More on Perceptual Restoration

Last week's post on perceptual restoration in toddlers brought a lot of speculation from commenters. To answer some of the questions, I thought I'd elaborate a bit here on the phenomenon and how I created the demo.

First, here's the original recording again, with me saying "dinosaur" three times:

In the first case, I edited out the "s" sound, and everyone with normal hearing can hear that. The last "dinosaur" is complete. Did I edit out the "s" in the middle dinosaur?

Most adults believe they hear the "s" sound in cases like this, even if the sound has been edited out: the perceptual system adds in a sound where it doesn't exist.

Indeed, more than half of the respondents to our poll said they had heard an "s" sound, even though in fact the sound was edited out in the second "dinosaur."

But some commenters speculated that an "s" sound was embedded in the sneeze sound effect I created, thus nullifying the effect. The "sneeze" was actually a composite of a fake cough and a fake sneeze (neither sounded realistic enough on its own). Do you hear an "s" in either of these sounds?

Personally I'm not hearing it, but I agree that it's closer to an "s" sound than other sounds I could have inserted. In fact the authors of the study do point out that perceptual restoration doesn't always occur; it's less likely to occur when the inserted sound is less like the sound it replaces. As a demonstration, I've redone the demo below, using a horn sound instead of a sneeze:

Now do you hear the "s" in the second "dinosaur"? I certainly don't. So our commenters who argued that the sneeze sounded a little like an "s" do have some grounds for their belief, but I still think that some of what they thought was an "s" sound was in fact the perceptual restoration effect.

More like this

One of the amazing things about learning language is that children rarely hear language sounds in ideal acoustic environments. Maybe other people are talking in the background, or the dishwasher is running, or the TV is on. Yet somehow children they learn words just the same. By the time we're…
There is a growing body of evidence that very young children -- too young even to talk -- still know plenty of words. When our kids were very young, it was quite clear that they knew the meanings of many more words than they could actually produce. When they couldn't speak at all, they understood…
A study doesn't have to be brand-new to be interesting. Consider the situation in 1992: It was known that adults are much better at distinguishing between sounds used in their own language compared to other languages. Take the R and L sounds in English. In Japanese, both of these sounds belong in…
The fact that infants are able to learn language without any help from adults can sometimes seem almost miraculous. Not only do children learn to speak and understand language completely on their own, active teaching of language skills seems to make almost no difference in their ability to talk.…

You could run a spectrograph on the cough/sneeze sound and see if it contains the profile of "s" (high-frequency fricative). Humans do seem to map language sounds onto non-language sounds based on shared acoustic principles. You might disambiguate the interference sound from the linguistic "s" by using something with a lower frequency.

Yes, I did notice the 's' that seems to be actually missing in third clip. Looks like you should have chosen a horn rather than a fake sneeze/cough (or maybe even a different word, like infor_ation).