Roles of familiarity and novelty in visual preference judgments are segregated across object categories

Abstract

Understanding preference decision making is a challenging problem because the underlying process is often implicit and dependent on context, including past experience. There is evidence for both familiarity and novelty as critical factors for preference in adults and infants. To resolve this puzzling contradiction, we examined the cumulative effects of visual exposure in different object categories, including faces, natural scenes, and geometric figures, in a two-alternative preference task. The results show a clear segregation of preference across object categories, with familiarity preference dominant in faces and novelty preference dominant in natural scenes. No strong bias was observed in geometric figures. The effects were replicated even when images were converted to line drawings, inverted, or presented only briefly, and also when spatial frequency and contour distribution were controlled. The effects of exposure were reset by a blank of 1 wk or 3 wk. Thus, the category-specific segregation of familiarity and novelty preferences is based on quick visual categorization and cannot be caused by the difference in low-level visual features between object categories. Instead, it could be due either to different biological significances/attractiveness criteria across these categories, or to some other factors, such as differences in within-category variance and adaptive tuning of the perceptual system.

Fig. 1.

Preference judgment experiment. (A) Stimuli and procedure. A trial consisted of the three steps: (i) initial fixation of 1 s, (ii) free visual inspection until decision, and (iii) reporting of relative preference on a 7-point scale using a mouse. The next trial was essentially the same, except that one of the faces was presented again at a random position (left or right) and paired with a new face. Thus, the same stimulus was presented in all of the 26 trials, but paired with a new stimulus in each trial. (B) Time course of subject preference ratings through a block, averaged for each object category (n = 11). The mean value of the 7-point rating is plotted against trial number. The top of the abscissa indicates a stronger preference for familiarity, whereas the bottom indicates a stronger preference for novelty. Orange represents faces; green, natural scenes; maroon, geometric figures. Error bars represent ± SEM.

Fig. 2.

Line drawing experiment. (A) Original and line drawing version of face and natural scene image samples. (B) Results of preference judgment with line drawings (n = 10). Relative preference is plotted against serial trial numbers in each category, as in Fig. 1B. Orange represents faces; light green, natural scenes including all 8 subcategories; green, natural scenes without “lake” subcategory, which subjects found most difficult to recognize. Error bars represent ± SEM.

Fig. 3.

Results with upside-down stimuli (n = 11). Relative preference is plotted against serial trial numbers. Red denotes upside-down faces; light green, upside-down natural scenes. For comparison, the results with upright stimuli (orange, faces; green, natural scenes) are replotted from Fig. 1B. The dark-red curve for faces and the dark-green curve for natural scenes represent the data pooled from several different experiments (n = 42), all with upright stimuli and procedures that were identical up to the 15th trial. Error bars represent ± SEM.

Fig. 4.

Results of preference judgment with a 3-wk blank (n = 11). Relative preference is plotted against serial trial numbers. Orange represents faces; green, natural scenes; maroon, geometric figures. The absence of lines connecting the 15th and the 16th trials indicates that there was a 3-wk blank between the two trials. Error bars represent ± 1 SEM. The blank seemed to be sufficient to cancel out the memory effects in all of the categories, and the same cumulative effects were duplicated over trials after the blank.