The DSTP model is a formal (diffusion process) model of response selection that also includes the interaction of early and late stimulus-selection processes. It is assumed that attentional selectivity increases discretely during response selection rather than gradually.
Hübner, R., Steinhauser, M. & Lehle, C. (2010). A dual-stage two-phase model of selective attention. Psychological Review, 117, 759-784. <pdf>
Hübner, R., & Pelzer, T. (2020). Improving parameter recovery for conflict drift-diffusion models. Behavior Research Methods. <Open Access>
Hübner, R., & Töbel, L. (2019). Conflict resolution in the Eriksen flanker task: Similarities and differences to the Simon task. PloS one, 14(3), e0214203. <Open Access>
Dambacher, M., & Hübner, R. (2015). Time pressure affects the efficiency of perceptual processing in decisions under conflict. Psychological Research, 79, 83-94. <pdf>
Hübner, R. (2014). Does attentional selectivity in global/local processing improve discretely or gradually?Frontiers in Psychology, 5. <doi>
Hübner R., & Töbel L. (2012) Does attentional selectivity in the flanker task improve discretely or gradually? Frontiers in Psychology, 3. <doi>
Recently, an R package implementation has been published: see Grange, J. A. (2016). flankr: An R package implementing computational models of attentional selectivity. Behavior Research Methods, 48, 528-541. <doi>