. Structure: essays should make an argument: your essay should have a point and reach a conclusion, even if tentative, and you should try to convince the reader that your point is correct. This is the most important single point in writing a good essay. It will help you make it well organized, and well-written. Clarity of thought and argument provide the necessary basis for a clear writing style. Thus, just like making a legal case in the courtroom, you follow a logical progression, using data or evidence to support each step of your argument, until you reach a logical conclusion. What counts as a good argument, or a solid conclusion? There is room for considerable creativity here, depending on the topic. It is easier to say what does not count as a good conclusion. For example, you should never just review a study or studies, and conclude that "more work is necessary". More work is always necessary, and YOUR work in this essay is to reach a more substantive conclusion than that. A recapitulation of some experiments with no substantive conclusions does not constitute a good essay, however accurate. State the point of the essay in the introduction, using the first person (I argue, I believe, etc.). For example: "I will argue here that the frustration/aggression hypothesis is based on an oversimplified and inadequate psychological model, and is thus unable to explain most cases of prejudice that have been analyzed". 2. It is key to back up each crucial point that you make with data. Don't just cite the study, but briefly describe its key result(s) in a sentence or two, and explain, explicitly, why this supports your point. Any statements of nonobvious fact (e.g. "monkeys can follow gaze", or "dopamine is necessary for motor function") should be followed by a reference (even if only to a textbook). Each piece of data should be cited at the appropriate place in the argument (and not repeated excessively in other less appropriate places). Avoid unnecessary data. How many of a species live where, what it eats, etc. are typically NOT relevant. Specific statistical values, like means or p values, are almost never appropriately cited in a review. Also, don't describe all the details of any experiment, only those that are relevant to the question you are addressing. On the other hand, ALWAYS cite relevant data. If something is relevant to your point, you must cite it (even if it goes against your argument!). Finally, don't say "This treatment appeared to have an effect" - either there was a statistically significant effect (in which case you say "there was a significant effect of x on y) or it didn't ("there was no effect of x ") 3. Proof: Note that the logic of scientific discovery is that of generating a list of possibilities (postulating hypotheses) and then doing experiments to test them. We proceed by rejecting false hypotheses, rather than proving true ones. If we've rejected all of the plausible hypotheses but one, we consider the one left standing to be the best one, so far, but we don't consider it proven until a large amount of data converges on that as the only remaining possibility, from many labs and with many different techniques. So it is very unusual for a single empirical study to "prove" a particular hypothesis. It may be consistent with that hypothesis, but doesn't prove it.