Folk, Hull Truck Theatre, Hull, 2pm and 7.30pm today; Opening Skinner's Box, 2.30pm and 7.45pm today. Box office: Hull, 01482 323638 or hulltruck.co.uk; Leeds, 0113 213 7700 or wyp.org.uk HULL playwright Tom Wells was in the house the other night, low key under his woolly hat, unassuming and smiling as he talked in the foyer after the performance.

His plays are in his mould; they don't shout from the rafters; they are not demonstrative or brash or attention seeking, but stealthily they catch the essence of everyday life, the way ordinary folk live, you could say.

Hence the title of his latest comedy drama, Folk, which also refers to his love of folk music that goes back to his own days of performing in a band in Withernsea.

Irrepressible Irish nun Winnie (Connie Walker) is vigorously enjoying her latest singing session at her home with guitar-playing, socially cautious Stephen (Patrick Bridgman) when a brick crashes through the window in Bob Bailey's open-plan design. Winnie demands that the miscreant should come in, and so enters shifty Kayleigh (Chloe Harris), 15 and angry after moping around all day at a funeral of someone she knows but "wouldn't call a friend".

Piece by piece, under the astute direction of Birmingham Repertory Theatre's Tessa Walker, Wells builds the back story of all three. Each revelation is quietly devastating rather than explosive, but still as impactful, and further elucidated by a familiar folk song, whether Dirty Old Town, sung by Harris's emotionally mangled Kayleigh, or The Pogues' If I Should Fall From Grace With God, a song so apt for Wells's humorous yet moving play.

On tour in Leeds, Improbable artistic directors Phelim McDermott and Lee Simpson are considering how religion and philosophy ruled the way we thought about love, killing, memory, our beliefs and the way we learn until science joined the debate a hundred years ago to reveal that "pretty much everything we think about ourselves is wrong".

Taking Lauren Slater's book as starting point, Opening Skinner's Box uses an ensemble cast of six in brown suits and bow ties to play out ten psychological experiments and tell each exponent's story in a linear, episodic work that seeks to make sense of who and what we are. The structure is methodical, but not academically dry, and the effect is accumulative and increasingly fascinating, while the show constantly reminds us of the osmosis between art and science that theatre involves.

Folk, Hull Truck Theatre, Hull, tonight at 7.30pm, tomorrow at 2pm and 7.30pm; Opening Skinner's Box, West Yorkshire Playhouse, Leeds, tonight at 7.45pm, tomorrow at 2.30pm and 7.45pm. Box office: Hull, 01482 323638 or hulltruck.co.uk; Leeds, 0113 213 7700 or wyp.org.uk