Final answer:
The differential threshold refers to the difference between what two organisms can detect through the same sensory channel. Dogs can hear sounds of far higher frequency than humans, with a range up to about 30,000 Hz compared to humans' range of 20-20,000 Hz.
Step-by-step explanation:
The differential threshold refers to the difference between two organisms, such as a person and a dog, in their ability to detect different stimuli through the same sensory channel. In this case, it refers to the difference in the frequencies of sounds that humans and dogs can hear. Dogs can hear sounds of far higher frequency than humans, with a hearing range up to about 30,000 Hz compared to humans' range of 20-20,000 Hz. This means that dogs can hear sounds that are beyond the range of human hearing, such as the sound of a dog whistle.