Tom has written an excellent article for The Psychologist on the not-so-obvious findings in psychology which has just been made freely available.
There are certain predictable responses you get if you introduce yourself as a psychologist.
The most common is “are you analyzing me?”, followed by “can you read my mind?”. The best answer to both, of course, is ‘sometimes’.
Occasionally, a bright spark will tell you “psychology, well, it’s just obvious isn’t it?”, which, to be frank, I wish it was. But sadly, it’s fiendishly complicated.
Tom’s article gathers a whole bunch of counter-intuitive research findings for exactly such situations:
I used to keep a stock of ‘unobvious’ findings ready to hand for occasions like this. Is it really obvious that people can be made to enjoy a task more by being more poorly paid to recruit for it (cognitive dissonance: Festinger & Carlsmith, 1959)? That a saline solution can be as effective as morphine in killing pain (the placebo effect: Hrobjartsson, 2001)? That students warned that excessive drinking is putting many of their peers at risk may actually drink more, whereas advertising the fact that most students don’t drink, or drink in moderation, is the thing that actually reduces binge drinking (Perkins et al., 2005)? That over a third of normal people report having had hallucinations, something we normally experience solely with mental illness or substance abuse (Ohayon, 2000)? Or that the majority of ordinary Americans could be persuaded to electrocute someone to death merely by being asked to by a scientist in a white coat (Milgram, 1974)?
There’s many more great examples, including touching on the cognitive bias that leads people to think they understand more than they do when they have little knowledge.
Priceless stuff.
Link to article in The Psychologist on the ‘obvious’.
Mind Hacks 
There are some inaccuracies in that report:
“Other notions that have been challenged include that children need to be taught language (Chomsky, Pinker), that parenting style has a significant effect on child development (Rich-Harris)”
I would not exactly call those established conclusions in psychology. Chomsky/Fodor/Pinker have been soundly challenged by other views. Most people do not agree with them (that the mind is composed of innate modules for language and math and chess and so forth).
And Judith Rich-Harris’ research does not say that parenting style has no impact on child development. That would suggest that for example beating your child everyday has no effect on that child’s development. Her opinion (not research) is that “common” parenting styles and techniques have changed in the past 50 years (like less spanking), but child development has not improved as a result (more teen suicides, depression, etc.). Of course that completely ignores the fact that society has changed a bit since the 1940s.