Aristotle said that there were three key elements of rhetoric. One was ethos, or ‘the speaker's power of evincing a personal character which will make his speech credible.’

The other two were:

Logos - the speaker’s power of proving a truth, or an apparent truth, by means of logical, persuasive argument. The obvious English word stemming from this is logic, plus the suffix – ology added to the study of certain subjects (e.g. psychology, zoology, pathology, meteorology etc.)

Pathos – the speaker’s power of stirring and connecting with the emotions of his audience. Think of the English words empathy or sympathy.

A speaker who concentrates on one of these at the expense of the other is only engaging half of his audience's brains. Logic engages the left side of their brains, the half that responds to logic, organisation, rationality, process, systems and data. Emotion engages the right side, the half that responds to visual imagery, creativity, human interest, empathy and imagination

If we take these two terms and use them as axes, we create a matrix as shown below which has four basic presentational styles.

Style number one is low on both emotion and logic; I call such speakers 'Planks' because they have all the appeal of a piece of wood. They stand motionless behind lecterns and read from a prepared script without even looking at the audience in a dull (and often very fast) monotone.

A cardboard cutout could do the job just as well. One of my lecturers at university had this tyle. He was an acclaimed expert in his field and had written 'the' book on his subject, and all he would do each time we had him (double slot - 90 minutes of hell) was read straight from the book in a deep, dull, monotonous voice, without ever looking up.

He may have been a brilliant academic, but he was without doubt the worst lecturer I have ever encountered. As he never added any insights or extra information and as I already owned his book, he simply sent me straight asleep. That is, for the first three weeks. After that I just skipped his lectures.

Style number two (which engages the left-hand side of the brain) is high on logic, structure and process but low on emotion. I call such speakers 'Analysts' because they tend to be very analytical by nature.

A good example is Gordon Brown, the British Prime Minister. He always uses a lectern, standing motionless behind it, and has an extremely serious demeanour. He rarely smiles, and uses very little body language, either facially or with hand gestures. He relies on facts and data to get his points across, and appears uncomfortable on the rare occasion his scriptwriters give him some 'human interest' material to use. His voice seldom varies in terms of pace, volume, pitch or intonation.

This speaking style has a number of strengths, which are listed in the left-hand column to the left.

However, when these strengths are overdone and taken to excess, they become a weakness, as shown in the right-hand column. Thus 'precise' can be seen as 'nit-picking', and 'analytical' as 'anal', and so on.

When this happens, such speakers can come across as wooden, robotic and boring.

Style number three (which engages the right-hand side of the brain) is high on emotion, energy and impact but low on logic and structure. I call such speakers 'Showmen' because they tend to be very impactful and 'showbizzy' by nature.

A great example is Anthony Robbins, the American motivational guru (if you don't know who he is, he played himself in the movie Shallow Hal and was the guy who hypnotised Jack Black in the elevator). He hits the stage like a tornado, and is packed full of energy and expressive body language, both facially and with hand and arm gestures. He hardly ever uses a lectern, preferring to stride purposefully across the stage. He smiles often and gets his points across by using anecdotal evidence and talking about people and relationships. His voice varies constantly in terms of pace, volume, pitch and intonation.

Another example would be Barack Obama ((click here for a selection of his speeches), although he is a much more reserved version than Robbins. Despite his ability to connect with his audience on an emotional level, his speeches are often criticised for their lack of concrete content , and he is accused of being 'all style and no substance.'.

The 'Showman' style has a number of strengths, again listed in the left-hand column to the left.

However, when these strengths are overdone and taken to excess, they also become a weakness. Thus 'energetic' can easily be seen as 'over the top', and theatrical' as 'flash', and so on.

In their determination to entertain, when this happens such speakers can come across as someone who is egotistical and wants to bask in the adoration of the crowd

Style number 4 is high on both logic and emotion, contains the best of styles 2 and 3 and engages both sides of the brain. I call speakers with these styles 'Orators'; their presentations and speeches are well thought out and logically structured, but are also delivered in a way that engages the audience's emotions. They use both facts and data and visual imagery and human interest.

Examples Ronald Reagan or Tony Blair (on a good day, such as when delivering his London Bombing Speech to the Labour Party Conference; at other times his speeches could be 100% bad Showman, consisting of nothing more than a long list of unconnected cliches and soundbites).

In other words, they use Whole-Brain Presenting™. At Speak Like A Pro we teach this on our two-day advanced presenting and public speaking skills seminars using the concept of Emotional Teleology™. Teleology is based on the Greek word 'telos' meaning 'end' and is the study of things with the end in mind. When applied to presenting and public speaking, it means starting with your objective and working backwards, so that every single aspect of the presentation relates to it - the structure, opening, close, script, visual aides, anecdotes, humour and points of human interest.

The adjective 'emotional' is applied to it because the delivery style, which uses anecdotes, humour, visual imagery and human interest to get the points across as well as facts and data.

The result is a presentation that is not only perfectly crated to achieve your objective, but is also delivered in an interesting, engaging and memorable way. In other words, a presentation that appeals to both sides of the brain and massively increase your chances of achieving your objective.