identification task...negative d' values. (silvadmr )


Subject: identification task...negative d' values.
From:    silvadmr  <silvadmr@xxxxxxxx>
Date:    Tue, 2 May 2006 14:22:06 -0300

--_=__=_XaM3_.1146590526.2A.91175.42.9937.52.42.007.846119401 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Dear list, I have some few small negative values of d' obtained from an identificati= on task in witch subjects label vowel sounds from a continuum with tree p= honeme labels. Generally, the graphs and tables in the literature never s= how negative values of d' ( i think it occurs here and there). The interpretation of such values from an identification task of that kin= d must not be the same as the interpretation of negative values obtained = in a yes-no experiment...cause in the case of indentification we have "di= fferent sounds" rather then a "signal stimulus" and a "signal plus noise = stimulus". What is the usually adopted procedure? Should I take the absolute values (given the nature of the identification= task)?...should I convert them to 0? should I keep them as negative valu= es? Thanks! --_=__=_XaM3_.1146590526.2A.91175.42.9937.52.42.007.846119401 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable <DIV style=3D"FONT-SIZE: 12px; FONT-FAMILY: verdana, arial"> <DIV>Dear list, <DIV>&nbsp;</DIV> <DIV>I have some few&nbsp;small negative values of d'&nbsp;obtained from&= nbsp;an identification task in witch subjects&nbsp;label vowel sounds fro= m a continuum&nbsp;with tree&nbsp;phoneme labels. Generally, the graphs a= nd tables&nbsp;in the literature never show&nbsp;negative values of d' ( = i think it&nbsp; occurs here and there).</DIV> <DIV>The interpretation of such values from an identification task of tha= t kind must not be the same as the interpretation of negative values obta= ined in a yes-no experiment...cause in the case of indentification we hav= e "different sounds" rather then a "signal stimulus"&nbsp;and a "signal p= lus noise&nbsp;stimulus".</DIV> <DIV>&nbsp;</DIV> <DIV>What is the usually adopted procedure?</DIV> <DIV>Should I take the absolute values (given the nature of the identific= ation task)?...should&nbsp;I convert them to 0? should&nbsp;I keep them a= s negative values?</DIV> <DIV>&nbsp;</DIV> <DIV>Thanks!</DIV></DIV></DIV> --_=__=_XaM3_.1146590526.2A.91175.42.9937.52.42.007.846119401--


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