Table 2. Statistics for One-Sample t Tests of Interference Costs.
| Age group | M | SD | t | p (significance level controlling for multiple comparisons = .008) | Effect size (Cohen’s d) |
|---|---|---|---|---|---|
| Note. C = congruent trial; SI = stimulus incongruent only trial; SRI = stimulus and response incongruent trial. | |||||
| 7-year-olds | |||||
| Stimulus interference (SI:C) | 1.17 | .17 | 6.45 | <.001 | 1.03 |
| Response interference (SRI:SI) | 1.07 | .10 | 3.72 | .001 | .60 |
| 10-year-olds | |||||
| Stimulus interference (SI:C) | 1.06 | .05 | 7.00 | <.001 | 1.18 |
| Response interference (SRI:SI) | 1.08 | .14 | 3.39 | .002 | .57 |
| Adults | |||||
| Stimulus interference (SI:C) | 1.02 | .05 | 1.18 | .246 | .19 |
| Response interference (SRI:SI) | 1.07 | .06 | 7.51 | <.001 | 1.22 |