2.2 Materials
To investigate the cross-task adaptation effect of bilingual language control on executive control in forced, voluntary, and natural switching contexts, we adopted a cross-task paradigm in which flanker trials were intermixed with picture-naming trials. To ensure that the switching contexts mirrored the bilingual experience in real-life switching situations as accurately as possible, we administered a survey to 35 participants from same population, but who were not involved in the formal experiment. The survey presented pictures and their Chinese and English names at the same time in two parts. In the first part, participants were instructed to choose in which language the pictures were most commonly used in daily life, and to report the frequency of such use. Language-biased items were selected for the experiment if more than 80% of respondents could name them in one language, or if the average rating for its use exceeded 80% (Zhu et al., 2022). In the second part, participants were instructed to rate the familiarity of the target Chinese words and their English translation equivalents. Words that were judged equally familiar in their two languages were chosen for the experiment.
The picture stimuli included 36 black-and-white line drawings (Snodgrass & Vanderwart, 1980; standardized by Zhang & Yang, 2003), of which 24 were used in the formal experiment and 12 were used in a practice block. In the natural switching block, there were eight picture stimuli with strong language-biased names. Specifically, four of them were strongly biased towards English, meaning it was difficult to use a Chinese word to name the stimulus (e.g., Windows , an operating system), and four were strongly biased towards Chinese (e.g., zongzi , a traditional food in China), meaning it was difficult to use an English word to name of the stimulus. In the forced switching block, 4 words with the same familiarity of L1 names and L2 equivalents were used as target stimuli. In the voluntary switching block, another 4 words with the same familiarity of L1 and L2 names were used as target stimuli.
Flanker stimuli comprised a display of five horizontal arrows, wherein the central arrow either matched or did not match the direction of the flanking arrows. This arrangement provided four distinct types of stimuli: 1) all arrows pointing left, 2) all arrows pointing right, 3) all arrows pointing left except for the center arrow, and 4) all arrows pointing right except for the center arrow.