Biological Anthropologist Professor Barry Bogin has delved into historical records on height ranging from the 1800s to the 1990s and analysed how height changes with economic conditions.

Published in a review in the Journal of Physiological Anthropology, Professor Bogin’s deep-dive concludes that a “lack of love and/or hope delays growth, disturbs development and maturation, and can even kill”.

He defines ‘love and hope’ as “the security and positive emotional intensity of the network of social relationships that all people need” and the “ability to see ourselves in a better world”.

Professor Bogin says he found the association between human growth in height with love and hope in multiple cases from across the decades.

He says that people born during economic recessions – such as the ‘Long Depression’ of 1873–1896 (a worldwide wages and unemployment recession) and pre-1970 Japan (before social, political, and economic changes reduced social inequalities) – were shorter as adults compared with people born during more prosperous times.

When looking at records spanning over 300 years on infants left in children’s homes, orphanages, and similar institutions, Professor Bogin found that children often experienced poor physical and mental development and high rates of death.

He also discovered that when people and children left hardship or experienced increased levels of love and/or hope their height increased. Professor Bogin observed this trend in data relating to adopted children, international migration, and colonial Europeans of the 19th and early 20th centuries.

When explaining the findings, Professor Bogin said: “Love and hope play essential roles in helping people grow in a healthy way. They come together in intricate ways to help us feel emotionally well.

“When we don't have love or hope, we experience toxic emotional stress, which has harmful biological effects, including blocking hormones needed for growth and height.

“Insecurity and emotional stress can kill, with the most notorious example being the very high death rates in orphanages throughout European history.  

“In the city of New York in the 1920s, nearly all infants under two-years-old in children’s homes died. They received food and basic sanitary care, but they did not receive any love or attachment to another person.

“The human species requires strong social and emotional attachments, that is love, between younger and older people; indeed, between people of all ages.

“These attachments are required to promote nearly all biological functions, such as food digestion and absorption into the body, a good immune system, and an overall happiness and positive outlook on life.”

Professor Bogin explained that this review is part of his research aimed at improving understanding of the factors behind insufficient height gain and excessive weight gain among millions of infants and children worldwide.

He said: “Most of the children with growth problems live in societies with tremendous social, economic, and political inequalities. These societies are often violent. 

“The fear generated by the inequalities and violence creates an emotional burden that slows growth in height and, at the same time, promotes growth in weight. 

“We need new interventions to tackle the fear of the inequalities and violence and I hope my research can promote changes in social economic and political policies for a fairer and more peaceful world.”

Professor Bogin’s review, titled ‘What makes people grow? Love and hope’, can be read in full online.