13.2 Functions of Presentation Aids

Why should you use presentation aids? If you have prepared and rehearsed your speech adequately, shouldn’t a good speech with a good delivery be enough to stand on its own? While it is true that impressive presentation aids will not rescue a poor speech, a good speech can often be made even better by the strategic use of presentation aids. Presentation aids can fulfill several functions: they can serve to improve your audience’s understanding of the information you are conveying, enhance audience memory and retention of the message, add variety and interest to your speech, and enhance your credibility as a speaker. Let’s examine each of these functions.

Improving Audience Understanding

Human communication is a complex process that often leads to misunderstandings. If you are like most people, you can easily remember incidents when you misunderstood a message or when someone else misunderstood what you said to them. Misunderstandings happen in public speaking just as they do in everyday conversations.

One reason for misunderstandings is the fact that perception and interpretation are highly complex individual processes. Most of us have seen the image in which, depending on your perception, you see either the outline of a vase or the facial profiles of two people facing each other. Or perhaps you have seen the image of the woman who may or may not be young, depending on your frame of reference at the time. This shows how interpretations can differ, and it means that your presentations must be based on careful thought and preparation to maximize the likelihood that your listeners will understand your presentations as you intend them to do so. (You can see these images at http://members.optusnet.com.au/~charles57/Creative/Drawing/vases.htm and https://www.youtube.com/watch?v=P9iv173VtGM.)

As a speaker, one of your basic goals is to help your audience understand your message. To reduce misunderstanding, presentation aids can be used to clarify or to emphasize.

Image illustrating coriolis effect

Figure 13.1 – Coriolis Effect


Clarification is important in a speech because if some of the information you convey is unclear, your listeners will come away puzzled or possibly even misled. Presentation aids can help clarify a message if the information is complex or if the point being made is a visual one.

If your speech is about the impact of the Coriolis Effect on tropical storms, for instance, you will have great difficulty clarifying it without a diagram because the process is a complex one. The diagram in Figure 13.1 (“Coriolis Effect”) would be effective because it shows the audience the interaction between equatorial wind patterns and wind patterns moving in other directions. The diagram allows the audience to process the information in two ways: through your verbal explanation and through the visual elements of the diagram. By the way, the Coriolis Effect is defined as “an effect whereby a mass moving in a rotating system experiences a force (the Coriolis force ) acting perpendicular to the direction of motion and to the axis of rotation. On the earth, the effect tends to deflect moving objects to the right in the northern hemisphere and to the left in the southern and is important in the formation of cyclonic weather systems.” You can see why a picture really helps with this definition.

Figure 13.2 (“Model of Communication”) is another example of a diagram that maps out the process of human communication. In this image you clearly have a speaker and an audience with the labels of source, channel, message, receivers, and feedback to illustrate a basic model of human communication. As with most models, it is simplified. (Can you remember what two components of the communication process, explained in Chapter 1, that are missing here?)

Figure 13.2 – Model of Communication


Image of petroglyph

Figure 13.3 – Petroglyph example


Graphic illustration of ten drops of usable water per one cup of polluted water

Figure 13.4 – Planetary Water Supply


Another aspect of clarifying occurs when a speaker wants to help audience members understand a visual concept. For example, if a speaker is talking about the importance of petroglyphs in Native American culture, just describing the petroglyphs won’t completely help your audience to visualize what they look like. Instead, showing an example of a petroglyph, as in Figure 13.3 (“Petroglyph”) can more easily help your audience form a clear mental image of your intended meaning.

Chinese Lettering

Figure 13.5 – Chinese Lettering Amplified. Source: Image courtesy of Wikimedia,


When you use a presentational aid for emphasis, you impress your listeners with the importance of an idea. In a speech on water conservation, you might try to show the environmental proportions of the resource. When you use a conceptual drawing like the one in Figure 13.4 (“Planetary Water Supply”), you show that if the world water supply were equal to ten gallons, only ten drops would be available and drinkable for human or household consumption. This drawing is effective because it emphasizes the scarcity of useful water and thus draws attention to this important information in your speech.

Another way of emphasizing that can be done visually is to zoom in on a specific aspect of interest within your speech. In Figure 13.5 (“Chinese Lettering Amplified”), we see a visual aid used in a speech on the importance of various parts of Chinese characters. On the left side of the visual aid, we see how the characters all fit together, with an emphasized version of a single character on the right.

So, clarifying and emphasizing are two roles that support the “Improving Audience Understanding” purpose of presentation aids. What are other purposes?

Aiding Retention and Recall

The second function that presentation aids can serve is to increase the audience’s chances of remembering your speech. An article by the U.S. Department of Labor (1996) summarized research on how people learn and remember. The authors found that “83% of human learning occurs visually, and the remaining 17% through the other senses—11% through hearing, 3.5% through smell, 1% through taste, and 1.5% through touch.”

For this reason, exposure to an image can serve as a memory aid to your listeners. When your graphic images deliver information effectively and when your listeners understand them clearly, audience members are likely to remember your message long after your speech is over. Moreover, people often are able to remember information that is presented in sequential steps more easily than if that information is presented in an unorganized pattern. When you use a presentation aid to display the organization of your speech (such as can be done with PowerPoint slides), you will help your listeners to observe, follow, and remember the sequence of information you conveyed to them. This is why some instructors display a lecture outline for their students to follow during class and why a slide with a preview of your main points can be helpful as you move into the body of your speech.

An added plus of using presentation aids is that they can boost your memory while you are speaking. Using your presentation aids while you rehearse your speech will familiarize you with the association between a given place in your speech and the presentation aid that accompanies that material.

Adding Variety and Interest

A third function of presentation aids is simply to make your speech more interesting. For example, wouldn’t a speech on varieties of roses have greater impact if you accompanied your remarks with a picture of each rose? You can imagine that your audience would be even more enthralled if you had the ability to display an actual flower of each variety in a bud vase. Similarly, if you were speaking to a group of gourmet cooks about Indian spices, you might want to provide tiny samples of spices that they could smell and taste during your speech.

Enhancing a Speaker’s Credibility

Presentation aids alone will not be enough to create a professional image. As we mentioned earlier, impressive presentation aids will not rescue a poor speech. Even if you give a good speech, you run the risk of appearing unprofessional if your presentation aids are poorly executed. Conversely, a high quality presentation will contribute to your professional image. This means that in addition to containing important information, your presentation aids must be clear, clean, uncluttered, organized, and large enough for the audience to see and interpret correctly. Misspellings and poorly designed presentation aids can damage your credibility as a speaker.

In addition, make sure that you give proper credit to the source of any presentation aids that you take from other sources. Using a statistical chart or a map without proper credit will detract from your credibility, just as using a quotation in your speech without credit would. This situation will usually take place with digital aids such as PowerPoint slides. The source of a chart or the data shown in a chart form should be cited at the bottom the slide.

If you focus your efforts on producing presentation aids that contribute effectively to your meaning, that look professional, and that are handled well, your audience will most likely appreciate your efforts and pay close attention to your message. That attention will help them learn or understand your topic in a new way and will thus help the audience see you as a knowledgeable, competent, and credible speaker. With the prevalence of digital communication, the audience expectation of quality visual aids has increased.

Avoiding Problems with Presentation Aids

Using presentation aids can come with some risks. However, with a little forethought and adequate practice, you can choose presentation aids that enhance your message and boost your professional appearance in front of an audience. One principle to keep in mind is to use only as many presentation aids as necessary to present your message or to fulfill your classroom assignment. The number and the technical sophistication of your presentation aids should never overshadow your speech.

Another important consideration is technology. Keep your presentation aids within the limits of the working technology available to you. Whether or not your classroom technology works on the day of your speech, you will still have to present. What will you do if the computer file containing your slides is corrupted? What will you do if the easel is broken? What if you had counted on stacking your visuals on a table that disappears right when you need it? Or the Internet connection is down for a YouTube video you plan to show?

You must be prepared to adapt to an uncomfortable and scary situation. This is why we urge students to go to the classroom well ahead of time to test the equipment and ascertain the condition of items they’re planning to use. As the speaker, you are responsible for arranging the things you need to make your presentation aids work as intended. Carry a roll of masking tape so you can display your poster even if the easel is gone. Test the computer setup. Have your slides on a flash drive AND send it to yourself as an attachment or upload to a Cloud service. Have an alternative plan prepared in case there is some glitch that prevents your computer-based presentation aids from being usable. And of course, you must know how to use the technology.

More important than the method of delivery is the audience’s ability to see and understand the presentation aid. It must deliver clear information, and it must not distract from the message. Avoid overly elaborate presentation aids. Instead, simplify as much as possible, emphasizing the information you want your audience to understand.

Another thing to remember is that presentation aids do not “speak for themselves.” When you display a visual aid, you should explain what it shows, pointing out and naming the most important features. If you use an audio aid such as a musical excerpt, you need to tell your audience what to listen for. Similarly, if you use a video clip, it is up to you as the speaker to point out the characteristics in the video that support the point you are making—but probably beforehand, so you are not speaking over the video. At the same time, a visual aid should be quickly accessible to the audience. This is where simplicity comes in. Just as in organization of a speech you would not want to use 20 main points, but more like 3-5, you should limit categories of information on a visual aid.

Sketch of acupuncture chart from Ming Dynasty

Figure 13.6 – Acupuncture Charts. Source: Image on the left from Wikimedia, http://
commons.wikimedia.org/wiki/File:Acupuncture_chart_300px.jpg. Image on the
right © Thinkstock


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