“So also with the effect of set on perception (perceptual set is another aspect of the phase sequence, closely related to attention). It has been shown that in certain circumstances one sees what one expects, or is set, to see. But this is no general rule, else one would be incapable of seeing the unexpected. When a stimulation is sufficiently strong or distinctive from its background, and familiar or composed of familiar parts, it will be capable of initiating its own phase sequence, regardless of what other phase sequence may be going on at the moment. (If the new phase sequence is incompatible with the pre-existing one, startle or emotion may result.) The sensory event is capable of taking control of central action, just as in other circumstances the central action is capable of reinforcing one sensory event at the expense of a second.”