Nadine Lavan
December 2019

What do you work on?

I study voice iden­ti­ty per­cep­tion, that is I look at how we recog­nise famil­iar voic­es, how we dis­crim­i­nate between unfa­mil­iar voic­es and also how we learn new voice identities.

“Peo­ple must have indeed formed a rep­re­sen­ta­tion based abstract­ing voice-spe­cif­ic aver­ages as opposed to the trained exemplars.”

What did you do using Gorilla?

I have run quite a few stud­ies on Gorilla by now. One of the first stud­ies I ran was try­ing to work out how peo­ple form rep­re­sen­ta­tions of newly learned voice iden­ti­ties. When we hear voic­es in every­day life, one strik­ing fea­ture of these voic­es is their with­in-per­son vari­abil­i­ty: the voice of the same per­son will sound dif­fer­ent depend­ing on each con­ver­sa­tion part­ner, speak­ing sit­u­a­tion and speak­ing envi­ron­ment (e.g. giv­ing a job inter­view ver­sus talk­ing to a friend ver­sus shout­ing at the pho­to­copi­er). Despite this with­in-per­son vari­abil­i­ty, we can recog­nise famil­iar voic­es with rea­son­able reli­a­bil­i­ty. So, how do we make sense of all of this vari­able and poten­tial­ly messy input? There are pro­pos­als in the face and voice iden­ti­ty per­cep­tion lit­er­a­ture sug­gest­ing that peo­ple form rep­re­sen­ta­tions when learn­ing new iden­ti­ties that are based on abstract­ing the aver­ages of all expe­ri­enced instances of that face or voice.

In order to test this pre­dic­tion, we decid­ed to train lis­ten­ers to learn to recog­nise – and thus form a rep­re­sen­ta­tion of – 3 voice iden­ti­ties. The acoustic prop­er­ties of the train­ing stim­uli were care­ful­ly manip­u­lat­ed such that each voice’s train­ing stim­uli formed a dis­tri­b­u­tion that was miss­ing its cen­tre. So, in this set up, lis­ten­ers never heard the aver­age acoustic prop­er­ties of the voic­es dur­ing training.

At test, we then pre­sent­ed lis­ten­ers with novel record­ings of the 3 trained iden­ti­ties that mapped onto the acoustic prop­er­ties they had heard dur­ing train­ing. Cru­cial­ly, we also now pre­sent­ed lis­ten­ers with record­ings that fell onto the aver­age of the train­ing dis­tri­b­u­tions. If aver­ages are indeed abstract­ed dur­ing iden­ti­ty learn­ing, we would expect that lis­ten­ers are as good or even bet­ter at recog­nis­ing the trained iden­ti­ties from these aver­age record­ings com­pared to the other recordings.

What did you find?

And this is exact­ly what we found: Lis­ten­ers were more accu­rate at recog­nis­ing the record­ings that cor­re­spond­ed to the unheard (!) aver­age than the record­ings that fell onto the pre­vi­ous­ly heard train­ing dis­tri­b­u­tion. We could also show in a com­ple­men­tary analy­sis that accu­ra­cy in fact increased the clos­er a record­ing was to the aver­age in terms of its acoustic prop­er­ties. We took these find­ings as an indi­ca­tion that peo­ple must have indeed formed a rep­re­sen­ta­tion based abstract­ing voice-spe­cif­ic aver­ages as opposed to the trained exemplars.

We are now look­ing into run­ning fol­low-up exper­i­ments to find out more about the under­ly­ing mech­a­nisms that may be under­pin­ning these findings.

“It is amaz­ing how quick­ly any­one can set up a study from scratch.”

Has this study been published?

Our arti­cle has been pub­lished by Nature Com­mu­ni­ca­tions.

How did Gorilla make your life or research bet­ter, eas­i­er or faster?

Switch­ing to online test­ing with Gorilla made a huge dif­fer­ence to me. It saved me time and has­sle when set­ting up exper­i­ments and stud­ies. There are also essen­tial­ly no com­pat­i­bil­i­ty issues when switch­ing com­put­ers or shar­ing stud­ies. Addi­tion­al­ly, I sud­den­ly had access to par­tic­i­pants through­out the year, which had pre­vi­ous­ly been an issue.

What is the biggest advan­tage of online research methods?

By hav­ing my study online run­ning in a brows­er, it now takes me one after­noon to col­lect my data as opposed to hav­ing to test in per­son for weeks and weeks.

How do you think online research is going to change your field?

It will be a lot eas­i­er to get ade­quate sam­ple sizes when test­ing online, which improves the qual­i­ty of research.

Did you include any spe­cial fea­tures in your study to ensure good qual­i­ty data? If so, what did you do?

Our stud­ies usu­al­ly involve play­ing sounds to peo­ple, so we always need to make sure peo­ple can actu­al­ly hear our stim­uli. There is a use­ful screen­ing (Woods, Siegel, Traer & McDer­mott, 2017) that we use at the start of our stud­ies to make sure that peo­ple are wear­ing head­phones and are not lis­ten­ing to our record­ings on tinny lap­top speak­ers. Through­out our tasks we also use audi­to­ry atten­tion checks to make sure peo­ple keep on pay­ing atten­tion. These checks usu­al­ly take the form of catch tri­als where instead of play­ing one of our exper­i­men­tal stim­uli, we present a record­ing that is instruct­ing par­tic­i­pants to pick a cer­tain response for this par­tic­u­lar trial (e.g. “Please press 7 now”).

For you, what is the stand-out fea­ture in Gorilla?

It is real­ly easy and intu­itive to use Gorilla. It is amaz­ing how quick­ly any­one can set up a study from scratch. This is not only use­ful for my own stud­ies but now stu­dents can eas­i­ly cre­ate their own tasks for their research projects, which helps to real­ly get to grips with their experiments.

Who or what orig­i­nal­ly inspired you to work in your field of research?

For my under­grad­u­ate, I stud­ied lin­guis­tics and pho­net­ics, which set me off on the path of doing audi­to­ry research. How did I get inter­est­ed in this some­what niche field? Well – I watched My Fair Lady when I was a teenager…

When you’re not work­ing, what do you enjoy doing?

Cycling, try­ing to find the deli­cious cin­na­mon buns or almond crois­sants in town.

What sci­ence book have you read recent­ly that you’d rec­om­mend to others?

Not nec­es­sar­i­ly a tra­di­tion­al (pop) sci­ence book but The Feath­er Thief by Kirk Wal­lace John­son was an inter­est­ing read. I know a lot more about early nat­u­ral­ists, the exot­ic feath­er trade and fly tying after read­ing it!

 

Nadine Lavan
Voice perception research
Post Doc
UCL
Nadine Lavan

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