The Compleat Lecturer- III: Lecture theatre size and design
Oxford Magazine. 2017; No. 389 (Fifth Week, Michaelmas Term): 11-12
A perennial question is the ratio of teacher and students in a class: one teacher to how many students? How large a lecture class can effectively, or optimally, be taught at once?
I would argue that for specifically educational purposes (as contrasted with entertainment, or mental stimulation) there is something like an absolute maximum size for teaching lectures; which size depends upon how good a lecturer, how well-designed the lecture theatre, and how motivated and disciplined are the students.
For average situations, this maximum is about two hundred – and numbers in excess of this (e.g. those sitting far away) will probably be getting very little from the lecture while – by their disengagement, and inattention – be damaging the experience of the rest. With too-large lectures, only some smaller proportion of the class will truly be engaged and actively-learning: this situation constitutes a type of fake teaching, because it pretends to something it cannot deliver.
At one time I mostly lectured in a steeply-raked, two-tier Victorian-built theatre that sat about 250, and yet the lectures ‘worked’, because none of the audience were very far away from the lecturer (the balcony seating jutted forward over the lower seats), so despite the numbers there were good acoustics and sight-lines. Furthermore, the large classes were usually of cohesive, highly intelligent and motivated groups (e.g. medical or dental students) - keen and able to learn.
But that was an ideal situation; not readily transferable to other circumstances such as sub-optimal lecture theatres, and mixed-subject classes including less-motivated, less competent students. As a broad generalisation, applicable to most lectures (by most lecturers to most classes) the ratio ought to be no more than about one-to-a-hundred; that is the lecture theatre should not usually be larger than a hundred seats (assuming that the genuine intent is that all students present may be engaged in active classroom learning).
A hundred students in a class is actually a very large number; and keeping classes down to this size (and only as big as this, in a reasonably well-designed venue) would not be regarded as an onerous constraint by any serious educational institution… however (by what they actually do, rather than what they say) sadly few institutions really are serious about education.
So there is often pressure to push above even this maximum class size; for example by using audio-visual amplification technology to address many hundreds of students in vast, or multiple-simultaneous, venues… These, I can only regard as pseudo-lectures; and they have little to do with a serious attempt to provide real education.
At most, such situations may attain the level of those ‘dictation-transcription’ lecture of the Medieval universities; in which both lecturer and audience have ‘engaged autopilot’. But in an era of abundant, accessible and good quality textbooks, such exercises are largely redundant; and insofar as far too many modern lectures conform to this description, then this probably accounts for the generally poor reputation of the lecture method.
In fact, if modern students have only attended ‘PowerPoint’-style presentations to audiences numbered in their hundreds; in which the proceedings occur in the dark, making note-taking impossible; surrounded by people on laptops and mobile phones, browsing the internet and social messaging; the invisible teacher merely an amplified, disembodied and un-localised voice reading-off the slides; and the entire substantive content available in lecture handouts or on the internet - then these students have, in fact, never actually experienced a real lecture.
Such unfortunate students are being palmed-off with a dishonest simulacrum of what lectures can and ought to be.
The size of audience that can effectively be lectured-to partly depends on the specific venue. Indeed, lecture theatre design is very important – and many (probably most) lecture theatres are significantly (sometimes grossly) unfit for purpose.
For small classes, the specifics of a lecture theatre are relatively less important – since everyone can see and hear what is happening; but as the size of the class increases, the design becomes more and more important; until with large classes (above about 100) only the very best-designed lecture theatres are adequate.
It is necessary that the audience in a lecture be in audio-visual contact with the lecturer. In general, the closer the physical proximity of lecturer and audience, the better. For big classes this means that the lecture theatre must have a steep rake; that is, steeply-sloped seats (as in a traditional theatre – some Medieval lecture theatres were positively vertiginous in this respect!); so that all students are close enough that they can clearly hear and see the lecturer and any visuals, because the sight-line is above the heads of the students sitting in front.
Another aspect of sight-lines is that all members of the audience need to be able to maintain ‘eye contact’ with the lecturer. This implies the lecture theatre should be well lit, with plenty of bright lights especially at the front where the lecturer and writing boards are located. In sum, the level of brightness in a lecture theatres should be more like a bright kitchen (500 Lux) than a gloomy bedroom (50 Lux). As well as encouraging eye contact, and maintaining alertness, bright lighting also enables lecture notes to be created more effectively.
Naturally, the benefits of a bright environment also mean that the ‘house lights’ (illuminating the audience) should be kept-on for most of the lecture – with the whole room lit such that everybody can see everybody else. The practice of showing slides on a screen in a dark room should be kept to a minimum (when it is not possible to eliminate slides altogether).
As well as sight-lines, the lecture theatre acoustics must be good; including an absence of background noises and external noises (e.g. from traffic, builders, or conversations from students passing outside). Sound-proofing is necessary both to avoid distraction, and in order that all students present can easily hear what is being said without artificial means of amplification.
The use of microphones may sometimes be unavoidable for some lecturers and some venues (even I have occasionally been forced into this by laryngitis – although I have trained myself to ‘project’ the voice like a stage actor). But microphones should be discouraged and the usage of amplification regarded as exceptional - since electronic reproduction interposes a psychological barrier between lecturer and audience. (For example, most amplification systems do not localise the voice to the exact place from which the lecturer is speaking – which creates an alienating dislocation.)
Of the other ‘sensory’ factors, the most important – and most neglected - is ventilation. Lecture theatres simply must have an ample flow of cool air – because a warm, stuffy, humid lecture theatre may become soporific such as to render a lecture futile. Therefore it is better for the lecture theatre to be a bit too cold than too hot; and too draughty than too stuffy. After all, in extremis the lecturer and students can always wear an extra layer!
Furthermore, and vitally; taking lectures seriously means building enough lecture theatres of the necessary size, and designing them to be effective environments for learning. There is no need to ‘reinvent the wheel’ – colleges should simply find and copy the best examples of lecture theatre design (which are often the oldest). Any motivated lecturer or serious student will be able to say which are the best lecture theatres - unmotivated lecturers and non-attending or unserious students should have no say in the matter!