One of the craziest and funniest hypotheses I have recently come across is Tomer Ullman’s attempt to explain screaming babies in terms of an evolutionary advantage. If you have seven spare minutes I recommend watching it. He suggests that ‘infant stress vocalizations’ were used to motivate fighting – that babies were attached in baby carriers to the backs of warriors and brought into battle because their crying was just so unbearably agonizing. Whist this sounds a little far fetched, another point in this talk is worth thinking about. He argues that the estimated rate of infanticide in Palaeolithic societies at around 15-20 % correlates neatly with the rate of high-need babies in modern societies. Cry babies might just have been killed some time shortly after birth. An interesting theory, if impossible to prove.
In any case, it makes for a refreshing alternative to the usual explanations of infanticide – population control, sex selection, resource competition, parental mental illness and the like. These rationalisations never sounded very convincing to me. After all, even without further ado it was hard enough to keep the offspring alive. They also do not account for emotional bonds between mothers and children with babies behaving normally – granted that these bonds are likely to have developed over time rather than being instantly present at birth.
It is also difficult to estimate the scale of infanticide in prehistoric societies. We can usually not ascertain the cause of death of buried babies by anthropological methods. Birth injuries, genetic defects, malnutrition, infections and other health problems are just as likely causes of death as infanticide or targeted neglect. We have plenty of evidence from the Classical World that unwanted children were simply abandoned, leaving the chance that they would be adopted by others. A number of mythological stories revolve around this theme, not least the foundation of Rome. Newborns were brought to the father who decided whether the child was to be kept and raised – or left to die.
Tomer Ullman’s hypothesis made me think of another peak in childhood mortality between two and three years that we see in prehistoric cemeteries. It is normally explained by weaning, as the end of the breastfeeding period causes decreased resistance to infections, worse nutrition and problems with food hygiene. The age also neatly correlates with the notoriously difficult toddler years. What if just very impossible, defiant and constantly misbehaving toddlers were killed? I wouldn’t be terribly surprised. Thank goodness that toddlers make up for their behaviour with their cuteness!