Most adults, especially women, hold infants and objects representing infants, such as dolls, preferentially on the left side. The attention hypothesis credits the effect to left-directed attention for perception of emotionally salient targets, faces being prime examples. Support comes from studies showing stronger left visual hemispace (LVH) biases in left-holders than right-holders on the Chimeric Faces Test (CFT), but control tests with non-social/emotional objects are needed. We therefore observed young women holding a doll, a book, and a bag, and compared their scores with their performance on the CFT. We also assessed their handedness to check on its possible role. Overall, only the doll elicited a significant side bias, with 57% of all holds on the left, 2% in the middle, and 41% on the right. On the CFT, only left-holders had an LVH bias, whereas right-holders had no bias in either direction. Only the doll-hold scores were consistently related to CFT scores, and for none of the objects was handedness related to side-of-hold.

Most women hold infants on their left side. They do the same when depicted in works of art. Does the latter accurately reflect the real-life bias, the artist's own aesthetic preference, or something else, such as the artist's handedness, sex, direction of attentional bias, or even the artist's own side-preference for holding infants? As a first step to finding out, we showed 272 young adults (85 men, 187 women) 20 pairs of paintings of the Madonna and Child, the original on one side, its mirror-reversal on the other, and asked which one they preferred. Along with assessing the effects of the variables already mentioned, we used equal numbers of paintings originally depicting left-holds and right-holds to control for the possible effects of differences between the paintings other than side-of-hold itself, such as in their colour scheme, background details, and the type of hold shown (e.g., cradle vs seated on lap). Each pair was presented twice, once with the original on the left, once on the right, for a total of 40 trials. Women and men alike more often preferred left-hold images, but the difference was significant only for women. Preferences were also stronger for original left-hold paintings than for the mirror-reversals of original right-hold paintings, suggesting that the originals differed in ways affecting preference beyond those we tried to control. Overall preference for left-hold images was enhanced when the images were on the viewer's left. As for the other variables, they were for the most part unrelated to preferences. The reasons for the preference thus remain unclear but it is evidently affected by multiple variables, with at least some clearly different from those affecting side-of-hold preferences of real mothers holding real infants.

Photographic and direct-observation studies show that most adults hold infants on the left side. This basic directional effect is well established, but other details are still uncorroborated, uncertain, or inconsistent across studies. These include the overall strength of the bias, the role of the sex, parental status, and experience of the holder, and the sex and age of the infant. Given their importance for understanding the bias, we sought further information from a large sample of photographs of mothers and fathers, some of them first-time parents, others not, holding their infants in the first minutes, hours, or days after birth. The results confirmed the basic directional effect and provided information on the other variables. They also raise questions for further research, especially as it pertains to the use of photographs vs direct observation.