Table 3.
Global and local switch costs in terms of accuracy (in %) for each participant group and for each discrimination task.
| Groups | Global SC | Local SC | ANOVA | Contrast Tests | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| M | SE | 99% CI | M | SE | 99% CI | Effect | F ratio | df | Partial ƞ2 | GC | Global SC | Local SC | |
| Letter Discrimination Task | |||||||||||||
| College Students | 4 | 1 | [3,5] | 0 | 0 | [0,1] | G | 206.12** | 1 | 0.65 | 1 | t(84.1) = −1.8 | t(84.0) = 4.2** |
| 61–74 year olds | 3 | 1 | [0,3] | 2 | 1 | [0,3] | T | 17.00** | 1 | 0.14 | 2 | t(25.4) = −0.7 | t(35.3) = 3.1** |
| 75–89 year olds | 3 | 1 | [1,5] | 2 | 1 | [0,3] | C | 46.93** | 1 | 0.30 | 3 | t(25.9) = 0.1 | t(36.3) = 0.1 |
| Brightness Discrimination Task | |||||||||||||
| College Students | 3 | 1 | [0,4] | 2 | 1 | [3,5] | G × T | 3.84* | 2 | 0.07 | 1 | t(61.2) = 2.5** | t(66.7) = 0.4 |
| 61–74 year olds | 5 | 1 | [3,7] | 2 | 1 | [0,4] | G × C | 1.18 | 2 | 0.02 | 2 | t(27.4) = 3.5** | t(40.0) = −0.3 |
| 75–89 year olds | 8 | 1 | [5,10] | 1 | 1 | [0,3] | C × T | 1.61 | 1 | 0.02 | 3 | t(39.2) = 1.5 | t(53.7) = −0.7 |
| G × C × T | 11.74** | 2 | 0.18 | ||||||||||
Note. SC = Switch Costs; Global SC = performance difference between pure and no-switch trials. Local SC = performance difference between no-switch and switch trials; ANOVA = analysis of variance; G = group; T = task type; C = switch cost type; CI = confidence interval; GC = group comparisons (1 = college students vs. 61–74 year olds; 2 = college students vs. 75–89 year olds; 3 = 61–74 year olds vs. 75–89 year olds).
*
p < .05;
**
p < .01.