Some applicants may ramble on about themselves in a manner that may appear self-indulgent and not very appealing to the committee. Remember, this is an application essay, not an autobiography. Conversely, some applicants tend to say too little, perhaps hesitating to promote themselves too explicitly or not knowing what about themselves would be interesting to people whom they don't know. In such cases, perhaps focusing more on what you want to do than on what you have already done (let your record speak for itself) may help in getting beyond self-inhibition.
The modern psychology began with Rene Descrate (1596-1650) whose viewpoint was that reflection and introspection are investigatory methods, which are more superior to observation. He believed that the ideas of body-mind are dual and innate to knowledge. John Locke believed that interaction between body and mind in equal relationship between aspects of same unified phenomenon. Immanuel Kant reconciled the viewpoints of body and mind, and trying to relate between the mind and body and whether the mind is in control. In conclusion, contemporary psychology grapples with the same issues physiologist and philosophers grappled with as most of them concur that the mental processes and human behavior harmonize to adopt to the environment.
It’s as well to keep in mind what you should not be doing. Do not introduce lots of fresh evidence at this stage, though you can certainly introduce the odd extra fact that clinches your case. Nor should you go on to the ‘next’ issue. If your question is about Hitler coming to power, you should not end by giving a summary of what he did once in power. Such an irrelevant ending will fail to win marks. Remember the point about answering ‘nothing but the question’? On the other hand, it may be that some of the things Hitler did after coming to power shed valuable light on why he came to power in the first place. If you can argue this convincingly, all well and good; but don’t expect the examiner to puzzle out relevance. Examiners are not expected to think; you must make your material explicitly relevant.