I didn’t know if my family had a connection to the white pueblo. But by living in its labyrinth of narrow cobblestone streets, I hoped to understand the fears that shaped the secret lives of my own family.

History is a part of daily life in the old quarter, where Inquisition trials were staged and neighbors spied on neighbors, dutifully reporting heretics — Christian converts who were secretly practicing Judaism. The former Jewish quarter, where white houses plunge down a steep, silvery lane, is still standing, though unmarked by any street sign. I wanted to understand why my family guarded secret identities for generations with such inexplicable fear and caution. When my aunt died a few years ago, she left instructions barring a priest from presiding over her funeral; my grandmother did the same.

There are scientific studies exploring whether the history of our ancestors is somehow a part of us, inherited in unexpected ways through a vast chemical network in our cells that controls genes, switching them on and off. At the heart of the field, known as epigenetics, is the notion that genes have memory and that the lives of our grandparents — what they breathed, saw and ate — can directly affect us decades later.

Recent studies in Sweden explore the effects of famine and abundant harvests on the health of descendants four generations later. That is not exactly what I am looking for: I’m intrigued by the notion that generations pass on particular survival skills and an unconscious sense of identity that stands the test of centuries.

The French psychologist Anne Ancelin Schützenberger, now in her 90s, has spent decades studying what she calls the ancestor syndrome — that we are links in a chain of generations, unconsciously affected by their suffering or unfinished business until we acknowledge the past.