Interventions in the behavioral invariance characterizing autism by the differential reinforcement of topographical variation (DRV) have not reliably produced clinically significant levels of response-form diversity. Consistent with the prevailing account that the discrimination of recent and current behavioral topographies is not necessary (and indeed is likely to impede) the effectiveness of DRV, ‘lag’ schedule and related interventions often lack visual, auditory and instructional prompts indicating the relation between current and recently-reinforced topographic variants. Moreover, such prompting of self-discrimination would further complicate labor-intensive lag-schedule interventions. Accordingly, best practice recommendations for the use of ‘lag’ contingencies have discouraged the use of stimulus control technology except in cases in which a simple two-term DRV contingency has failed—this despite multiple comparative reviews indicating that prompts might facilitate DRV intervention in behavioral stereotypy. The utility of such best-practice recommendations was tested within subjects. High-functioning autistic and neurotypical children were initially exposed to unassisted DRV of the serial pattern of vocal naming of static object images. Consistent with the literature, modest increases in topographic variance plateaued at non-adaptive stereotypic levels (mean = ‘lag’ 1.7); performance subsequently tended to deteriorate. Significant increases (mean = ‘lag’ 9.6) in response-form diversity ensued with the temporary, performance-titrated provision of contingency-specifying instructions coupled with synchronized audio-visual event patterns uniquely associated with each vocal pattern variant, increasing the probability of discrimination of topographical repetition and the evocation of disparate patterning. Adaptive levels of vocal diversity generalized to novel stimuli without further prompting. Digital automatization freed practitioners from otherwise unmanageable procedural demands. Keywords: Αutism, vocal stereotypy, operant variability, ‘lag’ schedule of reinforcement, precurrent mediating behavior, delayed oddity matching-to-sample