One of the fundamental ways the environment has changed locally must be the level of information that we are now able to process. Namely, since writing was invented, we've been able to consume (I would suppose) far more knowledge from far more sources. But, after all, since writing is just like a mimic of speech that we were originally "designed" for, I can't imagine the modern environment is so much different for our built in algorithms for writing. And similarly for many other "modern" aspects of life.

Edit: Interestingly, I suppose books and written information have essentially developed in civilization as a response to the weaknesses of the evolved brain. Thus, many of the deficiencies in our cognitive operations have actually been attacked by civilization. Insofar as the brain was not properly designed, the modern environment has largely been a source of positive, external cognitive optimization/reorganization.

One might propose that the environment has actually become far less challenging in modern times; certainly I haven't had to hunt and kill for food anytime in recent memory. Now, I can live far longer, with much less (positive) stress, I can smoke and drink and damage my mind at will, I have the express ability to become morbidly obese and mentally unhealthy, and so on. I can freely read and absorb widely disseminated propaganda from sources like Hitler, in maybe the worst case scenario. Perhaps the environment has been effectively weakening our internal algorithms through this kind of under usage and exploitation, rather than through any incidental non-optimization.