Answer:
A)difference threshold, or just noticeable difference
Explanation:
This question is missing its options. The options for this question are:
A)difference threshold, or just noticeable difference.
B)absolute threshold, or average absolute threshold.
C)subliminal threshold.
D)Weber's threshold.
In psychology, the term threshold refers to the strength that a stimulus must reach to be detected by a person.
More so, the term difference threshold (or just noticeable difference) then refers to the minimum difference in stimulation (like lights, sounds, etc) that a person can detect 50 percent of the time.
In this example, there are 2 stimuli (tones) that are slightly different but that more than half the time the group rated them as being the same. We can therefore say that they lack difference threshold (the minimum difference between them to actually be perceived) and that's why they were rated the same.