Signal detection theory

[Tobias]

They don not only have higher hit rates but also the same false alarm
rate. So they are not more often saying "yes" in blank trials but only
in target trials.
If they really had a bias shouldn't they also have a higher false
alarm rate?

On 21 Apr., 01:55, Robert Ariel <rar... at kent.edu> wrote:
> Well, if you buy the assumptions of SDT you can.  Remember, SDT makes
> assumption about behavior.  Specifically that decisions are made by applying
> a decision criterion to the evidence extracted from each trial.   So, you
> could conclude that one condition has a higher hit rate because that
> condition has a larger bias toward saying yes in your experiment.  I guess
> the question is, does it make theoretical sense to do so?
>
>
>
> On Mon, Apr 19, 2010 at 7:33 AM, Tobias <tobias... at gmail.com> wrote:
> > Thanks Robert,
>
> > if I am not getting you wrong, this means that C is independent of d'
> > but not of the hit rate.
> > The question occurs to me if you can really say that one condition is
> > more liberal if they are just better obviously.
>
> > Cheers,
> > Tobias
>
> > On 16 Apr., 21:25, Robert Ariel <rar... at kent.edu> wrote:
> > > Tobias,
>
> > > Computationally, C is the average of the your transformed hit and false
> > > alarm rates.  You can see this in the equation you presented.  So, no
> > doubt
> > > if you have equal false alarm rates across conditions, differences in C
> > are
> > > resulting because of differences in hit rates.
>
> > > Basically with equal false alarm rates, the condition with a higher hit
> > rate
> > > will always be more liberal.  If hit rates are equal, the condition with
> > > higher false alarm rate will be more liberal.
>
> > > Best,
>
> > > Robert
>
> > > On Fri, Apr 16, 2010 at 9:59 AM, Tobias <tobias... at gmail.com> wrote:
> > > > Hi together,
>
> > > > this might be a bit off topic but as you are all very much into
> > > > psychological experimental science you might be of great help for this
> > > > issue. Besides, my topic is the outcome of an E-Prime experiment ;)
>
> > > > It is about the response bias in signal detection theory (SDT). I've
> > > > heard that C is usually better than Beta as a measure of response bias
> > > > as it is indpendent of d'. Now what I have in my experiment is a very
> > > > high hit rate for condition A and a lower hit rate for condition B.
> > > > False alarm rates are however the same for A and B. So what I get
> > > > using the formula for C (C = -0.5*(z(false alarms) + z(hits)) is a
> > > > liberal criterion C for A and a less liberal criterion for B.
>
> > > > So can I actually say that A is more liberal? Apparently this is only
> > > > due to the fact that the hit rate is higher. I am quite puzzled by
> > > > this... glad for any help!
>
> > > > Tobias
>
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