Review scores manipulate the opinions of readers by tapping into their psychology, in particular a psychological concept called "priming," said games industry veteran Boris Scheider-Johne.
Priming is a form of quantifying, said Schneider-Johne during his presentation at today's GDC Europe 2013. Citing case studies among behavioralists, he defines this as an implicit memory effect in which exposure to a stimulus influences a response later on; in other words it's a form of recognition memory.
To put that into the context of reviews, users who read a low-scored review are implicitly influenced by that score's number and its negative connotations when later asked for their opinion of the game. The same will naturally go for high scores.
The game review system is "broken by design and psychology"
Despite the apparently significant influence of reviews on readers, those in charge of review writing are largely "self-appointed and not especially gifted," said Schneider-Johne. As a result, Schneider-Johne says it leads to an unfair system "broken by design and psychology."
Within this broken system developers who financially depend on reviews and popular opinion "need to game the system." Success in this case can only be found by developers who rely on word of mouth by building a great product, a "fantastic first 15 minutes," and a "meta-story" that make the experiences easier for users to tell their friends about.
Schneider-Johne is a former Germany-based games journalist who later became the official translator for LucasArts. He currently works at Microsoft but emphasized he is not representing the company during this talk.