This activity described a research study by ahmed m. megreya and a. mike burton (2008) that showed participants an unfamiliar face and asked them to match it with a new photo of the same person in a set of photos of another ten unfamiliar faces. based on their results, they concluded that:

"six months ago, several of molly's friends joined the trimtime fitness center. each of them participated in trimtime's weight-reduction and fitness regimen. all reported substantial weight reduction, and all are visibly slimmer. molly is convinced. she joins trimtime and enrolls in the program, hoping and expecting to see the same results. she is especially delighted to learn that trimtime had adjusted its program to make it even more effective in a shorter period of time." what is the feature in question/attribute of interest in this argument?