George Zimmerman and Trayvon Martin: Judge orders voice testimony to be excluded

23 June 2013

The Zimmerman ruling

A ruling has been handed down on the voice evidence in the Zimmerman case we have been following. Judge Debra S Nelson gave high praise for Prof Peter French’s evidence (in her words, ‘The Court found the testimony of Dr. French to be the most compelling of the witnesses presented.‘). That is an important endorsement for the role of genuine expertise in relevant branches of phonetics in the legal system.>>   Read the rest now

George Zimmerman and Trayvon Martin: Can the voice evidence identify the speaker?

12 June 2013

An ongoing murder case in Florida, USA is discussing the vexed issue of whether it is possible to identify a speaker from a tiny, barely intelligible ‘grab’ of poor quality audio. One of the issues is the extent to which speaker comparison depends on prior decisions about what is being said (i.e. forensic transcription). The USA is very open about their court proceedings, so we are able to follow along with the debate. In this post you can hear the audio, and then (preferably in that order) read about case and listen to the expert testimony.>>   Read the rest now

The crisis call experiment

Watch the video here (if you haven’t already)

Hear the full audio here (warning: potentially distressing)

Quick summary here:

More detail here:

Current law allows police transcripts to assist juries in understanding the content of indistinct forensic audio – with a number of legal safeguards intended to mitigate any risk that an inaccurate transcript might mislead the jury. The problem is that the safeguards rely on lawyers and judges gaining a sense of personal confidence that they hear words suggested by the transcript. The present article describes a new experiment showing that personal confidence is a poor indicator of perceptual accuracy, since listeners can be easily and unwittingly “primed” to hear words suggested by an inaccurate transcript. This confirms previous research suggesting current safeguards are inadequate, adds new findings regarding the effect of an alternative suggestion, and supports the need for an evidence-based process ensuring all indistinct forensic audio used in court is accompanied by a reliable transcript. It also indicates there is an urgent need to change legal procedures for admission of transcripts of indistinct forensic audio used as evidence in criminal trials.>>   Read the rest now