From Bruce Bennett:

Re: Are people getting dumber?: It could as well be argued that intelligence linked with formerly debilitating genetic illnesses can now be passed on genetically (i.e. a Steven Hawking - like example) - whereas at the time period that Crabtree supposes maximal intelligence, all the IQ in the world would not help a less-than-robust specimen...  I don't see a clear argument for 'genetically getting dumber' by lack of selection process.

I think current IQ scores reflect the society more than any sudden genetic trend :)