Mothers’ and fathers’ lateral biases for holding their newborn infants: A study of images from the World Wide Web

Abstract

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.

We wish to thank Michael Corballis, Stanley Coren, and an anonymous reviewer for their helpful comments and suggestions about the manuscript.

Notes

¹For mothers, these impressions are compatible with figures from hospital surveys in the United States for the years 1998–2000. For vaginal deliveries, 35.6% of mothers were 18–24 years old, 51.7% were 25–34, and 12.7% were 35 and older. For primary and repeat C-section deliveries, which comprised 23.2% of all deliveries in 2000, the percentages changed mostly in the form of increases in the oldest group from 17.4% to 24.1% (Jiang et al., 2000, p. 13, and Figures 15 and 19; Korst & Platt, 2001; Martin, Hamilton, Ventura, Menacker, & Park, 2002).

²In the United States, shorter obstetric stays are a recent development dictated primarily by rising medical and insurance costs (e.g., Eaton, 2001; Galbraith, Egerter, Marchi, Chavez, & Braveman, 2003; Young, 1996). By contrast, in de Château's studies (1983), conducted in Sweden in the 1970s when the average stay was longer, all observations were made on the fourth day.

³What makes such reversals even more unlikely is that they would normally occur at some stage of the production process. Today, with the advent of digital cameras which have largely replaced conventional film cameras, there is no “production process” to speak of—that is, there is no negative and thus no opportunity to print a positive in reverse orientation.