the correlation degree in 122 iron pnictides mainly depends on the electronoccupancy of each orbital and that by doping electrons the correlation decreases monotonically. This is also suggested by ARPES results where the electronic band width of BaCo2As2 is clearlylarger than that in Ba 0.6K0.4Fe2As2. In our previous inelastic neutron scattering experiment on SrCo2As2,the (1/2,1/2) spin excitations were found to persist up to 135 meV and not to split as that in BaFe2As2 in whichtwo peaks can be clearly seen above 75 meV. This is a clue that the magnetic dispersion is indeed hardenedin SrCo2As2 as the magnetic correlation decreases. However, it is not clear whether the spin excitations will split and disperse to zone boundary at higher energ , or simply be more diffusiveand disappear at (1/2,1/2) point. Furthermeasurements on improved SrCo2As2samples are necessary.