[SMARTY]

I wonder what the author means by ‘middle age’ in describing the remains of individuals found there.

‘Middle age’ in our understanding, I thought, would be ‘old age’ in ancient cultures.

The general population was low to begin with ... infant mortality was incredibly high and death from disease, fighting, etc. usually took an immense toll on populations as well.

I remember reading that age 45 could be regarded as ‘old age’ in ancient cultures. Considering this, Eric Hoffer said that 'history was made by juvenile delinquents...'

[Sherman Logan]

I remember reading that age 45 could be regarded as ‘old age’ in ancient cultures.

Nope. Old age pretty much meant then what it does now. The Bible refers to 70 or 80 years as expected lifespan.

Death rates were higher at all age levels then than now, especially in infancy and childhood.

IOW, fewer people as a percentage of total population were at any given time in the "middle age" and "old" categories, but viewpoints of who was in these groups weren't much different from today.