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Pink and blue: The color of gender

  • Fondazione Policlinico Universitario A. Gemelli IRCCS - Rome (Italy)
Pink and blue: the color of gender
Paolo Frassanito & Benedetta Pettorini
Published online: 4 January 2008
Springer-Verlag 2007
Assigning color to gender is mostly a twentieth-century
trait. It should be noted that it is a practice limited most
often to Western Europe and the Americas. It would also
seem that the effect of color-coded gender differences (pink
for girls, blue for boys) existed oppositely initially [10].
In fact, this reversal of what we consider normal was
considered conventional, even in the early twentieth
century. The debate of when and why pink and blue came
into fashion to designate gender rages on, but alm ost every
argument alludes to a passage in the novel Little Women,
published in 1868: Amy ties a pink bow and a blue bow
on Megs twins Daisy and Demi, so people will know the
difference between the girl and the boy. This is said to be
done in the French style, suggesting that it might have
been possible in France that pink and blue were already
However, there is evidence that this practice was not
always common or always don e throughout much of
Europe. In fact, in the nineteenth century, parents dressed
infants in white dresses, suggesting that color and dresses
were not used to distinguish between girls and boys [3].
At one point, pink was considered more of a boys color,
as a watered-down, bold, dramatic red, which is a fierce
color. Instead, blue was considered more for girls. Probably
this choice was affected by the fact that blue, especially
dark blue, was associated with the Virgin Mary in Christian
Europe. In fact, painters often mixed lapis lazuli into paints
to depict what was considered the most sacred feminine
The Sunday Sentinal, an American newspaper, in 1914
advised mothers: If you like the color note on the little
ones garments, use pink for the boy and blue for the girl, if
you are a follower of convention (March 29, 1914).
Similarly, Ladies Home Journal informed: There has been
a great diversity of opinion on the subject, but the generally
accepted rule is pink for the boy and blue for the girl. The
reason is that pink being a more decided and stronger color
is more suitable for the boy, while blue, which is more
delicate and dainty, is prettier for the girl (June, 1918).
The current pink for girls and blue for boys was not
uniform until the 1950s [11]. It would seem that Nazi
Germany had something to do with the association of pink
with femininity: catholic traditions in Germany and
neighboring countries reverse the current color coding,
because of the strong association of blue with the Virgin
Mary; the Nazis in their concentration camps use a pink
triangle to identify homosexuals. The Nazis choice of pink
suggests that, by the 1930s, it was a color that in Germany
had become associate with girls.
Thus, Dress Maker Magazine stated: The preferred
color to dress young boys in was pink! Blue was reserved
for girls as it was considered the paler, more dainty of the
two colors, and pink was thought to be the stronger (akin to
red). It was not until W WII that the colors were reversed
and pink was used for girls and blue for boys...
After World War II, blue was used extensively for mens
uniforms. Therefore, blue became associated as more of a
masculine color. From the 1940s onward, pink was pushed
as a womans color. Think pink
was the marketing slogan
to convince women to embrace their femininity.
The 1950s featured a virtual color explosion, not only in
clothing, but also in things like appli ances and furniture.
Dressing children in pink and blue to specifically denote
gender suggested the rising middle class and above. In
Childs Nerv Syst (2008) 24:881882
DOI 10.1007/s00381-007-0559-3
P. Frassanito (*)
B. Pettorini
Pediatric Neurosurgery, Catholic University,
Largo A. Gemelli, 8,
00168 Rome, Italy
other words, people who could afford to make the gender
assignment did so, since many infants appear somewhat
asexual when first born.
Another possible theory links pink and blue gender
references to the 1950s film Funny Face, which stars
Audrey Hepburn. Hepburn was thought an extremely
feminine woman, and her outfits in pink may have proven
inspiring. This explanation is somewhat unlikely, given that
the film was not released until 1957.
Thus, the pink and blue tradition is recent and relatively
exclusive to the Western world, but the girls preference for
the color pink seems to have deeper roots. In a recent study,
the researchers report a preference for blue color on a
yellowblue scale both in males and in females, but a girls
preference for red on a greenred scale. This sex difference,
revealed by a rapid paired-comparison task, is robust and
cross-cultural [8]: could it have a biological basis or is it
only social imprinted ?
A re cent argumen t proposes a bi ological ba sis,
connected to evolved sex differences in specialized visual
pathways that allows females to better discriminate red
wavelengths. The huntergatherer theory propos es that
female brains should be specialized for gather ing-related
tasks and is supported by studies of visual abilities [13].
Tricromacy and the second redgreen system (L M
opponent channel) are modern adaptations in primate
evolution though t to have evolved to facilitate the identi-
fication of ripe, yellow fruit or edible red leaves embedded
in green foliage [12]. It is therefore plausible that, in
specializing for gathering, the female brain honed the
trichromatic adaptations (and developed more the P-cell
pathway of vision), and these underpin the female prefer-
ence for objects reddish. Research on foraging in contem-
porary nonhuman primates [5] supports this hypothesis.
Whereas discrimination of red wavelengths appears to
facilitate identification of plant food, a preference for red
or pink appears to have an advantage for successful female
reproduction. This preference for reddish-pink is thought to
exist because infant faces compared to adult ones are
reddish-pink, and red or p ink may signal approac h
behaviors that enhance infant survival [7].
Similarly, evolutionary theorists have reasoned that selec-
tion pressures might have contributed to spatial abilities in
men that enhanced the hunt and capture of animals, such as
the identification of spatial position, object movement, and a
global analysis of visual scenes [6], that are processed by the
M-cell pathway, phylogenetically older [1]. Other findings in
studies on primates are consistent with androgen-dependent
effects on visual processing pathway structure at the level of
the cortex, supporting a biological basis of the preference for
the color [2].
On the other hand, the segregation of the anatomical and
functional proper ties of the M-cell and P-cell pathways at
the cortical level is less pronounced in infants, if compared
to adults [4], consistent with the proposal that parcellation
and specializa tion of the visual processing stre am is
directed by experience in postnatal life and so enhancing
the socia l a nd cultural influences in addition t o the
biological basis [9].
1. Alexander GM (2003) An evolutionary perspective on sex-typed toy
preferences: pink, blue and the brain. Arch Sex Behav 32:714
2. Bachevalier J, Hagger C (1991) Sex differences in the develop-
ment of learning abilities in primates. Psychoneuroendocrinology
3. Chiu SW, Gervan S, Fairbrother C et al (2006) Sex-dimorphic
color preference in children with gender identity disorder: a
comparison in clinical and community controls. Sex Roles
4. Dobkins KR, Anderson CM (2002) Color-based motion process-
ing is stronger in infants than in adults. Psychol Sci 13:7680
5. Dominy NJ, Lucas PW (2001) Ecological importance of trichro-
matic vision to primates. Nature 410:363366
6. Eals M, Silverman I (1994) The huntergatherer theory of spatial
sex differences: proximate factors mediating the female advantage
in location memory. Ethol Sociobiol 15:95105
7. Highley JD, Hopkins WD, Hirsch RM et al (1987) Preferences of
female rhesus monkeys (macaca mulatta) for infantile coloration.
Dev Psychobiol 20:718
8. Hurlbert AC, Ling Y (2007) Biological compnents of sex
differences in color preference. Curr Biol 17(16):623625
9. Johnson MH (2001) The development and neural basis of face
recognition: comment and speculation. Infant Child Dev 10:3133
10. Paoletti JB (1997) The gendering of infants and toddlers
clothing in America. In: Martine KA, Ames KL (eds) The
material culture of gender, the gender of material culture.
University Press of New England, Hanover, NH
11. Paoletti JB, Kregloh C (1989) The childrens department. In:
Kidwell CB, Steele V (eds) Men and women: dressing the part.
Smithsonian Institution Press, Washington, DC
12. Regan BC, Julliot C, Simmen B et al (2001) Fruits, foliage, and
the evolution of primate color vision. Philos Trans R Soc Lond B
Biol Sci 356:229283
13. Silverman I, Eals M (1992) Sex differences in spatial abilities:
evolutionary theory and data. Oxford Press, New York
882 Childs Nerv Syst (2008) 24:881882
... Since the 1980 s, research in social semiotics has highlighted that colour is attributed with social values in different societies at different times (Eco, 1985;Frassanito and Pettorini, 2008;van Leeuwen, 2011). For example, in western cultures, blue and pink are often related to gender. ...
... For example, in western cultures, blue and pink are often related to gender. According to Frassanito and Pettorini (2008), in Europe, before World War Two, blue was considered a more feminine colour while pink was considered a more masculine colour. However, after the war, the social meaning associated with the colour blue changed -it no longer connoted feminine qualities but came to be associated with masculinity partly because most men's uniforms, especially the ones in Germany, were in blue. ...
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... Specifically, in Western culture, girls are often dressed in pink, while boys are often dressed in blue (Pomerleau et al., 1990). These gender-color associations have emerged in the Western world since the 1950s (Frassanito and Pettorini, 2008;Ben-Zeev and Dennehy, 2014;Grisard, 2018), and such color preference differences between the two genders may extend from childhood to adulthood (e.g., Cunningham and Macrae, 2011). Nevertheless, a recent study demonstrated, at least in some Western societies, that pink is a color restricted to female gender (i.e., only girls prefer pink), whereas blue is a neutral color that is commonly favored by both genders; such female gender preference toward pink was found in children as young as 10 years old (Jonauskaite et al., 2019). ...
... In addition, majority of those studies (except for Wang et al., 2017) were conducted in Western societies, and little is known about whether similar gendercolor association exists in contemporary Chinese society. Frassanito and Pettorini (2008) have pointed out that genderdefined application of pink and blue is relatively exclusive to Western culture. Moreover, many studies suggest that there is no conclusive knowledge about the fixed gendercolor preferences across different cultures (Jadva et al., 2010;Paoletti, 2012;Wong and Hines, 2015;Zhan and Dan, 2015;Jonauskaite et al., 2019).Therefore, it is worthy to explore how pink and blue are gender-symbolically represented by Chinese people. ...
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... Hence, a broader participant demography could qualify the clothing colour preferences reported here. Fashion preferences, including colour, change over time (Frassanito & Pettorini, 2008). It will therefore be important to test whether the associations of skin tone with clothing colour are durable or a passing fashion. ...
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... Also, Martin and Ruble (2004) noted that girls of school age are easily influenced by their counterparts in the use of colours. In other words, Empowering Students' Cognitive Learning using Computer Based Concept Maps 157 ______________________________________________________________________________ Frassanito and Pettorini (2008) explained that social construction has the historical backing of supporting the idea of colours by gender, especially blue for boys and pink for girls. In essence, Bimler, Kirkland, and Jameson (2004) argued that sex diversity in colour sensitivity has also been confirmed. ...
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... In Western societies, blue is stereotypically associated with boys and pink with girls [1][2][3]. Curiously enough, these gendered associations were initially arbitrary, but became pervasive in the early 20 th century [1,2,4]. Nowadays, many parents continue choosing pink when dressing their daughters, decorating their rooms [5], or buying them toys [6]. ...
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Courses: Gender roles and communication, interpersonal communication, communication theory. Objectives: This activity introduces students to the social construction of gender, and asks them to consider gender diversity by understanding that shades of pink and blue exist within the binary. Specifically, students are given blue or pink color palettes to think of masculinities or femininities that they think fit the gradient, and through the processing of assigning meaning to colors, students are able to learn that bodies are not only visually marked but also gendered. Students ultimately take away that gender is contested, negotiated, or affirmed in social interactions. In other words, gender is under construction—being built, developed, destroyed—and fluid.
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Primates are apparently unique amongst the mammals in possessing trichromatic colour vision. However, not all primates are trichromatic. Amongst the haplorhine (higher) primates, the catarrhines possess uniformly trichromatic colour vision, whereas most of the platyrrhine species exhibit polymorphic colour vision, with a variety of dichromatic and trichromatic phenotypes within the population. It has been suggested that trichromacy in primates and the reflectance functions of certain tropical fruits are aspects of a coevolved seed–dispersal system: primate colour vision has been shaped by the need to find coloured fruits amongst foliage, and the fruits themselves have evolved to be salient to primates and so secure dissemination of their seeds. We review the evidence for and against this hypothesis and we report an empirical test: we show that the spectral positioning of the cone pigments found in trichromatic South American primates is well matched to the task of detecting fruits against a background of leaves. We further report that particular trichromatic platyrrhine phenotypes may be better suited than others to foraging for particular fruits under particular conditions of illumination; and we discuss possible explanations for the maintenance of polymorphic colour vision amongst the platyrrhines.
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Trichromatic colour vision, characterized by three retinal photopigments tuned to peak wavelengths of approximately 430 nm, approximately 535 nm and approximately 562 nm (refs 1, 2), has evolved convergently in catarrhine primates and one genus of New World monkey, the howlers (genus Alouatta). This uniform capacity to discriminate red-green colours, which is not found in other mammals, has been proposed as advantageous for the long-range detection of either ripe fruits or young leaves (which frequently flush red in the tropics) against a background of mature foliage. Here we show that four trichromatic primate species in Kibale Forest, Uganda, eat leaves that are colour discriminated only by red-greenness, a colour axis correlated with high protein levels and low toughness. Despite their divergent digestive systems, these primates have no significant interspecific differences in leaf colour selection. In contrast, eaten fruits were generally discriminated from mature leaves on both red-green and yellow-blue channels and also by their luminance, with a significant difference between chimpanzees and monkeys in fruit colour choice. Our results implicate leaf consumption, a critical food resource when fruit is scarce, as having unique value in maintaining trichromacy in catarrhines.
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Large sex differences in children's toy preferences are attributed to gender group identification and social learning. The proposal outlined in this paper is that contemporary conceptual categories of "masculine" or "feminine" toys are also influenced by evolved perceptual categories of male-preferred and female-preferred objects. Research on children exposed prenatally to atypical levels of androgens and research on typically developing infants suggest sex-dimorphic preferences exist for object features, such as movement or color/form. The evolution and neurobiology of mammalian visual processing--and recent findings on sex-dimorphic toy preferences in nonhuman primates--suggest further that an innate bias for processing object movement or color/form may contribute to behaviors with differential adaptive significance for males and females. In this way, preferences for objects such as toys may indicate a biological preparedness for a "masculine" or "feminine" gender role-one that develops more fully as early perceptual preferences are coupled with object experiences imposed by contemporary gender socialization.
While developmental researchers have long noted that infants of many mammalian species, including primates, have characteristic physical features, such as a distinctive coat or skin color, and some authors have further suggested that these features serve to elicit caretaking and solicitous behavior, few systematic investigations of the actual salience of such features for adult conspecifics have been carried out to date. The present series of 3 studies sought to determine whether natal coat and/or facial skin coloration might provide desirable visual stimulation for rhesus monkey adult females. In these studies the faces and/or fur of 6-month-old rhesus monkeys were dyed to simulate the normal coloration of rhesus monkey neonates. Adult females varying in parity and rearing history were then tested for their relative preference between these infantile-colored 6-month-olds and both normally colored 6-month-olds and other differentially colored control stimulus monkeys. Results indicated that regardless of parity or rearing history the adult female subjects exhibited consistent preferences for the stimulus animals with neonatal-like reddish-pink facial skin coloration.
Based on their theory that sex differences in spatial abilities originated in human evolution as a function of division of labor, Silverman and Eals (1992) demonstrated in a series of studies that females consistently surpassed males in recall of locations of objects in a spatial array. The present studies were replications of the above, but with the inclusion of uncommon objects, for which subjects would not possess verbal labels. Female superiority for recall of locations of common objects as observed in Silverman and Eals was replicated across incidental and directed learning conditions. The female advantage occured as well for uncommon objects, but only under incidental learning conditions. Conjectures are offered regarding sex differences in attentional and imagery processes that could account for this pattern of results.
The role of steroid gonadal hormones in promoting sex differences in reproductive behaviors has been thoroughly studied in numerous mammalian species. More recent experiments have indicated that the presence or absence of steroid hormones during the critical period of brain differentiation likewise might promote the development of sex differences in cognitive abilities. Studies in infant rhesus monkeys have demonstrated that there exist sex differences in learning abilities that can be altered by perinatal hormonal manipulations, suggesting that testosterone might be a crucial factor responsible for the development of sex differences in cognitive styles. In addition, neonatal lesion studies have shown that the cortical areas mediating specific learning abilities mature at different rates in male and female infant monkeys. These findings support the view that the perinatal hormonal environment can affect the rate of brain maturation by influencing neuronal connectivity at the cortical level. The combined data from sex differences in learning abilities in human infants and their reversibility in endocrinological syndromes suggest that testosterone may affect the maturation of the human brain in a manner similar to that demonstrated in nonhuman primates.
One hallmark of vision in adults is the dichotomy between color and motion processing. Specifically, areas of the brain that encode an object's direction of motion are thought to receive little information about object color We investigated the development of this dichotomy by conducting psychophysical experiments with human subjects (2-, 3-, and 4-month-olds and adults), using a novel red-green stimulus that isolates color-based input to motion processing. When performance on this red-green motion stimulus was quantified with respect to performance on a luminance (yellow-black) standard, we found stronger color-based motion processing in infants than in adults. These results suggest that color input to motion areas is greater early in life, and that motion areas then specialize to the adultlike state by reweighting or selectively pruning their inputs over the course of development.