Scenario 1 – Children's Hearing

You find yourself working in a hospital checking the hearing of young children. Part of your role is to measure the absolute threshold of hearing to ensure they are developing normally. Your test involves presenting a 50Hz tone at several levels of loudness (dB level) and asking the child whether they heard something or not. You adopt the Method of Constant Stimuli, presenting the different loudness levels 25 times each.

The first child you see presented with the following results:

Loudness of the tone (dB)	2	4	6	8	10	12	14	16	18
% yes (heard) responses	0.08	0.16	0.28	0.44	0.6	0.76	0.88	0.96	1.0

Plot a psychometric function from this data.

Estimate the absolute threshold of hearing for this child based on this single tone.

The second child you see that day had experienced some trauma earlier in their life. You measured their hearing using the same approach and recorded the following responses:

Loudness of the tone (dB)	2	4	6	8	10	12	14	16	18
% yes (heard) responses	0.04	0.08	0.08	0.19	0.4	0.53	0.76	0.97	1.0

Plot a psychometric function of the data for this second child.

Estimate their absolute threshold of hearing.

Based on your findings, which child has the more sensitive hearing? Provide a brief explanation of your decision.

How many trials are presented to calculate the threshold using this approach?

You have been asked to develop a new test that will provide you with a threshold estimate but will not take as long as the current method. Outline an approach that you might adopt giving a reason for your choice.