New study: Kids learning to dislike fat bodies by 2 and a half?

Photo by Petr Kratochvil. Licence: CC0 Public Domain

Title: Toddlers’ bias to look at average versus obese figures relates to maternal anti-fat prejudice

Authors: Ruffman, O’Brien, Taumoepeau, Latner, Hunter

Source: Journal of Experimental Child Psychology (2016) Vol 142, pp 195–202. Link to article

Super-quick summary: Toddlers below the age of three are already showing a preference for looking at average bodies rather than fat bodies. The effect is related to their mothers’ own anti-fat attitudes.

In more detail:

What they did

The authors tested 70 very young children and their mothers. The children could be separated into four groups by age: young infants (average 7 months), older infants (11 months), young toddlers (29 months), and older toddlers (32 months). There were a similar number of boys and girls in each group.

They sat the children on their mothers’ knees in front of two tv screen. First the screens both played a short child-friendly image, then after a beep, one screen showed a photo of an ‘obese’ person, and the other of an ‘average-weight’ person. A camera between the two screens captured where the childrens’ eyes went and how long they looked at each picture. The mothers were blindfolded during this part of the experiment so their responses to the images couldn’t bias where the children looked.

The pictures were before and after pictures from a television weight-loss show, and there were 10 pairs of pictures. They were of men and women in black short and white t-shirts, and the researchers covered the participants’ faces with a hat, so it was just the bodies on show. All the ‘before’ pictures had BMIs in the ‘obese’ range, with five being BMI 35-40, and five having BMIs over 40. The after pictures were a bit more variable because they depended on how much weight the contestants had lost during the show. Four of them had BMIs in the ‘normal weight’ range (BMI 18.5-24.9), 5 in the ‘overweight’ range (BMI 25-29.9), and 1 had a BMI just in the ‘obese’ range.

The researchers also collected information about the parents’ height and weight, the mothers’ education level, and the amount of TV the kids watched each day.

What they found

Well, let’s start with what they didn’t find: they ruled out a bunch of confounding factors – things that might impact on the results but that weren’t what the researches actually wanted to investigate. No difference between boys and girls. No difference according in looking at the ‘obese’ or ‘average’ images related to mother’s or father’s BMI, mother’s education, or normal TV viewing times. And no differences in looking times depending on whether the picture was of a man or a woman. So then they could move on to looking at the key factors of interest, kids’ ages and mothers’ anti-fat attitudes, to see whether those explained any differences in ‘obese’ vs ‘average’ looking times.

And yes, they did:

• Toddlers spent longer looking at both sets of images than did infants, no doubt due to their longer attention span.

• Older age and more negative anti-fat attitudes in the mother both predicted more time looking at the ‘average’ than the the ‘obese’ bodies. But, for the statistically minded, there was no interaction.

• Next they looked separately at the two developmental stages. Considering just infants first, younger infants looked at the ‘obese’ and ‘average’ pictures equally, but older infants looked longer at the ‘obese’ figures. This result wasn’t what had been expected and the authors suggested a possible explanation for it.

Infants and toddlers look at things for different reasons. In infants, familiarity and novelty probably explain most of what makes them look at something. Infants likely pay attention to familiar things, and lay down the neural memory and framework telling them that these things are familiar, or ‘normal’. Later, when they have a good idea of what is ‘normal’, they are likely to be curious about things that are not, that is, images with novelty value will draw their attention.

The authors pointed out that the range of BMIs in the ‘average’ photographs (the After pictures from the weight-loss contestants), was mostly similar to the local population, so these would have been more familiar. In contrast, only 2% of the NZ population falls into the ‘morbidly obese’ category with BMI over 40, so the Before photos would have some novelty value. The researchers suggested that for the very young infants, everything is new and so no differences emerged in looking times between the two photo sets; but for the older infants, the concept of ‘normal’ is more likely to be in place, and the novelty value of the very large bodies may have explained why they looked longer at those pictures.

• In toddlers, the opposite happened. The younger toddlers also looked about equally at the ‘obese’ and ‘average’ photos, but the older toddlers spent longer looking at the ‘average’ photos and less time looking at the ‘obese’ images.

The researchers noted that in toddlers, familiarity and novelty are unlikely to explain all of the differences in viewing times. These children are already somewhat socialised – and social attitudes will have started to be learned and will impact on behaviour. The authors hypothesised that although both sets of toddlers may have internalised societal aversion to fat bodies, the novelty value may still have played an attracting role, balancing out the two effects.

In the older toddlers, they hypothesised, the social effects seem to have won out. Because the researchers had hypothesised before they started that mothers’ anti-fat attitudes would explain preference against looking at heavier bodies, and because this group was the only one that actually displayed a preference toward ‘average’ bodies rather than ‘obese’ bodies, they looked at the relationship between mothers’ attitudes looking times in the older toddlers group. And the result was as predicted – mothers with higher anti-fat attitudes had toddlers who looked longer at images of ‘average’ than of ‘obese’ individuals (correlation, r=-.62, p=.008).

What it means

The results have to be interpreted with caution. We can try and explain the findings based on our knowledge of childhood developmental and psychology, but at best, we can say there appears to be an association between X and Y, and this might be the reason. This study also does not show anti-fat attitudes in toddlers; that would be reading too much into it. Looking more at one thing does not mean that they like it better. It is possible that the children just prefer to look at more familiar things; for example, in the ‘average’ sample, 50% of the bodies had BMIs in the ‘overweight’ category, which is very similar to the New Zealand national average of 42%. In the ‘obese’ sample, 50% were ‘obese’ by BMI standards, and the other 50% were ‘morbidly obese’. The corresponding figures in the NZ population are 28.5% and 2.5%, respectively. However, the fact that looking at the ‘average’ photos was associated with the mothers’ anti-fat attitudes certainly supports the researchers’ hypotheses.

Actual preference for thinner over fatter bodies has previously been shown in children as young as 3 years old. For example, in three studies with children aged 3 to 5, the children attributed more negative characteristics to a fat child than a thin one, and managed to explain their reasoning being due to the child’s weight by the age of 4. At all three ages, the kids least wanted to play with a fat child compared with an average or a thin child. Most of the children did prefer an average child to a thin child; except for the ‘overweight’ children. They had the most negative views of fat children than did lower-weight kids. How sad is it that as young as 3, they are already learning to devalue others who look like them. What are we teaching them?

Numerous other studies have replicated this finding – that dislike of fat starts very young. The present study may provide evidence for when the roots of these preferences are laid down. Kids may be picking up on societal anti-fat bias by age 2 1/2.