It is not true that our attention or focus on a particular item can last longer than about 12 seconds. I am claiming that 12.6 seconds is the maximum duration of our attention span on any particular item. We can force ourselves to switch attention before the brain does it for us automatically. It takes effort on our part to refocus our attention on an item of interest. Microsoft released a study in 2015 that found that our average attention span went from about 12 seconds in the year 2000 to 8 seconds. They attributed it to us being bombarded by too much info which causes us to switch our attention more often.
It is possible to perform an experiment to calculate the attention switching speed. Some experiments have concluded that attention shift is extremely fast, less than 50 ms even though they were testing visual attention shift via eye movements. The 35 millisecond interval is the claim I am making. It’s a falsifiable claim and thus scientific.
A few links:
To do a proper experiment would require that the subject undergoes a fast fMRI test. But fMRI speeds are probably too slow. A more accurate test would require the use of electrodes implanted directly in the brain.