According to Alf Rehn, “the
average attention span among people who listen to speeches is estimated to be
somewhere in the 5–10 minute span, and often towards the lower end of this.” (alfrehn.com)
However, he also claims that with a great speech you can hold people’s
attention for at least 20 minutes.
Rob Norris has summarized what
we have all noticed about presentations with slides: “Audiences read much
faster than you talk (250 words-per-minute vs. about 125), which is why they’ll
almost always opt to read and be done with the slide before you’ve reached even
the third bullet point.” (Quoted from Anderson, 2017.) Remember: do not read
the text directly from your slides!
Before you decide on any visual
aids, you should ask yourself if your presentation really needs them. All
audiences prefer you to talk to them rather than to just show some printed
text! Besides, visuals as such do not necessarily improve your speech. They
have to be carefully selected to achieve the goal you want. Beware of “Death by
PowerPoint”!