I am not sure why you are being downvoted, as the author himself first says:

The best research in social psychology is as well-supported as anything in physics or biology, and much more intuitively comprehensible.

And then he follows it up with:

Social psychology experiments in the laboratory tend to throw up spectacular mind-boggling effects. Many of these fail to replicate and are later discredited. The ones that do replicate are not always generalizable – sometimes an even slightly different situation will remove the effect or create exactly the opposite effect. The effects that remain robust in the laboratory may be too short-lasting or too specific to have any importance in real life. And the ones that do matter in real life may respond unpredictably or even paradoxically to attempts to control them.