Deutsch and Deutsch's late selection model of attention suggests that in a dichotic listening task:

a.

The bottleneck is in the form of an attenuator

b.

Only the attended, but not unattended, message is processed to the level of physical characteristics

c.

Only the attended, but not unattended, message is processed to the level of meaning

d.

The bottleneck is in the form of an all-or-none filter

e.

Both the attended and unattended messages are processed to the level of meaning