[pks016]

I work in the field. The main takeaway is zebra finches (maybe other songbirds) can discriminate vocalizations based on function, even if they sound similar.

Generally, birds can tell apart categories of sounds e.g. vocalizations from different individual birds, male vs female, call vs song, conspecific vs heterospecific etc. The question is if birds can do it for specific function e.g. agonistic calls vs non-agonistic calls. Simple question but way harder to test because of associated contextual info. with vocalizations.

The paper is culmination of last decade of work (includes many of the past works) but this is the new result.

[Aachen]

From https://www.jeremycollerfoundation.org/news-and-insights/pre... it sounds like the main takeaway is that they seem to conceptualise the sounds:

> the birds mistook long-distance contact calls and short-distance contact calls, which are acoustically very different. But, they never mistook a short contact call with a short alarm call, which have very similar acoustic patterns but entirely distinct meanings. As such, the study reveals that call perception elicits a mental imagery of the meaning of call-types, rather than triggering a reflexive response.

How do you see that?

[pks016]

Generally, you test birds in a series of discrimination experiments. So for this example, the discrimination task would be distance calls vs contact calls. Let's say, birds learn to discriminate between 20 distance calls vs 20 contact calls. They can learn this quickly (reward and punishment). After birds learned this rule (say 75% accuracy), we ask to generalize this by adding more calls. Now, birds have to discriminate 30 distance calls vs 30 contact calls (10 new for each). We can check now, for which new calls they are more likely to correct and incorrect response.

In this research field, we often perform this types of experiments (not this exact one). So, this is not that surprising to some of us. Birds also prioritize duration a lot when telling apart calls.

[computerdork]

Interesting! Could you break this down further? Maybe specific examples of what you're mentioning might help - for instance, what "similar-sounding calls with different functions" are zebra finches discriminating between? What exactly are different situations of these functions? How exactly (and through what experiments) did she determine this?

And I read the article (but not her research paper), and have a vague idea, but it's tough to get a full grasp - and if this is just too difficult to fully explain, no worries!

[pks016]

Yeah, the paper is indeed difficult to read (even for me). I read it a while back. I'll try to explain.

So, there are few things to know before and see what we're trying to prove. main thing: Categorical perception: (in short) brain perceive similar sounding sounds (say A and B) in a continuous manner, and in the continuum of two sound, there would be a point where one sound (A) will switch and sound like the other sound (B).

In zebra finches, let's take an example: distance call and tet call. Both these calls are contact calls, birds use them to keep in contact with other birds. Now, we need to extract the acoustic similarity between these two calls, and test birds in a experiment where we ask them to discriminate between these two call types (and get a learning curve; say trials vs probability of correct choice). Then, we can fit a theoretical model of categorical perception to see how well they fit both in acoustic and perceptual dimensions.

This is for one function (contact call), we can do this within other call types and between other call types. At the end, we can see how much of birds' performance is explained by acoustic dissimilarity, function of acoustic calls etc.

This is what the authors have done. They first performed LDA based classification on call type to obtain distance between call types, misclassification etc. (acoustic dimension). Birds went through a series of discrimination experiments based on call types (similar to what wrote above). Then, they compared/matched acoustic and perceptual dimension.

[computerdork]

Thanks for the explanation on this. Think I partially understand. Birds can distinguish calls on at least two characteristics, by the sound of it and by its function. And the authors have developed experiments to show that birds can do both. Is this correct or did I get on the wrong track?

[pks016]

Yes. Kind of. They showed that birds can do function/meaning of calls (e.g., contact call group) using the meaning not other cues (e.g. duration, acoustic similarity of calls etc.).

[computerdork]

Ah okay, thanks!