Een stopped (Bissett Logan, 2014). We categorized each subject’s strategy using the decision matrix discussed in Bissett and Logan (2014, p. 457): If subjects use the `Stop then Discriminate’ strategy, signal espond RT should be shorter than no-signal RT, but PD0325901 dose 3-MethyladenineMedChemExpress 3-Methyladenine invalid-signal RT should be longer than nosignal RT (because subjects have to restart the response on invalid-signal trials). If subjects use a `Discriminate then Stop’ strategy, and the decision to stop or not interferes with going (i.e. dependence between go and stop), both signal espond RT and invalid-signal RT should be longer than no-signal RT. If they use the `Discriminate then Stop’ strategy, and the decision to stop or not does not interfere with going (i.e. independence between go and stop), signal espond RT should be shorter than no-signal RT, and no-signal RT and invalidsignal RT should be comparable. To determine whether signal espond and invalid-signal RTs were longer than no-signal RT, we calculated for each subject the 95 confidence interval around their mean no-signal RT; their signal espond and invalid-signal RTs were considered to be different from their no-signal RT if the signal RTs did not fall within this confidence interval. The outcome of this analysis appears in Fig. 4. Most subjects in the consistent-mapping condition (in which the discrimination was easiest) seemingly used the `Stop then Discriminate’ strategy, whereas most subjects in the variedmapping condition (in which the signal discrimination was hardest) seemingly used the `Discriminate then Stop’ strategy (Fig. 4). We observed this pattern of results in each experiment. When we combined the data of all experiments, Fisher’s Exact Test for Count Data revealed that the distribution of strategies across the varied-mapping and consistentmapping groups was significantly different (p < .001). From a strategy point of view, this pattern of results seems very odd. In the varied-mapping group, the signal-validity mapping constantly changed, so the demands on the rule-based system remained high throughout the whole experiment. Presumably, this should have encouraged subjects in this group to use a `Stop then Discriminate' strategy rather than a `Discriminate then Stop' strategy. After all, `Stop then Discriminate' allows fast stopping and reduces overlap between demands of the stop and the go task on the rule-based system. Reducing the demands should be more important when they are high, so the varied-mappingAuthor Manuscript Author Manuscript Author Manuscript Author Manuscript3Responses on invalid-signal trials could also be stopped in a bottom-up fashion. Several studies have indicated that stopping can be primed by stimuli or stimulus features that were previously associated with stopping (Bissett Logan, 2011; Giesen Rothermund, 2014; Rieger Gauggel, 1999; Verbruggen Logan, 2008a,b, Verbruggen, Best, Bowditch, Stevens, McLaren, 2014; Verbruggen, Logan, et al., 2008).Cognition. Author manuscript; available in PMC 2016 April 08.Verbruggen and LoganPagegroup should prefer the `Stop then Discriminate' strategy more than the consistent-mapping group. We found the opposite.Author Manuscript Author Manuscript Author Manuscript Author Manuscript3. General discussionPerformance in various response inhibition tasks is usually described as an independent race between a go process and a stop process. In the past three decades, several studies have indicated that go and stop processing are indeed indepe.Een stopped (Bissett Logan, 2014). We categorized each subject's strategy using the decision matrix discussed in Bissett and Logan (2014, p. 457): If subjects use the `Stop then Discriminate' strategy, signal espond RT should be shorter than no-signal RT, but invalid-signal RT should be longer than nosignal RT (because subjects have to restart the response on invalid-signal trials). If subjects use a `Discriminate then Stop' strategy, and the decision to stop or not interferes with going (i.e. dependence between go and stop), both signal espond RT and invalid-signal RT should be longer than no-signal RT. If they use the `Discriminate then Stop' strategy, and the decision to stop or not does not interfere with going (i.e. independence between go and stop), signal espond RT should be shorter than no-signal RT, and no-signal RT and invalidsignal RT should be comparable. To determine whether signal espond and invalid-signal RTs were longer than no-signal RT, we calculated for each subject the 95 confidence interval around their mean no-signal RT; their signal espond and invalid-signal RTs were considered to be different from their no-signal RT if the signal RTs did not fall within this confidence interval. The outcome of this analysis appears in Fig. 4. Most subjects in the consistent-mapping condition (in which the discrimination was easiest) seemingly used the `Stop then Discriminate' strategy, whereas most subjects in the variedmapping condition (in which the signal discrimination was hardest) seemingly used the `Discriminate then Stop' strategy (Fig. 4). We observed this pattern of results in each experiment. When we combined the data of all experiments, Fisher's Exact Test for Count Data revealed that the distribution of strategies across the varied-mapping and consistentmapping groups was significantly different (p < .001). From a strategy point of view, this pattern of results seems very odd. In the varied-mapping group, the signal-validity mapping constantly changed, so the demands on the rule-based system remained high throughout the whole experiment. Presumably, this should have encouraged subjects in this group to use a `Stop then Discriminate' strategy rather than a `Discriminate then Stop' strategy. After all, `Stop then Discriminate' allows fast stopping and reduces overlap between demands of the stop and the go task on the rule-based system. Reducing the demands should be more important when they are high, so the varied-mappingAuthor Manuscript Author Manuscript Author Manuscript Author Manuscript3Responses on invalid-signal trials could also be stopped in a bottom-up fashion. Several studies have indicated that stopping can be primed by stimuli or stimulus features that were previously associated with stopping (Bissett Logan, 2011; Giesen Rothermund, 2014; Rieger Gauggel, 1999; Verbruggen Logan, 2008a,b, Verbruggen, Best, Bowditch, Stevens, McLaren, 2014; Verbruggen, Logan, et al., 2008).Cognition. Author manuscript; available in PMC 2016 April 08.Verbruggen and LoganPagegroup should prefer the `Stop then Discriminate' strategy more than the consistent-mapping group. We found the opposite.Author Manuscript Author Manuscript Author Manuscript Author Manuscript3. General discussionPerformance in various response inhibition tasks is usually described as an independent race between a go process and a stop process. In the past three decades, several studies have indicated that go and stop processing are indeed indepe.
