Auditory processing test — where hearing stops and listening starts

Because the number it produces would be a fact about your laptop. A speech reception threshold is a signal-to-noise ratio measured through calibrated transducers at a known presentation level. A browser controls neither the output level nor the headphones, and the visitor's volume slider moves the answer, so the same person produces different thresholds on different laptops. There is a second obstacle that is specific to a web page: the browser's speech synthesizer writes straight to the output device rather than into the audio graph, so a synthesized voice cannot be mixed with a masking noise at a ratio the page controls — and a speech-in-noise task whose ratio drifts with the voice is not a test of anything. The three blocks that are here were chosen because their ratios and intervals are internal to the page: 2 ms of silence is 2 ms of silence whatever your volume slider says.

No, and the reverse is more useful: a poor one here rarely means anything, while a good one rules out very little. Temporal resolution is one narrow property of the auditory system, measured on one kind of stimulus, and the clinical batteries use four to six subtests precisely because no single one of them is diagnostic. A person who finds 3 ms silences easily may still lose the third word of a sentence in a busy room, because that failure involves working memory, attention and the linguistic prediction that fills gaps in — none of which this page touches.

The first two blocks work on speakers; the third one does not. A gap in a burst and a pattern of three tones are the same stimulus whichever way they reach you, provided the level is high enough that a few milliseconds of silence is not lost under room noise. The ear block is different in kind: it sends one contour left and another right at the same instant, and a pair of desk speakers delivers both to both ears with a delay and a level difference that varies with how you are sitting. That is why the check gates that block alone, and why passing it on speakers is still a reason to put headphones on.

Because counting is a different and much easier operation than ordering. Two of the six sequences on this page contain two high tones and one low; a listener who only registers the census answers those two with a coin flip. Order is also the part that the clinical version of this task was built around — a pattern is presented and the patient repeats it back — and the reason the task survives normal hearing thresholds is that every tone in it is perfectly audible. Nothing here is quiet or masked. The difficulty is entirely in holding three events in sequence for two seconds.

With six trials an ear, almost certainly nothing — the two intervals printed beside those counts overlap so heavily that a two-trial difference is noise, and the page says so beside the figures. A real and repeatable ear difference is worth knowing about, and the classic finding is that it depends on what is being played: Kimura (1967) established a right-ear advantage for dichotic speech, while Kimura (1964) found the opposite for melodies, since the two kinds of material are handled by different hemispheres. Tonal contours sit closer to the melody case. If the asymmetry holds up over several runs, an audiologist can measure it with dichotic material that has norms behind it.

No page can, and a page that offers to is the reason this one says so above the results rather than beneath them. The diagnosis requires a booth, calibrated transducers, an audiologist and a battery administered in a fixed order, partly because several of the subtests are only interpretable once normal hearing thresholds have been established first — a child who mishears because they cannot hear is a different finding with a different remedy. It also depends on age: temporal resolution and pattern reporting both mature through childhood, so an adult reference figure is the wrong yardstick for a young child. What this page can honestly offer a parent is the shape of the tasks, so that an appointment is less strange when it happens.

Because a total needs weights, and weights come from a normative sample this page does not have. A clinical battery can combine its subtests because each one was standardized on a known population and the combination rule was validated against a criterion; multiplying a gap threshold in milliseconds by a percentage of patterns and an ear score would require deciding how many milliseconds a pattern is worth, and any answer to that would be invented. The three-figure output is also more useful: the interesting result in this area is nearly always which task fell behind, not how a mixture of them averaged.