Perceptual Salience vs. Thematic Relevance

Complexity of the subject matter may not be the only reason for difficulties that learners sometimes have with animations. It seems that problems can also arise from the perceptual effects of such presentations. In a poorly designed animation, the information that learners notice most readily in the animation may not be the information that is of greatest importance. Conversely, information that is relatively inconspicuous may be very important. You can see an example of this in the top right hand corner of the accompanying animation. Tucked away here is a small grey-colored valve whose subtle movement lets air into this pumping system (which is where the bubbles come from). However, it's nowhere near as noticeable as the big, more central, orange-colored valve that is going up and down so obviously. The point is that animations should not appear in a vacuum and most will require accompanying explanation.

Obviously, perceptibility of information does not necessarily correspond with its actual relevance to the learning task to be performed. Features of the animated display that are most conspicuous because of their contrast with the rest of the display are not always the best place for learners to direct their attention. In other words, there can be a poor correspondence between the perceptual salience ('notice ability') of a feature and its thematic relevance, and an accompanying text is needed to correct this.

This correspondence problem can occur with both static and animated graphics. On a purely perceptual level, our attention tends to be attracted by some parts of a static display more than by other parts due to their visuospatial properties. For example, an object that is centrally placed, relatively large, unusually shaped, and of a sharply contrasting color or texture is likely to 'jump out' of the display so that we notice it very easily. Other items in the display may receive correspondingly less attention as a result. Well-designed static educational graphics take advantage of these perceptual effects. They manipulate the characteristics of the display in order to direct learner attention to the most relevant information. This helps to ensure that the learner will extract the required information from the display. There is a problem in the design of the animation shown above in this respect. Unfortunately, there are many 'educational' graphics being produced that fail to provide learners with sufficient support of this type. Designers of animation need to take such consideration into account.

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