At a theoretical level, one can also find differences between the negative priming and the DPE. There are two classes of theories regarding NP (as well as theories that combine elements of both classes; see Tipper,
2001). The first account, the active (or persistent) inhibition theory (as originally proposed by Tipper,
1985), argues that the color-based suppression of the “distractor” on trial
N − 1 persists to trial
N and is associated with the current-target stimulus (i.e., a stimulus with the same identity as the previously ignored distractor, but presented in the to-be-attended color). According to this account, the inhibition is associated with the specific identity of the recently rejected stimulus (above and beyond the featural inhibition associated with the to-be-ignored color). In contrast, in the current study, the inhibition is constrained to the feature (or category) level. We have also previously demonstrated that the inhibition is constrained to the “search-relevant” feature dimensions of the task (Levinthal & Lleras,
2008): inhibition is only observed along feature dimensions that are used to define the oddball-status (such as stimulus identity or shape). In other words, the inhibition does not transfer to other dimensions of the “rejected” stimuli (e.g., response features). The second account of NP, the episodic retrieval theory (originally proposed by Neill, Valdes, Terry, & Gorfein,
1992) argues that NP arises because when selecting a target, there is automatic re-activation of previously response-related information associated with this stimulus. In the “previously ignored” condition of NP, this re-activation produces a response conflict that slows responses because the last action associated with this stimulus was a “no-go/no-response” action. Variants of this theory have gathered support lately (e.g., Rothermund, Wentura, & De Houwer,
2005; Stahl & Gibbons,
2007). According to this class of theories, the locus of inhibition is at the response-selection/preparation stage of processing. In contrast, various demonstrations have shown that the DPE is not a response-level effect (e.g., Lleras et al.,
2008). In particular, using electrophysiological recordings of participants during a spatial DPE task, Shin et al. (
2008) showed that the spatial DPE correlated with differences in the latency of the N2Pc (an attentional component) and found no differences in the LRP (a marker of response preparation that is sensitive to conflict during response-selection processing). In sum, the extant data on the DPE are inconsistent with current theories of NP. However, one could still argue that current theories of NP have failed to capture important aspects of the NP phenomenon and that paradigm-driven investigations of NP and the DPE are responsible for the apparent dissociation between these two effects. After all, these two effects are both examples of “transfer-inappropriate processing” (Neill & Mathis,
1998). Thus, it is possible that further investigations on these two phenomena might yet lead to a better understanding of this larger class of behavioral effects and possibly shed light on the role of inhibitory processing observed in experience-based effects.