http://www.iser.essex.ac.uk/2012/03/18/feeding-your-baby-on-demand-may-lead-to-higher-iq
“This is significant because the mothers who tried but did not manage to feed to a schedule are similar to schedule-feeding mothers in that they tend to be younger, more likely to be single, more likely to be social tenants and likely to be less well-educated or to read to their child. These social characteristics are all understood to increase a child’s likelihood of performing less well at school."