Table 1.
Summary of behavioral data for both subject groups
| Italian group | British group | |
| Mean (SD) | Mean (SD) | |
| Mill Hill age-matched percentilea | 60.7 (24.2) | 54.8 (27.9) |
| Mill Hill completion time (in min) | 15.1 (5.4) | 16.4 (6.7) |
| Self-rated proficiency in the second language | 75.8 (12.1) | 54.8 (21.3) |
| Unknown second language words on postscan test | 2.6% (3.3) | 10.9 (8.1) |
| Percent of errors for English regular words | 2.5% (3.9) | |
| Percent errors for English irregular words | 2.8% (4.4) |
a
The Mill Hill age-matched percentile is based on normative values in native English speakers. Although the British group knew fewer words in their second language, this potential confound for a between group comparison is not relevant to the results reported in this paper which focuses on within group variance that is common to both groups.