FOOD STIMULI AND GENDER

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5.2 Methodological Considerations
5.2.1 Stimuli and Areas of Interest
Using validated pictures from databases makes research more comparable and the
stimuli and setup more transparent. The complexity of the images was analyzed together
with other data that could affect salience. These variables were statistically analyzed to avoid
significant differences between the food groups. Previous studies using visual food stimuli
have also taken into account variables such as complexity and brightness (Frank et al., 2010;
Meule & Kübler, 2014).
Even though the images were carefully chosen, the size of the images was not
established. The images were chosen from validated databases and subjectively appeared to
be the same size. For most images, the distance between stimuli was sufficient, and the
randomization and placing of the AOIs functioned as expected. Nevertheless, one food
stimulus, pizza, was much larger than all other stimuli, giving rise to an AOI overlap. For
this reason, pizza had to be excluded in some trials.

5.2.2 Presentation Software
A staff with programming experience is recommended for eye-tracking studies
(Holmqvist et al., 2011). However, the present software development and user-friendly
interfaces for presentation and statistical analysis make it possible to run an experiment
without a computer programmer. PsychoPy software is positively rated as being suitable for
cognitive research and having high levels of accuracy and precision (Garaizar et al., 2014).
The timing of the software was accurate in the experiment. However, some stimuli
changes did not overlap precisely. Some frames from the last slide were present as the
stimuli changed. This issue meant that changes between stimuli were not as precise as