Scientists sound boring! Quantifying the 'monotone'

I read a blog post by Alan Mars last week about the excellent Material World science programme on BBC Radio 4, complaining about how all of the scientists interviewed on the show had such boring voices. Alan says,

"Sadly most of the interviewees speak within a very narrow band of auditory frequencies. Monotone in common parlance. It sounds as if the scientists vocal "loudspeakers" are turned in toward their body, rather than outwards towards a public that is thirsty for the latest news."

It doesn't help my scientific colleagues that the show's host, Quentin Cooper (hard at work in the studio, left, picture by bowbrick on Flickr), speaks in such an animated and engaging way.

Listening to the Material World podcast with Alan's quote in mind, the contrast between Quentin's delivery and that of the scientists was unmistakable. The differences become even more stark after a frequency analysis with Audacity.

The vertical axes in these plots are the pitch of the speaker's voice, and the horizontal axes time. The plots were produced using Audacity's EAC autocorrelation function to extract the pitch of the voice. I won't tell you which episode this is!


Here is Quentin (the host), introducing a show:

 

and here's the (male) scientist on immediately after:

The 'monotone' is striking!

Here's another bit of Quentin (this time as a Fourier transform frequency/time plot):

 

and here's the (female) scientist on next:

Flat as a pancake - it's not just the men who have a problem!

When we're training new lecturers, "don't speak in a monotone" is one of the first pieces of advice, followed by the trainer demonstrating a comedic robot-like example of a monotone speaker. However, it's clear that even when a scientist is putting their best foot forward (presumably, since they're on national radio!), they are clearly still speaking in a relatively monotonic voice compared to radio-trained voices.

I'm convinced that a bit of variation in speaking pitch and volume is one of the main factors which determines whether students perceive a lecture as boring or interesting, not necessarily what you're actually saying!