Spike timing dependent plasticity (STDP) is an important neural process that enables biological neural networks to learn by strengthening or weakening synaptic connections between neurons. This work presents simulation results and post-silicon experimental data that demonstrate for the first time the possibility of tuning the on state resistance of a type of emerging resistive memory device known as conductive bridge random access memory (CBRAM) in accordance with the biological STDP rule for neuromorphic applications. STDP behavior is demonstrated for CBRAM devices integrated with CMOS spiking neuron circuitry through back end of line post-processing for different initial resistance values and spike durations.