We averaged preferences across participants, to calculate a preference coefficient for each stick figure or quadrilateral shape, and used linear regression to relate our participants' preference of each figure or shape to the year of the production from which each original image was selected.
The fraction of time spent on each surface by single larvae was used to calculate a preference index score (Preference Index = (time on test substrate time on control substrate)/total time).
After 1, 3 and 5 min we determined the number of larvae on either the odour side or the blank side or the middle stripe, allowing us to calculate a preference score as: (3)This experiment was performed either as described, or in the presence of the buzz.
Furthermore, with regard to the economic evaluation, SF-12D is used to calculate a preference-based utility index, SF-6D.
The SF-6D classification is a method to calculate a preference-based single index for health using general population values, which varies (conceptually) from 0 to 1 with higher scores indicating a better health state [ 27].
The computer then calculated a novelty preference, the percentage of the total test time that the infant spent looking at the novel stimulus.
To calculate a scrounging preference, all scrounging actions were divided by the total number of actions at the box.
We record the number of larvae on either side of the dish and calculate a gustatory preference index (PREFGustatory) as (1) In this equation, # indicates the number of larvae on the respective half of the dish.
For both groups, we then calculate an odor preference ranging from −1 to 1.
We calculate an odor preference ranging from −1 to 1 by determining the number of animals observed on the one side minus the number of animals observed on the other side, divided by the total number of larvae.
