Yes , you lay hardwood perpendicular to the joists.

Most wood flooring is attached to the plywood, not the joists. Many installations are glued down, sometimes nailed additionally. I think what's most important is how it will look in the room. The direction can really enhance the size and feel of a room. You should not limit yourself to the joist direction. Additionally, I like to consider how the wood floor interacts with the stairs, because it is a good safety measure to have the wood at the floor level be perpendicular to the treads, because it is easier for some people to see where the stair stop and start.

Hardwoods floors need to be laid perpendicular to the joists , not because they are attached to the joists but because the joists support the weight of furniture, walking on them etc.

True, solid hardwood flooring is usually installed perpendicular to the joist.

Some people say "hardwood" when they mean laminate, and engineered is hardwood, but not solid. Engineered or laminate can be laid however you wish because they are they are the type of flooring that is usually glued down or float.