This intrusion acts as the catalyst that disrupts Gifty’s carefully calibrated world, confronting her with the traumatic memories she has been trying to avoid. But Gifty’s attention has been diverted away from her experiment because her mother has come to stay, having had a relapse of the severe depression that she has experienced since the death of Gifty’s brother, Nana, by overdose. Using optogenetics, she is attempting to identify which neurons are “firing or not firing” whenever they decide to press the lever: “The mice who can’t stop pushing the lever, even after being shocked dozens of times are, neurologically, the ones who are the most interesting to me,” she says. Gifty is a PhD candidate at Stanford University who is conducting a study on the “neural circuits of reward-seeking behaviour” in mice by addicting them to a sugary energy drink and caging them in a behavioural testing chamber fitted with a lever that administers either the drink or a randomised electric shock. Yaa Gyasi, whose triumphant debut Homegoingwas published in 2016, demonstrates the marvellous truth of this in her new novel, Transcendent Kingdom, which shifts between clinical rigour and lyrical attentiveness as it tries “to make meaning” of one woman’s life.

M arianne Moore once suggested that poets and scientists work analogously, not only because each is willing to “waste effort” but because each “is attentive to clues, each must narrow the choice, must strive for precision”.

Transcendent novel