The first bite of an essay

Don't know about you, but I find the first taste of food to be the best. It's probably a combination of the hypothalamus getting its way, some neural adaptation thereafter and a bit of the primacy effect, if we are stripping down and getting really geeky. Science aside, I probably make my "Mmm, great", "Yeah, not bad" or "Ergh! Who cooked this?" after this first bite or two. It's the same with essays: the introduction will give your reader an immediate flavour for your mark and they'll spend the rest of the time they're reading making tweaks to that figure (this is what every lecturer I have ever asked has intimated).

If you start poorly your essay will have to work damn hard to improve the marker's opinion of it. Send them reeling with a confusion blow from the start and they don't really recover. On the other hand, a punchy, crisp and explicit introduction will elevate the marker's opinion of you such that occasional weaknesses are excused and any confusion you bestow upon the reader is lessened because they still have the thrust of your argument ringing in their ears from the introduction.

I think the perfect introduction has four parts and is super-concise (fewer than 150 words)

1. A sentence to introduce the general area.
2. A sentence or two to introduce the specific issue at hand.
3. An idea of the route you are going to take or any definitions that need settling
4. A punchy statement of where you are going to end up.

I'll illustrate these with an example introduction to this mock question:

"Who is the best fighter in the University of Bristol Experimental Psychology Department?"

(1) Hand-to-hand combat between psychology lecturers is common (2) Yet, the question of who is the best fighter at the University of Bristol remains largely unspecified. (3) By evaluating a large corpus of fight data and accounting for the heavy bias in Stollery's (2007) meta-analysis (towards Stollery) (4) it will be argued that although Hood (weapon: short-sleeved shirt), Scott-Samuel (weapon: the bitingly acerbic comment) and Mike from CSG (weapon: dangerous mugshot) were strong, Bowers emerges as the clear winner with his ability to 'seriously confuse from fifty feet'.

Or more seriously:

Which theory do you think offers the best account of consciousness?

(1) Consciousness presents science with its most frustrating problem because it is both so familiar but so tough to explain; (2) nevertheless, a number of theories have been put forward. (3) By evaluating some of these theories against their ability to accurately and parsimoniously explain a large corpus of evidence, (4) a number will be rejected in deference to an adaptive representational model of consciousness, where temporal information integration is fundamental.

So, remember the reader's first taste of your essay is very important. Given that they will probably have read lots of essays before getting to yours, 'Tango slap' your reader into sitting up and paying attention to your sharp, punchy start.