What can reduce the cognitive abilities in a common workplace?
One of the most significant factors impairing cognitive abilities in a typical office environment is the noise. It is well-known that quiet environment is essential for good concentration. For instance, WHO recommends school classrooms should have noise level as low as 35 dB during classes. Yet a typical office environment can be as loud as 70 dB, which is about 30-50 times louder.

There are loads of articles describing the effects of different levels of noise on various cognitive abilities, which inevitably show that noise above 60-65 dB has a significant impact on mental activity, and noise above 75 dB has a lasting effect which can be measured 4 hours after the exposure. For reference, most public transport is louder than that, and a subway can be as loud as 95 dB.

It is well known that private offices (which reduce the noise quite a bit) can boost productivity significantly. Unfortunately, they are too pricey, or at least are seen as such, to become widespread.