Psychology is a curious case. At least the perception about psychology was that with mere 20-25 days prep, one can score around 140-150 marks but things are changing now. 2012's paper was too easy and 2013's paper was quite tough. Selective study of few chapters nor 10 years' past papers won't suffice, not anymore now.

One has to be able to relate the concepts and fundamentals of each chapter to the remaining ones. For that, you need to consult at least 2 books, well-written ones, go deep into the subject, consult resources internet and grasp the basics and then build on it. Selective study of few chapters or 10 years' past papers won't suffice, not anymore now.

As of psychology, it has been scoring as of now, but result of 2013 is not yet out, so tough to say how it fares in 2013. The perception is that it might be on low scoring side and this assumption is based on 2 facts:
a- Paper of 2013 was a 180 degrees shift compared to those of past 10 years
b- Date sheet was shuffled in a way that aspirants who had opted histories, Socio & Journalism, and geography, the most commonly opted subjects, they had much less time to prepare for psychology
I personally believe that these events portend moderate to low scores for psychology in 2013 and it is very much possible keeping in view FPSC’s knack to smack the so called formula- subjects , the subjects which draw aspirants’ near crazy rush due to good scoring trend. So in my opinion it would be wise to wait for 2013's written result to make the final decision. Till then, complete the rest of your optionals. If it remains low scoring, which will be the first time ever in the history of Psychology, it will not be very prudent to go with psychology in 2014.

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"And how can man die better than facing fearful odds, for the ashes of his fathers, and the temples of his Gods?"