Halliday & Matthiessen (1999: 84):
The most favoured ‘band’ in delicacy is that of the basic level: it is taxonomically most highly elaborated, it tends to be learnt first by children, and it construes categories with syndromes of usually salient functional and perceptual properties. […] It has been pointed out that basic level categories are most distinct in terms of how human beings interact with them.