Which aspect of friends’ preferences was highlighted in Zajonc's study regarding mirror-image preferences?

The correct choice highlights that friends tend to choose real pictures over mirror images. Zajonc's research into mirror-image preferences illustrates the mere exposure effect, where individuals develop a preference for stimuli simply because they are familiar with them. This preference extends to friends, who are likely to share similar experiences and exposures, leading them to favor the same types of images.

In this context, individuals often prefer the representations of themselves that they see most frequently – which, for most people, are mirror images due to the way they see themselves in reflections. However, friends, who know each other well and may have shared numerous experiences, are more inclined to favor the real images of each other rather than the mirror reflections. This indicates how social connections and shared experiences can influence personal preferences, particularly in the realm of self-representation.