Just Noticeable Difference (JND)

for Three Frequencies

 

 

Look about the room you are in and think about what you are perceiving.  

 

Our intuitions suggest abrupt thresholds--you either perceive something or you do not. If this is true, than a discrimination function for detecting a change in frequency, which we perceive as pitch, would look like the graph to the right. A discrimination task asks the participant to say whether or not two stimuli, in this case tones, are the same or different.  "Same" responses are recorded as 0, "different" responses as 1.  If perception is indeed binary and discreet, than a sudden shift would occur. In other words, you would quite suddenly hear that the two tones were different.  Is this truly the case? To examine this, participate in the following discrimination task using three different tones.  Will your perception be sudden, allowing you to tell absolutely and reliably when a change occurs between tone 1 and tone 2?

 

 

Taking the test...

Listen to the trials as many times as you like, and then check whether the two tones are the same or different.  When you are comfortable with the task, feel free to listen only once to each trial.  After you complete each set, press the "Register" button beside the table to view your results.  Don't worry about saying "same" or "different" an equal number of times, just mark whether or you not you hear the tones as the same, or different.  Once you have completed the discrimination task at all three frequencies, you will be graphing your responses as a function of frequency (details to follow task).

 

Medium Frequency JND

                                               

 

     

Test

Same

Diff.

 

Test

Same

Diff.

 

Test

Same

Diff.

 

               

 

 

 

 

Trial #1

 

Trial #8

 

Trial #15

 

 

 

 

       

 

 

 

 

Trial #2

 

Trial #9

 

Trial #16

 

 

 

 

 

       

 

 

 

 

Trial #3

 

Trial #10

 

Trial #17

 

 

 

 

your data...

Frequency

 

 

Response

 

 

 

 

Trial #4

 

Trial #11

 

Trial #18

 

 

 

 

 

 

 

 

Trial #5

 

Trial #12

 

Trial #19

 

 

 

 

 

 

 

 

Trial #6

 

Trial #13

 

Trial #20

 

 

 

 

 

 

 

 

Trial #7

 

Trial #14

 

Trial #21

 

 

 

 

 

                                           
                                     
                                               

 

 

High Frequency JND

                                               
     

 

Test

Same

Diff.

 

Test

Same

Diff.

 

Test

Same

Diff.

 

               
     

 

Trial #1

 

Trial #8

 

Trial #15

 

             
     

 

Trial #2

 

Trial #9

 

Trial #16

 

               
     

 

Trial #3

 

Trial #10

 

Trial #17

 

     

your data...

Frequency

 

 

Response

       
     

 

Trial #4

 

Trial #11

 

Trial #18

 

             
     

 

Trial #5

 

Trial #12

 

Trial #19

 

             
     

 

Trial #6

 

Trial #13

 

Trial #20

 

             
     

 

Trial #7

 

Trial #14

 

Trial #21

 

             
     

 

 

 

 

 

 

 

 

 

 

 

 

 

             
                                     
                                               

 

 

Low Frequency JND

                                               
     

 

Test

Same

Diff.

 

Test

Same

Diff.

 

Test

Same

Diff.

 

               
     

 

Trial #1

 

Trial #8

 

Trial #15

 

             
     

 

Trial #2

 

Trial #9

 

Trial #16

 

               
     

 

Trial #3

 

Trial #10

 

Trial #17

 

     

your data...

Frequency

 

 

Response

       
     

 

Trial #4

 

Trial #11

 

Trial #18

 

             
     

 

Trial #5

 

Trial #12

 

Trial #19

 

             
     

 

Trial #6

 

Trial #13

 

Trial #20

 

             
     

 

Trial #7

 

Trial #14

 

Trial #21

 

             
     

 

 

 

 

 

 

 

 

 

 

 

 

 

             
                                     
                                               

 

Results & Discussion

To graph your responses, you will need to copy and paste each column into the graphing program of your choice.  For each JND task, the first column contains the physical change presented (in Hz) and the second column records how many times you said that the two tones were the "different" (out of three possible).  The data are presented sorted by physical change, not in the order you responded.  The steady tone for the Medium frequency was 440 Hz, for the High frequency was 1760 Hz, and was 110 Hz for the low frequency.