There’s a thing called the Ebbinghaus forgetting curve which says that
within an hour you’ve forgotten half of what you’ve been told,
within a day two thirds has gone,
and within a month 80% has gone and there’s only 20% left.
The ramifications for presentations are therefore:
1 – Decide on one clear message and hammer away at that. If they just remember one thing, what do you want it to be? Design your whole talk around that message.
2 – If you can have a refresher straight afterwards and then again a week later then the retention is much better, and with two or three refreshers it nearly all goes into the long term memory. These could be done by talk part 2, a follow-up email, or in the case of training, by the line manager getting involved and having a meeting with the person straight away to ask “What did you learn? What will you do differently?” and then a few weeks later “How have you been getting on with you list of planned changes?” Line managers are really important in getting training to work and to be good value for money!
You can see here http://www.cleptestreview.com/supporting-images/projected-forgetting-curve-small.png that even just three refreshers bring the long term retention up from 20% to 80% – a huge improvement!
3 – taking notes is a way of immediately doubling the number of times your brain sees the message, and then if you go through the notes afterwards and condense them, that’s your first refresher
4 – Another way to get a repeat in a fun way is to get whoever has been on a course to tell their colleagues all about it. And of course this means that the others get a (sort of) course for free; and the person on the course has to pay extra attention because they know that later they will have to regurgitate it.
The above apply to people giving talks or training sessions, people who are paying for training sessions / sending their people on training sessions or to talks, and to those who attend talks and training and want to gain as much from it.
Finally, if you’re delivering a talk and you want it to be remembered, there’s the excellent old chestnut which says that activities are much better than just being talked at – “If I am told it I forget, if I see it I remember, if I do it I understand”…
Onwards and upwards