I'd love to see some evidence for that quote. This assertion paints individualism as a social rather than biological construct, and it's not obvious to me that this is true.
Even still, there are many pieces of evidence that seem to suggest social rather than individualist roots. We (meaning normal, functional human beings) all have the ability from a young age to sympathize with others. We have a strong desire to be part of a group. We feel guilt when we do something socially wrong. Intimate relationships release endorphins that give us pleasure. Language itself is only necessary in a strongly social species.
Honestly, I can't fathom human society as it is today beginning from small, isolated groups of people who are strong individualists. Only a select few of us can survive happily by ourselves, and I suspect that's been true for millennia. Our ability to cooperate and evolve socially, as opposed to biologically, is what has allowed us to become the most dominant species on Earth.
For example the earliest traders slid between bandits and merchants largely based on how strong you where. Or consider traditional views on corporal punishment. Violently beating ones family members was considered normal and proper let alone what society at large would do to people.