Uneasy listening: Kathryn Joseph, at Summerhall, reviewed

I have always been fascinated by artists who bounce between tonal extremes when performing, particularly the ones who serve their songs sad and their stagecraft salty.

Adele, for example, fills the space between each plushily upholstered soul-baring ballad by transforming into a saucy end-of-pier variety act, coo-cooing at the crowd and cursing like a squaddie. John Lennon gurned and clowned his way through the Beatles’ concerts, subverting the naked suicidal plea of ‘Help!’ in the process. John Martyn would belch and joust in mock-Cockney at the conclusion of a particularly sensitive piece. Jackie Leven punctuated songs of immense pain and sadness with eye-watering stories of defecating in alleyways and getting blootered with the Dalai Lama’s bodyguard.

A bipolar approach to performance can puncture reverence, acting as a knee-jerk spasm against stifling solemnity. It can also be deployed as a defence mechanism to protect overly exposed nerve endings.