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This study examined developmental changes in children's abilities to make trustworthiness judgments based on faces and the relationship between a child's perception of trustworthiness and facial attractiveness. One hundred and one 8-, 10-, and 12-year-olds, along with 37 undergraduates, were asked to judge the trustworthiness of 200 faces. Next, they issued facial attractiveness judgments. The results indicated that children made consistent trustworthiness and attractiveness judgments based on facial appearance, but with-adult and within-age agreement levels of facial judgments increased with age. Additionally, the agreement levels of judgments made by girls were higher than those by boys. Furthermore, the relationship between trustworthiness and attractiveness judgments increased with age, and the relationship between two judgments made by girls was closer than those by boys. These findings suggest that face-based trait judgment ability develops throughout childhood and that, like adults, children may use facial attractiveness as a heuristic cue that signals a stranger's trustworthiness.

Existing research suggests that adults make effective trustworthiness judgments based on facial attractiveness during initial interactions. However, little is known about how children judge trustworthiness from faces. The present study examined the facial features that contributed to judgments of trustworthiness and attractiveness by three groups of Chinese children aged 8 years old (n=34; 17 boys), 10 years old (n=34; 17 boys), and 12 years old (n = 34; 17 boys) and a comparison group of 37 undergraduates (M age=20.2 yr.; 16 men). Using FaceGen Modeler 3.1, a total of 400 East Asian adult faces (200 male, 200 female) portraying neutral emotions with direct gazes were generated. The faces were represented by 61 shape features and were presented for a maximum of 3,000 msec. in the center of the computer screen in randomized order. The participants were asked to judge whether each person was trustworthy and to rate the level of trustworthiness; 1 month later, the attractiveness of the same faces was judged using a similar procedure. The children and the adults used similar facial features to judge trustworthiness (e.g., the brow ridge, nose, and chin). Some of the facial features used by the different age groups as the basis for the trustworthiness and attractiveness judgments were similar. Facial attractiveness accounted for roughly 30 to 60% of the variance in the groups' trustworthiness judgments. Thus, facial attractiveness may serve as a heuristic property that signals trustworthiness and guides adaptive social decisions. More importantly, even children as young as 8 years old use a strategy similar to that of adults to make trustworthiness judgments, although some differences in the use of specific facial features were observed among the age groups.

This paper proposes a new reversible data hiding scheme for encrypted images by using homomorphic and probabilistic properties of Paillier cryptosystem. The proposed method can embed additional data directly into encrypted image without any preprocessing operations on original image. By selecting two pixels as a group for encryption, data hider can retrieve the absolute differences of groups of two pixels by employing a modular multiplicative inverse method. Additional data can be embedded into encrypted image by shifting histogram of the absolute differences by using the homomorphic property in encrypted domain. On the receiver side, legal user can extract the marked histogram in encrypted domain in the same way as data hiding procedure. Then, the hidden data can be extracted from the marked histogram and the encrypted version of original image can be restored by using inverse histogram shifting operations. Besides, the marked absolute differences can be computed after decryption for extraction of additional data and restoration of original image. Compared with previous state-of-the-art works, the proposed scheme can effectively avoid preprocessing operations before encryption and can efficiently embed and extract data in encrypted domain. The experiments on the standard image files also certify the effectiveness of the proposed scheme.