Apple has commissioned research to confirm the so-called 'iPod halo' effect, a report claims.

It appears the company has hired research firm, Advanis, to survey existing iTunes Store users to figure out their buying preferences and how they use the store. It asks users how they find using iTunes, what sort of music they prefer, and what kind of music player they use.

The survey also carries questions about future computer purchasing decisions: whether they use Mac or Windows; whether they plan to buy a new computer; and so on.

The survey is expected to be completed next month, and could provide the first hard evidence to confirm that happy iPod customers are more likely to buy an Apple Mac the next time they need to buy a computer.