyboard.
Attempts to reintroduce the alphabetical keyboard failed. Example of the way that accidental series of events may lock
technology into a particular irreversible path.
Different contexts allow for different solutions (e.g. numeric keypad on computers vs. phones)
Text messages fill a gap: combine immediacy of a phone and convenience of an answering machine and premeditation
Textish: text messages are written in a special code because the keypad on a mobile phone is very small.
Tendency to use textish ↗ with the intimacy of the relationship between sender & receiver.
Textish resembles inner speech. The less the social distance between oneself and another, the more communication will
approximate speech for oneself.
text messages illustrate the fact that if a device can satisfy a need, then people will use it no matter how labour-
intensive it is.
Fitt’s law: Specifies the difficulty of moving a stylus to a target. This difficulty will vary as the distance to the target
varies. The farther the stylus has to be moved, the more difficult the task. It will also vary as the size of the target varies.
The narrower the target, the more