When a few electrons are excited, correlation effects become conspicuous. We present recent progresses on the understanding of electronic correlations for doubly - and triply-excited states of simple atoms. The local minimization of kinetic and potential energies determine correlation eigenmodes which evolve smoothly with the size of the system. This intuitive picture is naturally implemented by the hyperspherical formalism which selects the global size of the many-electron system as the unique radial variable R. Correlation eigenmodes emerge as the eigenstates of the fixed-R hamiltonian and the corresponding eigenvalues define effective potentials governing the system's expansion The hyperspherical analysis of correlation is illustrated on simple systems H-, He, and He-