Is there semantic conflict in the Stroop task ? Investigation of distinct components of the Stroop effect in the two-to-one Stroop paradigm

By assessing whether semantic (in addition to response) conflict contributes to the Stroop interference effect observed in the two-to-one Stroop paradigm (De Houwer, 2003), the present thesis was aimed at contributing to the ongoing debate about the locus (vs. loci) of the Stroop interference effect. To this end, the two-to-one Stroop paradigm administered with an additional (i.e., color-neutral) baseline was combined with Single-letter coloring and cueing (SLCC) in Chapter 1 and Chapter 4; with healthy aging in Chapter 2; and with variations in Response-stimulus intervals in Chapters 3 and 4. In complete contrast to dominant single-stage response competition models of the Stroop interference effect, results of experiments reported in this dissertation leave no doubt that selection occurs at the semantic level in the Stroop task. The immediate implications for the composite (as opposed to unitary) nature of the Stroop interference effect and other still unresolved issues in the Stroop literature are discussed.