What metaphors help us to understand the functions of reason and emotion?

Plato argued that we can only be masters of ourselves if reason, the ‘human charioteer’ is able to control the dumb beasts of passion:

‘Now the winged horses and the charioteers of the gods are all of them noble and of noble descent, but those of other races are mixed; the human charioteer drives his in a pair; and one of them is noble and of noble breed, and the other is ignoble and of ignoble breed; and the driving of them of necessity gives a great deal of trouble to him. ... The right-hand horse is upright and cleanly made; he has a lofty neck and an aquiline nose; his colour is white, and his eyes dark; he is a lover of honour and modesty and temperance, and the follower of true glory; he needs no touch of the whip, but is guided by word and admonition only. The other is a crooked lumbering animal, put together anyhow; he has a short thick neck; he is flat-faced and of a dark colour, with grey eyes and blood-red complexion; the mate of insolence and pride, shag-eared and deaf, hardly yielding to whip and spur’ (‘Phaedrus’).

Plato’s metaphor seems to have provided the basis for an influential model of human flourishing which puts reason (or rationality) on a pedestal and views the emotions as crude and primitive. In his book, ‘How We Decide’(2010), Jonah Lehrer links Plato’s metaphor to Cartesian philosophy and notes that Freud used a similar metaphor in which the horse (id) provides the locomotive energy and the rider (ego) determines the goal and guides his powerful mount towards it (p.10-12).

However, Lehrer points out that this classical theory is ‘founded on a crucial mistake’: ‘What we have discovered when we look at the brain is that the horses and the charioteer depend on each other’ (p. 13). ‘When we are cut off from our feelings, the most banal decisions become impossible. A brain that can’t feel can’t make up its mind’ (p.15). We might like to think that reason plays a large role in our decisions, but if our feelings didn’t tell us what we like and dislike we would not be able to make decisions.

Jonathan Haidt has argued similarly that Plato’s metaphor ‘may overstate not only the wisdom but also the power of the charioteer. ... Reason and emotion must work together to create intelligent behavior, but emotion ... does most of the work’ (‘The Happiness Hypothesis’, 2006, p.13).

Haidt has his own metaphor, an elephant and its rider, to explain the relationship between the controlled and automatic systems that determine human behaviour:
‘The controlled system ... is better seen as an advisor. It’s a rider placed on the elephant’s back to help the elephant make better choices. The rider can see further into the future, and the rider can learn valuable information by talking to other riders or by reading maps, but the rider cannot order the elephant around against its will. ... The elephant and the rider each have their own intelligence, and when they work together well they enable the unique brilliance of human beings’ (p.17).

Jonah Lehrer uses a modern aeroplane in his metaphor to explain the functions of the emotional brain and the pre-frontal cortex:

‘To sit in a modern airplane cockpit is to be surrounded by computers. ... These computers are like the emotional brain of the plane. They process a vast amount of information and translate that information into a form that can be quickly grasped by the pilot. ... These computers are so reliable that they perform many of their tasks without any pilot input. ... Pilots are like the plane’s prefrontal cortex. Their job is to monitor these onboard computers, to pay close attention to the data on the cockpit screens. If something goes wrong, or if there’s a disagreement among the various computers, then it’s the responsibility of the flight crew to resolve the problem. ... When the onboard computers and pilot properly interact, it’s an ideal model for decision-making. The rational brain (the pilot) and the emotional brain (the cockpit computers) exist in perfect equilibrium, each system focusing on those areas in which it has a comparative advantage’ (p.256-8).

Which metaphor is best? I doubt whether one metaphor is the best aid to understanding of all aspects of human behaviour, but I think the elephant metaphor is better than the plane metaphor from a personal development perspective. It is possible to think of the rider and elephant as being responsible for their future performance as well as for their current performance. As Jonathan Haidt puts it, ‘virtue resides in a well-trained elephant’ (p.160). I don’t pretend know much about training elephants or their riders but it seems reasonable to suppose that they would have a stronger incentive to learn to work together and to improve their performance if they were held jointly responsible for their behaviour.