Materials and stimuli
Apparatus. E-prime version 2.0.10.242 software (Psychology
Software Tools, Pittsburgh, PA) was used. The computer model was Dell
Inspiron 22- 3264 with Window 10 operation system installed. The display
resolution of screen was 1024 × 768. Emotional facial stimuli are
presented at a distance of approximate 45 cm with a resolution of 210 ×
240 for each emotional face.
Cognitive load. The distraction involved mathematical equations
with addition and subtraction as cognitive load. There were 36 trials of
mathematical equations in each level of distraction, 108 trials in
total. The varying levels of complexity of mathematical equations
implicated that the amount of cognitive load was actively maintained in
WM. Three levels of distraction were resulted: control, low, and high.
Cognitive load was operationalized as a function of distraction in which
a given event captures WM resources thus hindering other central
activities. The low level of distraction indicated lower cognitive load;
the high level of distraction indicated higher cognitive load.
To experimentally varied the three levels of distraction, the operand in
each equation increased (e.g., 1+9=8 or 9-7=6 in the control level;
19+1=20 in the low level; 10+2-1=5 in the high level). The processing
component was performed progressively, namely the control level of
distraction was performed firstly, and then the low level following the
high level.
As the relatively increasing complexity of mathematical equations in the
subsequent levels, their average time used in the processing component
in the control level (plus 3 SD ) was then used for the subsequent
processing component for the corresponding individual.
The emotional faces. All emotional facial stimuli were obtained
from Yale face database (Georghiades, 1997). Facial stimuli of 15
individuals included positive, negative, and neutral faces. All facial
stimuli are grey-scaled images. Originally, participants were required
to solve mathematical equations while remembering letters in Aospan.
Major modification that changed to-be-remember letters to naturally
emotional faces was made to Aospan. A block design was used, with each
block contained 36 trials of mathematical equations and 36 trials of
emotional faces. Each level of distraction consisted of 3 blocks for
each type of emotional faces. Except for the control level, it contained
4 blocks with one of those blocks used for 36 mathematical equations to
calculate the time limit for differences in individual ability. The
accuracy criterion was 85% which prevented participants from answering
these by chance. Three of the remaining blocks in the control level
comprised 12 trials of each type of emotional faces.