Procedure.
The participants were individually tested in the computer laboratory and
informed consent was obtained from all individual participants included
in the study. First, they were instructed to enter their information
into the start-up information of E-prime, including their age and sex.
Then, they were instructed to perform the computerized experiment – the
modified Aospan. They were required to complete the practice trials
before each condition of the distracting task, and then complete the
real trials.
Each practice session contained 3 trials presented in math-emotional
face strings. The presentation of processing component (distraction) and
storage component (serial recall of emotional faces) in the control
level was serial, the practice session in the control condition required
them to solve 3 trials of mathematical equations and then 3 trials of
emotional faces with a set size of 3 for recalling in the same presented
order. In both the practice and real trial, all the emotional faces were
presented on the screen for 800 ms. At the recall, the participant saw a
3 × 2 matrix of emotional faces.
In the control level, they first solved 36 real trials of mathematical
equations and then performed 12 real trials for each type of emotional
faces at the set size of 3. For each of the subsequent trials of the low
and high level of distraction, the mathematical equations were
paralleled with the emotional faces. In the low level, the participants
performed 3 strings; thus, the set size for recalling the emotional
faces was 3. In the high level, they performed 6 strings in which the
set size for recalling the emotional faces was doubled to 6 as to
increase the difficulty. The sequence of the levels of distraction was
in fixed order. The order for types of emotional faces was
counterbalance between participants and emotional faces for recalling
were pseudorandomized. All procedures performed in studies involving
human participants were in accordance with the ethical standards of the
institutional and/or national research committee and with the 1964
Helsinki declaration and its later amendments or comparable ethical
standards.