Answer:
A hub is a multi-port repeater, which means any signal from any connection is repeated to all other ports on the hub. This leads to more collisions as a result.
A switch is a multi-port bridge, and contains packet switching so that the message is only switched out the port of the destination device, not across all ports. Thus, the collisions are very small.
Switches and hubs can be used interchangeably in a network, with performance differences. The network does not know the difference.