The longer the lecture the more were the nodding-off events per lecture

It is end-September, and the season for conferences and seminars has started in India. Generally, they invite experts from diverse disciplines in a conference, usually on a broad theme, while in a seminar, it is experts in a given discipline or even sub- disciplines, who exchange and critique ideas for collaborations, and thus, hopefully, advance the field. A typical attendee in conferences gets to hear lectures from a field that may not be familiar to him/her and thus has a learning opportunity. In a theme-special seminar, the attendee is a part-player in the game, has a broad familiarity with the theme and gets to listen to various nuances, some of which he learns, appreciates and gains from. Thus, conferences and seminars are useful.

Jump in nodders

However, there is one downside to this and that is this business of some or many in the audience nodding off their heads and taking naps while the presentation on the stage is on. Why do they do it, how often does this happen, what the “risk factors” for are such nodding off have been summarised in a 15-year-old publication by K. Rockwood et al., in the Canadian Medical Association Journal, Dec 7, 2004 issue (DOI:10.1503/emaj.1041570). In this humorous and satirical paper, they talk about how they conducted a surreptitious, prospective cohort study to examine how often physicians nod off during scientific meetings and to examine the risk factors for such nodding off. In a two-day lecture series, attended by 120 people, they found that the number of nodding off events per lecture (NOELs) per 100 attendees jumped to about 10 for a 15-20 minute lecture to over 22 or so when the lecture goes on for 30-40 minutes or more; the longer the lecture the greater the NOELs. They further ensured that “nodding off” is different from “nodding in agreement (NIA)” by the attendee who appreciated the point made by the speaker (nodding here was different in amplitude, the timing and the frequency).

Why did this happen? What are the risk factors? Several factors came to light. These were environmental factors (such as dim lighting, room temperature, comfortable seating), audiovisual (poor slides, not speaking into the microphone), circadian (early morning hours, postprandial or after a good breakfast or lunch) and “speaker-related” (speaking in a monotonous tone, boring direction). [Today, cell phones and mini-laptops are carried by most, if not all members in the audience. While the organisers announced ahead of the lectures that cell phones be switched off, or put on silent mode, the numbers of NOEL has probably come down as the attendee loses interest in the speech and moves to his/her phone or the computer on hand . If however the announcer insists that these be put off during the sessions, the NOELs will increase!].

The authors then accosted the NOEL people in the audience and politely asked them why they nodded off. First of all, when a nodder was told he was not alone, but many others did same too, most of them were reassured to know that it was not their individual fault! When asked whether he/she is likely to attend such a lecture again, some of them said yes, they always needed a nap; some others said yes they will if they are paid , and some would rather have their “teeth grilled” than attend! And finally, when asked whose fault led to nodding off, most said that it was entirely the speaker’s fault, and only a few said the fault was theirs!

Sustaining interest

What are the take-home lessons for speakers? How does he/she capture sustained interest in the audience? They cannot avoid dimly lit room, since the speaker uses slides, presentations and short videos. But a useful tip comes from a recent report in the literature. It says that the ideal lecture should have 37% text, 29% diagrams/figures and 33% videos. It would worth putting this fractionation into practice and see how it works. And in text slides (or presentations), it is best to stick to the “aspect ratio” (five units width and three units height of the image or text), large fonts so that reading the text is easy, and colour contrast between the background and text ( black or light blue background and a contract colour text). In addition, speak slow and clear and into the microphone (see the paper by Lim et al., from Singapore, titled “Sustaining interest during lectures with the use of multimedia”, Med.edu.online 2006, available from http://www.med-ed-online.org.

Finally, the brain-biology behind this has become better understood, as a recent publication from a team of Japanese and Chinese scientists has shown. They point out that the part known as the nucleus accumbens in the brain has a strong ability to induce a nap by activating a set of molecules called the A2A receptors. The main triggering molecule here is adenosine which activates the A2A receptor and induces sleep (Y. Oishi et al., Nature Communication 2017:8(1) DOI: 10.1038/S41467-017-00781-4). Besides adenosine there are other somnogenic molecules, which act on the A2A receptor as well. Popular sleep-inducing drugs potentiate the A2A receptor and put you to sleep. On the contrary, caffeine in coffee and tea block the receptor and keep you awake.

So next time you attend a lecture drink a cup of coffee before and keep awake, And when you give a lecture, follow the instructions of Lim and others from Singapore.

dbala@lvpei.org