We present a joint theoretical and experimental investigation of the absorption spectra of silver clusters Agn (4<=n<=22). The experimental spectra of clusters isolated in an Ar matrix are compared with the calculated ones in the framework of the time-dependent density functional theory. The analysis of the molecular transitions indicates that the s-electrons are responsible for the optical response of small clusters (n<=8) while the d-electrons play a crucial role in the optical excitations for larger n values.