Witnesses’/Victim’s Recognition of Once-Heard Voices g Professor Ray Bull, Forensic Psychology, University of Leicester, UK Paper presented at the Second Pan Paper presented at the Second Pan- - American/Iberian Meeting on Acoustics American/Iberian Meeting on Acoustics Organised by the Acoustical Society of Organised by the Acoustical Society of g g y y y y America America Cancun, Mexico November 2010 Cancun, Mexico November 2010 3aSC8 Special Session on Forensic Voice Comparison and Forensic Acoustics @ 2nd Pan-American/Iberian Meeting on Acoustics, Cancún, México, 15–19 November, 2010 http://cancun2010.forensic-voice-comparison.net
1. In 1974 in response to media focus on some criminal cases In 1974 in response to media focus on some criminal cases involving what turned out to be false convictions based on involving what turned out to be false convictions based on mistaken witness testimony, the Government in England mistaken witness testimony, the Government in England and Wales set up an official Committee of Inquiry that and Wales set up an official Committee of Inquiry that d W l d W l t t ffi i l C ffi i l C itt itt f I f I i i th t th t sought to better understand how honest witnesses can sought to better understand how honest witnesses can sometimes give incorrect testimony in court This sometimes give incorrect testimony in court This sometimes give incorrect testimony in court. This sometimes give incorrect testimony in court. This Committee was chaired by Lord Devlin and its report was Committee was chaired by Lord Devlin and its report was published in 1976. published in 1976.
2 In In the the early early 1980 1980s s I I conducted conducted (with (with Brian Brian Clifford) Clifford) for for the the Government Government a programme Government Government a programme programme of programme of of research of research research studies research studies studies that studies that that was that was was was given given an an impetus impetus by by the the 1976 1976 publication publication of of this this ‘Devlin ‘Devlin Report’. Report’ p . The The Report Report stated stated that that as as far far as as the the Committee Committee members members were were concerned no concerned no research research had had been been conducted conducted on on voice voice identification identification (i (i. .e e. . human human recognition recognition of of a voice voice heard heard only only once once before) before) but but that that “research “research should should proceed proceed as as rapidly rapidly as as possible possible into ibl i t ibl into the i t th the practicality th practicality of ti ti lit lit of voice f voice parades i parades ... d ... or or any any other other appropriate appropriate methods” methods”. .
3 In In a a 1984 1984 book book chapter chapter in in which which we we reviewed reviewed our our research research studies (and studies studies (and studies (and those (and those those of those of of others) of others) others) we others) we we concluded we concluded concluded that concluded that that that “Until “Until future, future, more more realistic realistic studies studies argue argue to to the the contrary contrary we we would recommend would recommend that that prosecutions prosecutions based p based solely solely on y on a witness’ identification witness’ identification of of a a suspect’s suspect’s voice voice (if (if the the suspect suspect is is a a stranger) stranger) ought ought not not to to proceed, proceed, or or if if they they do do proceed proceed they they should they they should should fail should fail fail fail. We We We say We say say this say this this because this because because because …. we we are we we are are of are of of the of the the the opinion opinion that that ear ear- -witnessing witnessing and and eye eye- -witnessing witnessing are are similarly similarly and and considerably considerably error error prone prone. . This This is is not not to to say say that voice that h voice identification i id id identification should ifi ifi i i should not h h ld ld not be b be used used as d as an an aid aid to id id to the the h prosecution prosecution or or the the defence, defence, but but it it should should not not form form any any major part major major part major part of part of of the of the the evidence the evidence evidence presented evidence presented presented in presented in in court in court court.” court.
4 Five years Five years later, later, in in 1989 1989, an an overview overview on on ear ear- - witness witness identification it it identification id id tifi tifi ti ti ( ( (written (written by itt itt b by five fi fi five respected respected North North American American psychologists psychologists – – D ff D ff Deffenbacher Deffenbacher et b b h h et al t al.) was l ) was published published that bli h d bli h d th t th t that examined all examined all the the published published research research on on the the accuracy accuracy with with i h i h which which hi h hi h people people l (i (i (in (in experiments) experiments) are are able able correctly correctly to to identify identify a a voice they voice i they heard h heard once h h d d once previously previously. i i l l . In I In their their h i h i concluding concluding paragraph paragraph they they stated stated that that
5 “Inasmuch “Inasmuch as as the the results results we we have have reported reported are are optimal optimal in in that that witnesses were witnesses witnesses were witnesses were not were not not stressed not stressed stressed and stressed and and there and there there was there was was no was no no attempt no attempt attempt at attempt at at at voice voice disguise, disguise, recognition recognition accuracy accuracy at at realistic realistic delays delays and and speech speech sample sample durations durations was was so so low low that that we we would would agree agree with with Bull ith ith B ll B ll and Bull and and Clifford’s and Clifford’s Clifford’s (1984 Clifford’s (1984 1984) conclusions 1984) concl sions concl sions conclusions. Depending Depending Depending Depending on on the the parameters parameters involved, involved, recognition recognition of of an an unfamiliar unfamiliar voice voice may may have y have a a sufficient sufficient probability probability of p p y y of accuracy accuracy that y that it it could could be be of of use use in in a a police police investigation investigation. . Unless Unless further further more ecologically more ecologically valid valid studies studies argue argue to to the the contrary, contrary, however, ear however, however ear however ear-witnessing ear-witnessing witnessing is witnessing is is so is so so error so error error prone error prone prone as prone as as to as to to suggest to suggest suggest that suggest that that that no no case case should should be be prosecuted prosecuted solely solely on on identification identification evidence evidence involving involving an an unfamiliar unfamiliar voice voice. .” ”
6 A later later overview overview of of research research on on voice voice identification identification was was published in published published in published in 1995 in 1995 1995. In 1995. In In that In that that chapter that chapter chapter a Canadian chapter a Canadian Canadian professor Canadian professor professor of professor of of of psychology psychology (Dan (Dan Yarmey) Yarmey) reviewed reviewed not not only only 12 12 publications publications of of his his own own but but also also some some 22 22 publications publications by by other people other other other people people on people on on the on the the topic the topic topic of topic of of of voice voice identification oice oice identification identification identification. This This This This overview overview stated stated that that “One “One of of the the myths myths still still held held by by many many laypersons laypersons and yp yp and officials officials in in the the criminal criminal justice justice system j system is y is the the belief belief that that eyewitness eyewitness memory, memory, including including voice voice recognition, recognition, is is merely merely common common knowledge” knowledge” and and that that “Most “Most voice voice identification voice identification voice identification issues identification issues issues of issues of of concern of concern concern to concern to to the to the the court, the court court, of court of of of course, course, are are for for voices voices of of strangers strangers… …identification identification for for unfamiliar unfamiliar voices voices must must by by treated treated with with caution” caution”. .
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