In addition, the neurons have a very low threshold of activation - they respond quickly even to weak stimuli.

One leading method is based on signal detection theory, developed for cases of very weak stimuli.

A weak stimulus, then, may be enough to set off some of the fibers and not the others.

The weaker stimulus will be replaced by the stronger stimulus.

The first is the equivalent phase, in which the brain gives the same response to both strong and weak stimuli.

The second is the paradoxical phase, in which the brain responds more actively to weak stimuli than to strong.

An effect of these factors is that people are particularly sensitive to perceive certain things, detecting them from weaker stimuli than otherwise.

For mechanical signals, noise serves to boost weak stimuli.

In this way a weak stimulus may come to have an acquired cue value (Rivers 1964).

The joint subsystems hypothesis is most applicable in real-world contexts that contain mixed stimuli: strong, weak, punishment, and reward.