I don't know if Nigerians are the smartest people on earth but they sure are smart, Igbo folk in particular. To give an example; back in 1981 I was hiring staff in Warri.
A young (17) Igbo fellow called Sam asked for a job. He was as short as me and very slim so not suitable for laboring work. He was totally full of beans so I hired him anyways to help me with line testing gear.
Sam had had just four years of primary education. About a week in he asked me why I liked the small numbers on the test gear and did not like the big ones. So sitting there under a mangrove I explained voltage, current, Ohms law and the problem with contaminated connections.
About an hour later Sam comes back with a drawing and a handful of batteries. He wanted to know whether there was a way to put the batteries in the geophones so as to push the signal through even with poor connections.
I was gobsmacked. An hour after hearing of Ohm's law for the first time he'd dreamt up the concept of a pre-amplifier. I had an electronics workshop so I took Sam into it and started with the math and electronics. He lived in that lab. He went from Euclid to Leibniz in less than a month. Six weeks in he was using spectrum analysers to control inter-modulation between multiple radio transmitters.
In the eleven months we worked/learnt together Sam got to about associate degree level. He set up an electronics store after.
Some damn smart folk in the Delta.