An example system includes an analyzer to identify first activity in first neuro-response data, the first activity generated in response to exposure of a subject to a first stimulus prior to exposure to an advertisement or entertainment; identify second activity in second neuro-response data, the second activity generated in response to re-exposure of the subject to the first stimulus after to exposure to the advertisement or entertainment; calculate a differential event related potential measurement; and calculate a differential event related power spectral perturbation. The example system includes a resonance estimator to determine a subject resonance measurement to the advertisement or the entertainment based on the differential event related potential measurement and adjust at least one of the subject resonance measurement or the differential event related potential measurement based on the differential event related power spectral perturbation to generate an adjusted subject resonance measurement.