Zimmerman Trial: Judge Excludes Voice Experts
Posted on Sat Jun 22, 2013 at 02:43:43 PM EST
Tags: George Zimmerman, Trayvon Martin (all tags)
Judge Debra Nelson has issued her order on the admissibility of the testimony of the state's proposed voice/speaker identification experts: They will not be allowed to testify. The experts, Tom Owen and Alan Reich, had claimed to be able to analyze the cries for help in the background of a witness' 911 call.
The order is here. It is very easy to read and understand. Shorter version: The techniques and methodologies used by Owen and Reich to determine who was or was not crying out in the background of the call are new and novel, are not generally accepted in the scientific community, and are unreliable and backed only by Owen and Reich, each of whom have a personal stake in the acceptance of their opinions. In addition, Reich's testimony is likely to confuse the issues and mislead the jury. [More...]
Quotes from the opinion:
"The purpose of Frye is to ensure the reliability of expert testimony."
...The scientific methodologies and techniques used by Mr. Owen and Dr. Reich are not reliable as they are not sufficiently established and not generally accepted in the scientific community.
...The proponent of opinion testimony that espouses new or novel scientific theories bears the burden of establishing by a preponderance of the evidence the general acceptance of the underlying scientific principles and methodology. The State failed to carry its burden.
Some of the reasons for the finding:
Although the aural perception and spectral analysis are not new or novel, their application by the State's witnesses to the samples from the 911 call in this case is a scientific technique that is new and novel. There is no competent evidence that the scientific techniques used by Mr. Owen and Dr. Reich are generally accepted in the scientific field. There is no evidence to establish that their scientific techniques have been tested and found reliable.
...Both Mr. Owen and Dr. Reich testified in support of their own technologies and techniques. They have an interest in the outcome of this issue because it is their methodologies being tested. Mr. Owen acknowledged that he markets and owns a small financial interest in the software program he utilized as a basis for his opinion.
On relevancy and likelihood of confusion:
§90.403, Fla. Stat. (2013) provides in pertinent part, "Relevant evidence is inadmissible if its probative value is substantially outweighed by the danger of unfair prejudice, confusion of issues, misleading the jury, or needless presentation of cumulative evidence."
...The Court finds that Dr. Reich's testimony regarding the amplified tapes would confuse issues, mislead the jury and, therefore, should be excluded from trial.
On Reich, the Court referred to the lack of any kind of blind testing. In a blind test, the expert would not know the facts of the case or the "listener bias" , where a listener with a biased outlook, often due to knowledge of the underlying facts, makes conclusions to support his or her preconceived notions. It was hypothesized that Dr. Reich, who took up the case based upon personal interest, subconsciously wanted to hear identifiable words. The Court finds that Dr. Reich's testimony regarding the amplified tapes would confuse issues, mislead the jury and, therefore, should be excluded from trial.
The order also deals a blow to biometric voice analysis in general:
The Court finds and concludes that aural perception and spectral analysis have been widely used for many years and are sufficiently established to have gained general acceptance within the scientific community. While biometric analysis has been available for several years, it is not as widely accepted at this time.
I was glad to see the order refer to the lack of blind testing. The Judge says of the defense experts, she found Dr. French most credible. She quotes him as stating:
He testified that Dr. Reich's opinions were affected by his prior knowledge of the facts of this case. As those in the field of forensic speech analysis must always be cognizant of this risk, he prefers to conduct blind analyses where he does not know the facts of the case.
She also notes that French testified that "one cannot tell the age of a speaker based upon the sound of his voice.
She cites all of four of the defense experts who emphatically stated a scream cannot be compared to spoken words. Specifically referring to French, she writes:
He explained that screaming under the type of stress present in this case changes the voice in an unpredictable manner and cannot be replicated in laboratory conditions. Moreover, without distinct words there are no characteristics that lend themselves to comparison. A forensic expert cannot hear the variables used with aural comparison in screams, including the pronunciation of certain phonemes, accents, speech rate, and pitch variations.
What the ruling means for the trial: The state can call witnesses who are familiar with the voices of George Zimmerman and Trayvon Martin to give an opinion as to who is speaking. The matter is then left to the jury to decide.
I started writing about the voice/speaker identification issues and Owen's EZ Voice software here. After reading Reich's report and the report of another proposed state expert whom it decided not to call a the Frye hearings, I wrote:
The jurors can listen to the tape and decide for themselves if it was Zimmerman on the tape. Lay witnesses who are familiar with Zimmerman and Martin's voice can probably give their opinion. The first state report is equivocal and a guesstimate. The second is a joke. The court should exclude these expert reports.
During the Frye Hearing, I opined that Owen's analysis should not be admitted under Frye or Daubert.
The methodology is skewed because he is comparing a scream to spoken words, there's too much background noise, the environmental and recording conditions were too different, the scream samples aren't long enough, the quantity of words for comparison is insufficient, there are pitch issues because the screamer was under emotional stress, etc. He can't even give an opinion beyond "probable" in his words that it was not Zimmerman screaming.
As to his biometric program, he shouldn't be the one to opine on whether it's accepted in the scientific community because he is the proprietor of the software and has made a career out of the reliability of spectrography. In other words, he's biased.
...The jury ...can listen to the 911 call and decide for themselves who they think is crying out for help. They don't need "expert" testimony and they certainly don't need unreliable, speculative, discredited conclusions.
The judge, in more polite language, agreed.
Also see the discussions on our George Zimmerman forums on Voice ID experts, the June 7 Frye hearing, the June 8 Frye Hearing, the June 17 Frye Hearing and the June 20 Frye Hearing and on Who is Screaming on the 911 call.
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