Violet Brown
May 2020

What do you work on?

I research all things related to how people process speech. Some of my focuses include how visual cues like seeing the talker affect speech recog­ni­tion, and the cog­ni­tive demands asso­ci­at­ed with pro­cess­ing speech in adverse lis­ten­ing conditions.

What did you do using Gorilla?

The McGurk effect is a com­mon­ly cited audio­vi­su­al illu­sion in which dis­crepant audi­to­ry and visual syl­la­bles can lead to a fused percept (e.g., audi­to­ry “ba” paired with visual “ga” is often per­ceived as “da”; McGurk & Mac­Don­ald, 1976).

To expe­ri­ence the effect first hand, watch this video. First listen to the video with your eyes closed, then watch it!

The McGurk effect is robust in pooled group data, but people differ in the extent to which they are sus­cep­ti­ble to the McGurk effect — some indi­vid­u­als always report the audi­to­ry syl­la­ble (they are ‘immune’) and others always report the visual syl­la­ble. What accounts for the difference?

Despite its preva­lence in the audio­vi­su­al speech per­cep­tion lit­er­a­ture, little is known about why people differ in their sus­cep­ti­bil­i­ty to the effect. Pre­vi­ous research sug­gests that better lipread­ers may be more sus­cep­ti­ble (Strand, Coop­er­man, Rowe, & Simen­stad, 2014), but other per­cep­tu­al and cog­ni­tive cor­re­lates have not been iden­ti­fied. In our study, we addressed whether McGurk sus­cep­ti­bil­i­ty is related to six poten­tial cor­re­lates: lipread­ing ability, ability to extract infor­ma­tion about place of artic­u­la­tion from the visual signal (this pro­vides us with a more fine-grained measure of lipread­ing ability), audi­to­ry per­cep­tu­al gra­di­en­cy (this is a measure of par­tic­i­pants’ ability to detect where an ambigu­ous syl­la­ble falls on a con­tin­u­um ranging from “da” to “ta”), atten­tion­al control, pro­cess­ing speed, and working memory capac­i­ty. We imple­ment­ed each of these tasks using Gorilla, and recruit­ed 206 par­tic­i­pants from Amazon Mechan­i­cal Turk.

All of our data, code for analy­ses, and mate­ri­als can be accessed at https://osf.io/gz862/, and details regard­ing our pre-reg­is­tered hypothe­ses, sample size, exclu­sion cri­te­ria, and analy­ses can be viewed at http://osf.io/us2xd/.

“Per­cep­tu­al and cog­ni­tive traits that are com­mon­ly used in indi­vid­ual dif­fer­ences studies appear to be unre­lat­ed to sus­cep­ti­bil­i­ty to the McGurk effect.”

What did you find?

We found that better lipread­ers tended to be more sus­cep­ti­ble to the McGurk effect (con­sis­tent with the results of Strand et al., 2014), but did not find evi­dence that any other per­cep­tu­al or cog­ni­tive abil­i­ties were asso­ci­at­ed with McGurk susceptibility.

These results suggest that a small amount of the vari­abil­i­ty in this classic audio­vi­su­al speech illu­sion is related to lipread­ing skill, and that other per­cep­tu­al and cog­ni­tive traits that are com­mon­ly used in indi­vid­ual dif­fer­ences studies appear to be unre­lat­ed to sus­cep­ti­bil­i­ty to the McGurk effect. The orig­i­nal paper on the McGurk effect has been cited over 6,000 times, so it is some­what sur­pris­ing that cor­re­lates of McGurk sus­cep­ti­bil­i­ty have not been iden­ti­fied in the pub­lished lit­er­a­ture. We suspect that this may be attrib­ut­able to pub­li­ca­tion bias, which can make it dif­fi­cult to publish null effects. This study is there­fore an impor­tant con­tri­bu­tion to the lit­er­a­ture, and may be par­tic­u­lar­ly useful for researchers attempt­ing to iden­ti­fy per­cep­tu­al and cog­ni­tive cor­re­lates of McGurk sus­cep­ti­bil­i­ty, which, as it turns out, remain elusive.

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

Given that we study speech per­cep­tion, we needed to ensure that par­tic­i­pants could actu­al­ly hear the audi­to­ry stimuli, so we required that they used head­phones during the experiment. To check that they were actu­al­ly fol­low­ing these instruc­tions, we imple­ment­ed a recent­ly-devel­oped head­phone check (Woods, Siegel, Traer, & McDer­mott, 2017). Par­tic­i­pants are pre­sent­ed six trials with three tones each, and on each trial, one of the tones is pre­sent­ed out of phase across stereo chan­nels. When lis­ten­ers are wearing head­phones, this tone sounds notice­ably quieter than the other two, but this dif­fer­ence is extreme­ly dif­fi­cult to detect when stimuli are pre­sent­ed through loud­speak­ers. If par­tic­i­pants incor­rect­ly iden­ti­fied the qui­etest tone in at least two of the six trials (i.e., they could get one of the six wrong), they were not allowed to advance to the actual experiment.

Has this study been published?

Yes, this study just came out in PLoS One. You can find it here.

“Con­duct­ing research online allows us to test whether the effects we’re inter­est­ed in are present in a more eco­log­i­cal­ly valid setting, and addi­tion­al­ly allows us to achieve a larger sample size than is typical in studies con­duct­ed in the lab.”

What is the most excit­ing piece of work or research you’ve ever done?

I’m really excited about all of my research, but one line of research that I’m espe­cial­ly excited about right now con­cerns the amount of effort that lis­ten­ers have to expend to rec­og­nize audio­vi­su­al speech. In a study that recent­ly came out in Psy­cho­nom­ic Bul­letin & Review, we showed that a mod­u­lat­ing circle does not improve speech recog­ni­tion, but it sub­stan­tial­ly reduces the effort nec­es­sary to do so (Strand, Brown, & Barbour, 2018).

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

As more methods are devel­oped to ensure good quality data (and detect bots), con­duct­ing research online will give us the means to effi­cient­ly collect data for high-powered studies. I think online research will play an impor­tant role in repli­ca­tion, because not only will more studies be con­duct­ed to test whether effects can repli­cate in an online sample, but the rapid rate of data col­lec­tion will also facil­i­tate the repli­ca­tion of studies that would oth­er­wise be time-con­sum­ing to conduct in the lab.

What is the biggest advan­tage of online research methods?

Most of our research is con­duct­ed on healthy, moti­vat­ed, normal-hearing college stu­dents. Though I would argue that our find­ings are usually gen­er­al­iz­able beyond this pop­u­la­tion, con­duct­ing research online allows us to test whether the effects we’re inter­est­ed in are present in a more eco­log­i­cal­ly valid setting, and addi­tion­al­ly allows us to achieve a larger sample size than is typical in studies con­duct­ed in the lab.

Why did you choose Gorilla?

We wanted to collect data through Amazon Mechan­i­cal Turk to ensure a large and diverse sample, and we needed a flex­i­ble online plat­form to design our experiment. The experiment we con­duct­ed had several tasks that varied in the types of stimuli we pre­sent­ed (e.g., videos with audio, audio-only stimuli, text), and Gorilla could effec­tive­ly present each of these stim­u­lus types.

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

Not only was Gorilla’s inter­face intu­itive, which enabled us to quickly and effec­tive­ly design our study, but this plat­form also allowed us to collect data from 206 par­tic­i­pants in just a few weeks for a rel­a­tive­ly low cost.

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

Given that we assessed indi­vid­ual dif­fer­ences in par­tic­i­pants’ abil­i­ties in six dif­fer­ent tasks, the stand-out feature in Gorilla was its flex­i­bil­i­ty in allow­ing us to admin­is­ter each of these tasks.

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

Julia Strand — my former under­grad­u­ate research mentor and current col­lab­o­ra­tor and dear friend — gets all the credit for instill­ing in me not only a fas­ci­na­tion with speech per­cep­tion, but also a love for research more gen­er­al­ly. I worked as an under­grad­u­ate research assis­tant in her lab through­out my time at Car­leton College, and was her lab manager for a little over a year after I grad­u­at­ed. Although I quickly devel­oped an inter­est in spoken word recog­ni­tion, what drew me in (and main­tained my inter­est) was Julia’s enthu­si­asm toward research and doing good, open science. It’s con­ta­gious, and luckily I caught the bug early. I couldn’t be more grate­ful to her.

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

I used to bartend at a craft dis­tillery in North­field, Min­neso­ta called Loon Liquors. The dis­tillery is “grain to glass,” which means they receive grain from local farms and turn it into their product on-site (rather than receiv­ing what’s known as “neutral grain spirit,” which is dis­tilled by another company), afford­ing them precise control over the quality and con­sis­ten­cy of the product. As a result, the bar­tenders learn to care­ful­ly con­struct cock­tails that per­fect­ly com­ple­ment the flavors in the spirits, and this has made me appre­ci­ate the art and science that goes into making a good drink. I really love bar­tend­ing, and although I don’t have time to bartend in grad­u­ate school, I still make cock­tails with my friends and teach them about the process.

Are there any online courses, pod­casts, dis­cus­sion groups or resources that you’d rec­om­mend to others?

I’d highly rec­om­mend the podcast The Black Goat with Simine Vazire, Sanjay Sri­vas­ta­va, and Alexa Tullett.

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

I loved reading The Seven Deadly Sins of Psy­chol­o­gy by Chris Cham­bers. This book clearly and effec­tive­ly lays out seven issues that are preva­lent in psy­cho­log­i­cal research and includes sug­ges­tions for how we can address these issues.

Violet Brown
Speech Perception
PhD student in Psychological and Brain Sciences
Washington University in St. Louis
Violet Brown

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