Visual communication is communication through a visual aid and is described as the conveyance of ideas and information in forms that can be read or looked upon. Visual communication  relies on vision,The expression of ideas and information using visual forms or aids.  Visual communication involves the use of visual elements, such as drawings, illustrations and electronic images, to convey ideas and information to an audience. It has a greater power to inform, educate, or persuade a person or audience.   Visual communication is everywhere today, from electronic media like Web pages and television screens to environmental contexts such as road signs and retail displays.   Body language including gestures are part of such communication. Visual communications is a multidisciplinary field that combines traditional art with contemporary software applications to create images intended to convey a message.

Human communication has existed for about 30,000 years. In the beginning of recorded history, the vast majority  communication was not text based. Textual communication has been with us  for only 3,700 years. With the invention of tools like Gutenberg's movable type printing press in 1450,leads to  text as center stage and that period graphics were too costly to include .    The culture itself moves from textual to visual literacy. 

1)Cognitively: Graphics expedite and increase our level of communication. They increase comprehension, recollection, and retention. Visual clues help us decode text and attract attention to information or direct attention increasing the likelihood that the audience will remember.

2) Emotionally: Pictures enhance or affect emotions and attitudes.  Graphics engage our imagination and heighten our creative thinking by stimulating other areas of our brain which in turn leads to a more profound and accurate understanding of the presented material. The emotions influence decision-making: "(Emotions) play an essential role in decision making, perception, learning, and more ... they influence the very mechanisms of rational thinking."

Visual aids media

·         Chalkboard or whiteboard: Chalkboards and whiteboards are very useful visual aids, particularly when more advanced types of media are unavailable. They are cheap and also allow for much flexibility.

·          Poster board: A poster is a very simple and easy visual aid. Posters can display charts, graphs, pictures, or illustrations. The biggest drawback of using a poster as a visual aid is that often a poster can appear unprofessional. Since a poster board paper is relatively flimsy, often the paper will bend or fall over. The best way to present a poster is to hang it up or tape it to a wall.

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·         Handouts:Handouts can also display charts, graphs, pictures, or illustrations. An important aspect of the use of a handout is that a person can keep a handout with them long after the presentation is over. This can help the person better remember what was discussed. Passing out handouts, however, can be extremely distracting

·         Video : A video can be a great visual aid and attention grabber, however, a video is not a replacement for an actual speech. interesting

·         Projection equipment: There are several types of projectors. These include slide projectors, PowerPoint presentations, overhead projectors, and computer projectors.

Computer-assisted presentations:PowerPoint presentations can be an extremely useful visual aid, especially for longer presentations. For five to ten minute presentations, it is probably not worth the time or effort to put together a PowerPoint. 

source http://www.hawaii.edu/mauispeech/html/visual_aids.html