I like it by mere association: Conditioning preferences in infants.

Preferences have a profound impact on our behavior; however, relatively little is known about how preference formation works early in life. Evaluative conditioning occurs when the valence of an initially neutral object changes when it is paired with a positively or negatively valenced stimulus. It is possible that evaluative conditioning may account for early preference learning; however, the extent to which this kind of learning operates during infancy has not been empirically tested. The aim of the current studies was to assess whether infants' preferences for neutral objects is influenced by pairing them with affective stimuli (Experiment 1: happy vs. angry faces, N=20; Experiment 2: mother vs. stranger faces, N=22). Infants' preferences were tested using both looking time and behavioral choice measures. The results showed that infants tended to choose the object that had been paired with the positive stimulus (Experiment 1: 13/20; Experiment 2: 14/22). Gaze behavior at test did not differentiate between the two objects; however, gaze behavior during conditioning predicted infants' behavioral preference. Only infants who looked longer at the affective stimulus than at the object during learning chose the object that had been paired with positive valence more often than chance. These results suggest that infants' preferences may be influenced by learned associations between objects and affective stimuli, a process akin to evaluative conditioning in adults.