This is an important theory when looking at the domestic division of labour from a functionalist perspective. Parsons (1955) argues that in the nuclear family the husband and wife have different separate roles to play.
Parsons (1955) argues that the division of labour is in terms of the husband playing an 'instrumental' role which means focusing on achieving success at work to be the breadwinner for the family and focusing on the financial needs of the family.
The wife plays an 'expressive' role which is focused on looking after the children and household and focusing on the family in terms of emotional needs. Parsons (1955) argues that this model fits because women are natually suited to nurturing the family and men are naturally suited to be a provider for the family.
This theory is highly criticised by the feminist perspective that argues that there is nothing natural about this model of division of labour and it just benefits men.