Figure 1
Exemplary Illustration of Accumulation of SOA increments Used in Specific Session (S1, S2, S3) to switch SOA.
Note: n = first trial in block. After the response to the number task, the waiting time for the number in the first repetition trial (n + 1) is equivalent to the SOA increment. In subsequent trials waiting time prolongs according to the specific SOA increment. The observed waiting time in the switch trial (n + 3) is recorded as the switch SOA. In the trial after the task switch (n + 4) the waiting time starts anew.
Figure 2
Typical Trial Structure in the Free-Choice Blocks.
Note: Waiting time for repetition stimulus is equivalent to the number of task repetitions × specific SOA increment (20 ms, 40 ms or 60 ms). SOA increments varied between the sessions, ITI duration varied blockwise.
Table 1
Mean Median Switch Costs, Switch Rates, Mean Median Switch SOA, Separately for Each ITI/SOA increment Combination.
| ITI 0 MS | ITI 250 MS | ITI 700 MS | |||||||
|---|---|---|---|---|---|---|---|---|---|
| SOA +20 MS | SOA +40 MS | SOA +60 MS | SOA +20 MS | SOA +40 MS | SOA +60 MS | SOA +20 MS | SOA +40 MS | SOA +60 MS | |
| Switch costs (ms) | 154 (137) | 141 (111) | 158 (104) | 78 (90) | 75 (90) | 68 (82) | 38 (67) | 38 (60) | 55 (112) |
| Switch rate (%) | 25 (22) | 30 (23) | 31 (19) | 30 (22) | 38 (22) | 44 (24) | 38 (23) | 43 (23) | 49 (23) |
| Switch SOA (ms) | 114 (85) | 182 (135) | 235 (147) | 88 (75) | 126 (106) | 163 (120) | 63 (46) | 108 (85) | 141 (113) |
| N | 82 | 91 | 93 | 83 | 87 | 93 | 86 | 89 | 90 |
[i] Note: Switch costs = task switch RT – task repetition RT, Standard errors of the means in parentheses. N = remaining sample size in each condition after participants exclusion procedure.
Figure 3
Relationship between Task Performance and Task Selection in each ITI/SOA increment Combination.
Note: Panel A displays scatterplots of individual median switch costs against individual switch rates. Panel B displays scatterplots of individual median switch costs against the individual median SOAs of switch trials. Dashed lines represent the corresponding regression lines.
Table 2
Differences Between Switch Costs and Switch SOA (Diff Score) Separately for the Specific ITI/SOA increment Combinations.
| ITI 0 MS | ITI 250 MS | ITI 700 MS | |||||||
|---|---|---|---|---|---|---|---|---|---|
| SOA +20 MS | SOA +40 MS | SOA +60 MS | SOA +20 MS | SOA +40 MS | SOA –60 MS | SOA +20 MS | SOA –40 MS | SOA +60 MS | |
| mean Diff Score | –39.78 | 39.84 | 76.76 | 10.10 | 50.20 | 94.19 | 24.78 | 70.30 | 86.74 |
| t | –3.09* | 3.53** | 6.25** | 1.04 n.s. | 4.28** | 8.57** | 3.69** | 7.83** | 5.64** |
| (dft) | (81) | (90) | (92) | (82) | (86) | (92) | (85) | (88) | (89) |
| BF01 | 1/10 | <1/30 | <1.100 | 4.93 | <1100 | <1/100 | <1.30 | <1/100 | <1/100 |
[i] Note: * p ≤ .05, ** p < .001. BF01 = the Bayes Factor in favor of the “null” Hypothesis, quantifies the evidence for the absences of the difference.
Figure 4
Means of Diff Score (median switch SOA – median RT switch cost) as a Function of ITI, and SOA increment.
Note: Error bars represent a 95 % confidence interval for the mean.
Figure 5
Relationship between individual trade-off ability (absolute value of Diff Score) and switch rate.