What is Stimulus? As in perception, we become aware of our environment by selecting, organizing and interpreting the stimuli around us. Out of all the stimuli constantly bombarding our senses, we can perceive only a very few. We select and pay attention only to these few and ignore the rest. What we select and pay attention to, is something dictated by the nature of the stimuli reaching us and by our built-in tendencies. Many variables can influence our selection of stimuli from the environment. They can be stimulus as well as personal factors. Stimulus factors are those characteristics of stimuli that make them more compelling or attention-grabbing than others.


The Characteristics Of stimulus can be as follows.


It means the extent to which a stimulus is, in some physical way’ different important from stimulus the factor surrounding in perceptual stimuli. selection. Contrast is the most means common how much a stimulus is physically different from other stimuli around it. Different varieties of contrast can be seen, contrast Is closely related to change in stimulation and it is equally compelling. Any sharp difference can create a constant effect, an individual is attracted by it. Contrast in size tends to leap to awareness. But size itself, aside from any contrast is also a factor in perception. There are many ways in which stimuli differ e.g. brightness, size, motion, colour, pitch and loudness. Greater the contrast between any one of stimulus and the others around it; the greater the likelihood that stimulus will capture our attention.


If a radio is playing softly in the background while we are working,  we are likely to ignore it, but if the sound stops we will notice at once. Likewise, change in light is also perceived.


Certainly, our sense organs and nervous system are highly efficient in making us instantly aware of movement or any other change in the environment. Moving object catches the attention more easily than a static one. Motion is a physical dimension that determines the perceptual selectivity. It is a powerful factor in determining visual attention. Movement is also related to contrast because the contrast created by movement is important.


Typically the bigger the stimulus, the more likely we are to attend to it. To make attractive, huge billboards are erected. Here it is a size which determines our attention. That is why important terms are written in boldface type in different books, so we can notice them easily and attend to them as important. Generally, humans are more likely to be aware of a large object than of a small one. When we look at the front page of a newspaper, we notice the biggest headline first.


Intensity has also great effect. The brighter or louder the stimulus, the more likely we are to pay attention to it.


Context, in which a stimulus occurs, makes a difference. While facing bright lights, a dim light can be more attractive.


There is another stimulus characteristic that can determine attention, which is repetition. The more often a stimulus is presented, the more likely it will be attended to everything else being equal. If stimuli are constantly available to us we may adapt to them and no longer notice them. So many examples convince us about the value of repetition. Instructors also repeat the important points while delivering a lecture. The people who schedule T.V. commercials, want us to attend to their messages, they rely on the technique of repetition.