Why 300ms?


300ms (read 300 milliseconds) simply refers to the short timing it takes to form a first impression of someone one just met. Every day we encounter hundreds of new persons, new faces, new voices. An extremely large quantity of information has to be processed by the cognitive system. 

In the 1950s, cognitive scientists suggested that our cognitive system is able to filter the incoming stream of information, in order to give priority to some stimuli over others. This is known as “selective attention” (for a review, see Driver, 2001)¹. 

In studies using neuro-imagery measures (Electroencephalography) to better understand the fine-timing behind perception, 300ms has been found to be a marker at which self-relevant stimuli started being differentiated from stimuli that are not crucial to the perceiver² . This stems from a specific attention that is given to a stimulus holding a functional value to the person who perceives it. 

In the recent years, a growing interest has raised regarding how humans attend their social world. Indeed, social objects hold highly informative value for decision-making. 


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FAQ – 300ms technicalities

It's simple. First, you need to create an account, then in your personal page you can record your voice (one word:"hello"). It will automatically be displayed to other members who can evaluate it on ten personality scales. You will see graphics of averaged scores in your personal page.

No, because there is no way of knowing how true what listeners perceive is. In personality tests, the aim is to measure how a person scores on scales that are assumed to represent the observed quality. Here, there is no such assumption, as the result is only a representation of others' perception.  However, it's fun to know how others (in an averaged way) perceive our voice, and how we can go further from that.

Yes. You can either delete your account or your recording at any time, with immediate effect. All associated data will be permanently erased.

Soon it will be possible! We are working on ways to make it available.

Just your phone, or a computer with a microphone. Of course it's better to record in a quiet place.

That's the trick. First impressions are fast and approximative. Past research has used the word "hello" before, and observed that single words conveyed sufficient ground for a first appraisal of vocal characteristics. Typically, it is observed that voices are rapidly assessed on two dimensions by perceivers: first, on how pleasing they are (positive, or negative). That's called valence. The second dimension is their capability of acting on this, how much of a threat or benefit they represent. It is sometimes called competence, or dominance. First impressions are a cognitive mechanism that is not necessarily true to reality, nor accurate, but it does help perceivers adapt their approach or avoidance behaviors in a world full of unknown signals.

It means that your voice likely belong to the highlighted categories when people don't know you and hear you for the first time. Without more information regarding your personality or even physical aspect, heuristic judgement is derived from the voice only. Again, it doesn't mean it represents who you are. Rather, it provides a glimpse at how your voice is perceived at first sight, without knowing anything about you. 

To some extent yes, because there is no need to provide any true private information. Only your username can help identify your voice, but the username doesn't have to disclose who you are. Besides, we recommend not using your full name.

We care about transparency. We do not use personal data for automated decision making, profiling or customizing experience. Besides the calculated averages you can access at any time, there is no more analysis done with your data, nor is it sold to any third party. The model we support for vocal profile testing has already been tested in controlled settings and is already the result of more than five years of academic research.  See the privacy policy for more detailed information.

300ms is in it's Beta version, it means that it is possible the recording doesn't work, or that it isn't properly displayed on devices (for instance, recordings done on Iphones have problems being played on other platforms, this is independent of us). We suggest using another web browser to work around it. If the problem persists, let us know!

For any further inquiry unrelated to technical aspects, please refer to our terms of use and Privacy Policy.

FAQ – The science behind

Here you will find new posts about the science behind voice perception and first impressions, sometimes. 

Accents and prejudice: Why are some accents depreciated and others praised?

  Why are some accents depreciated and others praised? A quick glimpse into the relationship between history, phonetics, and social judgement published in BBC Scotland, …

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Vocal fry

  Vocal fry (or glottalization, pulse phonation, creaky voice) is fascinating. Described by Catford (1977) as “rapid series of taps like a stick being run …

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Cheers! What happens to my voice when I drink…

Soon to come!

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‘That’s not me!’ – Hearing one’s own voice

The dread of the phone call’s sudden echo, or listening to oneself while playing a recording. There are not a lot of people who actually …

Read More →

300ms – values and objectives

1. Inform

 300ms was born after years of academic research on vocal impressions. After being asked so many times how anyone’s voice sound, I have decided to create an entertaining tool to give back to the persons who helped me during my research, and to anyone who might be interested. I will update the science behind section as well as the features of the website along the way. 300ms aims at providing a good grasp of scientific methods, awareness on how to interpret results carefully, and better understanding of theories of non-verbal behavior.

2. Empower

We want you to be the owner of your impressions. Many times now, our personal data is analysed to extract “personality characteristics”, or “soft skills”. Such a thing is very common in recruitment processes. This tool is also a glimpse to how models might process your information during a video interview for example. It doesn’t use any automated analysis itself, but provides a good understanding ground.

3. Apply research to real-world cases

While voice’s market is booming, especially in any human-machine interaction systems, still little is known about how vocal interactions work. 

300ms leverages a model of person perception which proposes new variables to take into account, in order to increase accuracy scores obtained in automated analyses. 

4. Equality

We are all different. Gender differences, personality differences. Interaction is a complex dynamic. Many approaches in the industry still use forward methods when looking for a specific profile. At 300ms we argue that this prevents them from being efficient, and causes damage to the ones that don’t fit the “one size fits all” interaction profile. Any gender, any age, any specificity: it matters.

5. Human-centered approach

Whether AI interacts with human beings or not, using affective variables to better describe the interactions enhances efficiency. We argue towards a human-centered approach to AI, based on affective, and socio-cognitive sciences. 




Driver, J. (2001). A selective review of selective attention research from the past century. British Journal of Psychology92(1), 53-78.

Gray, H. M., Ambady, N., Lowenthal, W. T., & Deldin, P. (2004). P300 as an index of attention to self-relevant stimuli. Journal of experimental social psychology40(2), 216-224.