Saturday, 21 July 2007

Lectures - a highly effective teaching method


Lectures are such an effective teaching method because they exploit evolved human psychology to improve learning

Bruce G. Charlton

Medical Hypotheses. 2006; 67: 1261-1265.


Lectures are probably the best teaching method for many students in many circumstances; especially for communicating conceptual knowledge, and where there is a significant knowledge gap between lecturer and audience. However, the lack of a convincing rationale has been a factor in under-estimating the importance of lectures, and there are many who advocate their replacement with written communications or electronic media. I suggest that lectures are so effective because they exploit the spontaneous human aptitude for learning from spoken (rather than written) information. Literacy is a recent cultural artefact, and for most of their evolutionary history humans communicated by direct speech. By contrast with speech, all communication technologies – whether reading a book or a computer monitor – are artificial and unnatural. Furthermore, learning is easier during formal, quiet, real-time social events. The structure of a lecture artificially manipulates human psychology to increase vigilance, focus attention, and generate authority for the lecturer – all of which make communications more memorable for the student. Instead of trying to phase-out lectures, we should strive to make them better by understanding that lectures are essentially formal, spoken, social events.


Despite the lecture method being so unpopular among professional educational advisers, reformers and intellectuals generally – and almost annual declarations that information technology is just about to render lectures obsolete – many scientists continue to give lectures and students continue voluntarily to attend them. The fact that lectures have survived so much official opprobrium suggests that they are a much more effective teaching method than they are given credit for.

Indeed, existing practice suggests that properly structured lecture series may be the best teaching method for many subjects and many students, and lectures may be especially well-suited to the transmission of conceptual and systematic knowledge [1]. Lectures are therefore usually the standard medium for teaching science up to the point where the student begins to specialize and train as a practicing scientist, at which point a more individualized and skill-orientated training becomes necessary.

In itself, the greater ease of learning from lectures may indeed account for some of the disdain with which many intellectuals regard lectures, since intellectuals are experts at the cognitively-challenging business of learning by solitary reading. For example, intellectuals may deride clear, comprehensible and enjoyable lectures as ‘spoon-feeding’ students; with the implication that students should be forced to work hard to find their basic knowledge in the same way that intellectuals do for their advanced knowledge. This was perhaps appropriate when science teaching was mainly for training future professional scientists; but now that science is taught mainly as a ‘general education’, the acquisition of knowledge is more important than the process by which it is attained [2].

Lectures are also criticized as inculcating a ‘passive’ attitude to learning; and any passive tendency is encouraged by the mistaken practice of giving students handouts or written summaries of the lecture contents, so that students are implicitly expected just to sit and listen, and neither organize nor write-down the information supplied by the lecturer. But we need to be clearer that making learning easier is an admirable educational objective, assuming that what is being learned is worthwhile (as it is in the sciences). Making learning easier is especially important for the less-naturally gifted proportion of the population who make up an increasingly large number of higher education students in advanced societies due to the massive recent and continuing expansion of colleges and universities [3]. If knowledge is valuable, then we should embrace effective methods of inculcating knowledge: the easier the better.

I suggest that there are many advantages to lectures which seem obvious yet are seldom noted or acted-upon. The first is that it is easier for most people to learn conceptual information from spoken communications than from reading – and the essentially aural nature of information has important implications for lecture organization. The second is that the real-time, human-presence of a lecturer and the social context of a formal lecture makes it easier for most students to remain alert, focus attention and remember what is said than when students are required to work alone. A third factor which deserves recognition is that the proper unit of educationally valuable lectures is a course of lectures (i.e. repeated interactions between the same teacher and the same class), not an one-off talk.

I conclude that lectures are ‘spontaneously’ easier to learn-from than are written or electronic media, and the reason is probably that they exploit evolved human psychology. In this sense it is ‘human nature’ to learn by hearing information in social situations, because this was the medium and context in which ancestral hunter-gatherers did most of their learning.

The effectiveness of lectures

Lectures work, but nobody seems to know why. The lack of an accepted rationale for the method seems to make people feel guilty about using lectures. At best lectures are taken for granted (which makes it unlikely that they will be improved), at worst attempts are made to replace lectures with almost anything else.

We must first accept that it is completely impractical and unaffordable to replace lectures with individual or small-group teaching in modern mass higher education systems [3], and attempts to do so (in any more than a token or symbolic fashion) will probably merely lead to less teaching of students. More usually ‘distance learning’ methods are introduced, such as teaching by e-mail and internet; but this brings attendance-based universities into competition with cheaper, more convenient and (probably) better-quality distance learning institutions. In the mania to replace lectures, absurd gestures may be made such as abandoning real teaching altogether, and instead getting groups of students to ‘teach-each-other’. (Student-led education might arguably be valuable among the cleverest and best-educated students, but is a totally misguided strategy for mass higher education.)

Perhaps the most convincing evidence of lectures’ effectiveness comes from what people actually do, rather than what people say. I find it highly significant that lectures are especially used in teaching the most quantitative and systematic sciences, and for intensive professional training courses such as medicine, engineering and law. In other words, lectures are a focus of teaching in exactly the situations where transmission of knowledge is most vital, and in subjects where learning is most easily and validly measurable. Of course, lectures will only get you so far, and individual teaching by ‘apprenticeship’ supported by self-directed study remain necessary for learning specialized and high level skills.

It is striking that, despite increasing choice of alternatives, the great majority of students continue to enrol in attendance-based and residential universities where lectures are a primary mode of instruction. And, when at university, they usually show-up for lectures, even when the lectures are not compulsory. So, students still choose lecture-based teaching despite the ready availability of more convenient alternative qualifications from highly-reputable ‘distance learning’ institutions which have grown-up to exploit new communication technologies [4]; such as the UK Open University or the University of Phoenix in the USA. But although such distance-learning is often both high in quality and much cheaper, it has added to, rather than displaced, the demand for attendance-based, lecture-focused educational institutions. Apparently, many students experience difficulties in learning in solitude even from the finest written or audio–visual media.

Taking all these observations together, there seems to be ample prima facie evidence that lectures are probably the best practicable teaching method in many circumstances and for many students. However, it is not generally understood why lectures are useful, and because this rationale is not understood, the conduct of lectures has often been changed in ways that make them less effective – usually by undermining the focus upon spoken communication by inappropriate use of visual aids or excessive emphasis on written support material.

Lectures are essentially spoken – written handouts undermine lectures

The specific reason for their effectiveness is that lectures are essentially a form of spoken communication which is delivered to an audience by an actually present and visible person through a series of repeated social interactions. A lecture therefore constitutes a formally structured social event which fits evolved ‘human nature’ and artificially manipulates human psychology to improve learning.

It is easy for educated people in advanced societies to forget that literacy and solitude are both relatively-recent cultural artefacts. In the hunter-gatherer societies in which our (neuro-anatomically identical) ancestors dwelled for many tens of thousands of years, information was communicated mainly face-to-face and by direct speech, and individuals were almost never alone [5]. By contrast, all communication technologies – whether reading a book, audio–visual media, or a computer monitor – are artificial and contrived; and studying alone is a difficult skill with widely varying levels of attainment. This is probably the major reason why so many people find it easier to learn from a spoken lecture and in groups.

Attending a course of lectures requires a long-term commitment to be in the necessary place at the proper time. Because the main medium of communication in a lecture is the spoken word, what is spoken should be regarded as the essence. The only way to make lecture attendance unimportant is to diminish the effectiveness of the lecture. Only if lectures are sub-optimal can students miss them without incurring some disadvantage. If a student is not present and listening, he or she will not obtain the advantage of attending a lecture; and will have to make-do with solitary personal study. This is undeniably inconvenient, but it is intrinsic to the medium.

Therefore, when a lecture course is the focus of teaching, care should be taken not to sacrifice the essence of lectures by confusing students over the core learning activity which is expected of them. In lecture-based course, students should understand that one major expectation is that they should attend lectures or be prepared to take the consequences of disadvantaged learning. In order to make the most of their natural strengths, lectures need to maintain their proper focus on speaking as the primary form of communication.

But students may miss lectures through no fault of their own, as well as for less admirable reasons. So it is tempting to try and ameliorate the inevitable educational disadvantages to students who cannot (or prefer not to) attend lectures by providing identical or more-detailed material as handout – perhaps distributed by the internet. Once such handouts are established as an element of the teaching, it is tempting to distribute them, or make them available online, in advance of spoken lectures. But these temptations should be resisted, because handouts will – by their abstract objectivity – usurp the primacy of the spoken lecture.

It is hard to exaggerate the extent to which hand-outs can damage the effectiveness of lectures. A lecture is compelling substantially because it is here-and-now, a situation in which the student must concentrate, listen, understand – and these activities cannot be put-off until later. The intensity of a lecture depends on this necessity for the student to focus.

And in order to have a record of information for understanding and revision, the student must record the lecture in their own words, and they must do it now. But the existence of hand-outs or transcriptions usurps this fundamental responsibility of the student. A handout stands-between the student and the real-time lecture in the same way that a video-camera stands between a tourist and landscape in which they are standing. To see a lecture through the lens of a hand-out is as impoverished a perspective as seeing the Alps through the viewfinder of a camera.

As well as increasing immediate attentiveness, lecture notes also make the lecture into an active mode of learning because note-taking requires ‘deep-processing’ forms of learning, by imposing a requirement to understand, abbreviate and re-organize in-coming information. Deep-processed information is better remembered.

More generally, lecture teaching methods should not allow verbal information to become subordinated to ‘visual aids’. It is tempting to make lectures more entertaining by adding attention-grabbing graphics. But complex visual material is usually distracting rather than educational. TV, video, animations and the like are so attention-grabbing that they break the conceptual thread of spoken discourse. Switching back-and-forth between audio–visual technology and the spoken voice involves a repeated cognitive ‘gearchange’ that relatively disadvantages speech.

The primary visual aid should be the lecturer him- or her-self – the effective lecturer is an actor or orator. In particular, the audience should clearly see the lecturer’s face, and eye-contact with the lecturer is vital. A lecture which takes place in the dark while viewing slides, where a disembodied voice intones sentences, can hardly be described as a lecture at all since it lacks the basis of a social event. Attending a lecture in the dark is more like visiting the cinema than participating in a social event.

A lecture is a means to an end, which is learning. Methods to attract attention and entertain the audience should therefore be subordinated to the over-arching educational imperative.

Lectures as social events

As well as being spoken communications, lectures are properly delivered by an actually present individual. This creates a here-and-now social situation which unfolds in real time. Humans are social animals, who are naturally more alert and vigilant in actual social situations.

What makes the lecture a social event is the potential for two-way communication – mainly the visual link of eye-contact between lecturer and audience. The situation of real time social communication makes students spontaneously more vigilant than when alone with a book or computer, because a student’s failure to pay attention can be observed. By contrast, in a very large lecture auditorium (or when electronic media are used to transmit a lecture remotely) the lecturer cannot maintain eye-contact with all members of the audience. Remote students are not participating in the here-and-now social event: they are excluded from the lecture situation – they might as well be watching TV.

A properly-conducted lecture also exploits the psychological disposition to attend to persons of authority in social situations [6]. In effect, the formal lecture is a mutually beneficial ‘collusion’ between class and lecturer. The structure of a lecture theatre enables a situation in which a group’s attention is focused on the lecturer, and this artificially generates authority in the lecturer. Humans have evolved to attend and remember the words of authoritative individuals. The collusion is that a class of students implicitly, by their silent attention, awards temporary authority to the lecturer (authority which happens to be gratifying for the lecturer) for the purpose of making learning more effective (which is gratifying for the students – and is the aim of the exercise).

A further aspect is that lectures should where possible be given as a whole course – not as one-off events – and by a single lecturer – rather than by a team. It needs repeated interactions for a relationship of trust to build up between lecturer and class – and only when trust is established (if it is established) will students learn effectively.

It is precisely because the authority structure of a formal lecture is so powerful an instrument for focusing attention and improving learning that the lecture medium can be abused for propaganda purposes – for example by political or religious orators who orchestrate mass-meetings or rallies. Because they so effectively exploit human psychology, lectures are intrinsically a form of imposition by one upon the many. There may need to be safeguards, such as an explicit and externally approved curriculum, to prevent the lecture situation being used to pursue non-educational goals.


Scientists, who usually have something to teach which is worth learning, should feel more confident about the value of lecturing and the appropriateness of the method. Students are not being fobbed-off with an inferior medium when lectures are the focus of teaching, nor should the spoken lecture be seen as secondary to the provision of written handouts or transcripts.

So, lectures should not be perceived as redundant elaborations on a text. On the contrary, good lectures cannot be missed without loss, texts are there to support what is spoken, and it should be a clear educational advantage for students to attend lectures.

Furthermore, lecturers should resist the temptation to make lectures more entertaining by over-using ‘visual aids’. Since lectures are primarily ‘aural’, the visual material should generally be appropriate for students’ to record in lecture notes during the actual lecture period – which usually means simple summary sentences, tables and diagrams.

Lectures should be enjoyable, but should not strive to be entertaining as their major goal; lectures ought to be compelling and memorable rather than amusing and diverting. And – because students learn to trust their teachers only gradually – to be educationally effective, lectures should be delivered as a course, not as one-off interactions.

Lectures retain a major educational role because they exploit evolved human psychology to make learning easier and more effective compared with electronic and textual media. Instead of trying to phase-out lectures, we should strive to make them better. And, if the university teaching of science as a general education is to expand in the future [2], it is important to make learning science as easy as possible.


[1] B.G. Charlton, Science school and culture school: improving the efficiency of high school science teaching in a system of mass science education, Med Hypotheses 67 (2006), pp. 1–5. SummaryPlus | Full Text + Links | PDF (75 K) | View Record in Scopus | Cited By in Scopus

[2] B.G. Charlton, Science as a general education: conceptual science should constitute the compulsory core of multi-disciplinary undergraduate degrees, Med Hypotheses 66 (2006), pp. 451–453. SummaryPlus | Full Text + Links | PDF (63 K) | View Record in Scopus | Cited By in Scopus

[3] B.G. Charlton and P. Andras, Universities and social progress in modernizing societies: how educational expansion has replaced socialism as an instrument of political reform, Crit Quart 47 (2005), pp. 30–39. Full Text via CrossRef

[4] M. Trow, Some consequences of the new information and communication technologies for higher education. In: K. Roberts and F. Webster, Editors, The virtual university? Information, markets and managements, Oxford University Press, Oxford (2002), pp. 301–317.

[5] H. Brody, The other side of Eden: hunter-gatherers, farmers and the shaping of the world, Faber, London (2002).

[6] J.H. Barkow, Prestige and culture: a biosocial interpretation, Curr Anthropol 16 (1975), pp. 553–572.