These occur when a device has modes of operation in which the same action sequence has different meanings. If the mode is not visible, the user can forget the mode and use the sequence appropriate for the wrong mode. Even if the mode is visible, the user may not attend to whatever is signaling the current mode. All seven stages of action can be and are simultaneously specified at various levels of detail. Even when a person detects a slip, if she cannot identify the level of detail at which it occurred, she will find it difficult to correct the error.
Human memory works by forming links or associations, between and among schemas.
Much thought consists of extrapolating from one schema to another. Each neuron has connections to thousands of neighbor neurons. Each neuron sends signals to its neighbors. Activation signals add to the input of the neighbor. Inhibition signals subtract from the input of the neighbor.