Detailed experimental results and results of factorial ANOVAs are shown in Supplementary Fig. 1. Table 2 shows F and p values from ANCOVAs for significant tests taking verbal IQ, non-verbal IQ and processing speed as covariates. There were significant group differences in three measures. First, in the subitizing task counting-range slope was less steep in DD than in controls in the

4–6 number range. This was due to a larger drop in accuracy for number 6 in controls than in DD (see star in Supplementary Fig. 1D). Second, there was a larger congruency effect in DD than in control participants in non-symbolic magnitude comparison (see star in Supplementary Fig. 1F). Third, correct rejection performance was worse in DD than in controls in the

Stop-signal task (see star in Supplementary Fig. 1E). In ANOVAS Inhibitor Library nmr there was an additional marginal group × congruency interaction in the animal size Stroop task due to a marginally larger congruency effect in DD than in controls ( Supplementary Fig. 1B). The trail-making task was scored on a 0–2 scale. Accuracy was practically the same in both groups in both trail-making A/B: All DD participants and all but one control scored maximum on trail-making A (a AZD6244 supplier single control scored 0). Scores were also matched on trail-making B (number of DD/Control participants with particular scores: Score 2: 8/7; Score 1: 2/2; Score 0: 2/3). Importantly, both permutation testing and confidence interval estimation showed that symbolic and non-symbolic slope was a highly non-discriminative parameter between groups. Fig. 3 shows effect sizes. In detail, in the non-symbolic discrimination task the mean ratio effect was −1.75 ± .5% (mean and SE; accuracy for each ratio: 97.2 ± 1.1, 95.6 ± 1.4 and 93.7 ± 1.6%) in the DD group and −1.70 ± .4% in the control

group (accuracy for each ratio: 97.7 ± .9, 95.2 ± 1.8 and 94.3 ± 1.8%). In the symbolic discrimination task the mean distance effect was −3.26 ± 1.4% Florfenicol (distance 1 minus distance 4) in the DD group and −5.24 ± 1.4% in the control group (accuracy for each level of distance: DD: 91.5 ± 1.9 and 94.8% ± 1.3; controls: 89.0 ± 2.3 and 94.2 ± 1.6%). Fig. 3B summarizes main findings in RT with permutation testing and t statistics and bootstrapped 95% confidence intervals for effect sizes. Detailed experimental results and results of factorial ANOVAs are shown in Supplementary Fig. 2. Table 3 shows F and p values from ANCOVAs for significant tests taking verbal IQ, non-verbal IQ and processing speed as covariates. There were significant group differences in four measures. First, there was a larger facilitation effect in the numerical Stroop task in DD than in control participants ( Supplementary Fig. 2G). The negative effect means that RT sped up more in the congruent relative to the neutral condition in DD than in control participants.