BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Similarity Judgements in Visual\, Auditory and Audio-visual Stimul
 i - Michelle To (University of Cambridge)
DTSTART:20091022T120000Z
DTEND:20091022T130000Z
UID:TALK20976@talks.cam.ac.uk
CONTACT:Dr James Kirkbride
DESCRIPTION:Our sensory neurons provide measurements of objects\, allowing
  us to categorise them or judge their similarity\, but the sensory respons
 es based on these measurements are variable\, partly due to neuronal noise
 . A simple probabilistic classifier for such situations assumes that objec
 t likelihoods are Gaussian probability distributions and predicts Euclidea
 n summation of cues in similarity judgments.  However\, our psychophysical
  experiments show that similarity judgments to transformed natural visual 
 and auditory stimuli deviates systematically from Euclidean summation.  Na
 tural stimuli which differ from an original in two ways are judged slightl
 y less different than Euclidean summation of the two difference cues would
  predict.  This modification of the optimal classifier may be a consequenc
 e of the neural events being correlated.  Our findings are consistent with
  a Bayesian classification system that assumes a small correlation (r = 0.
 12-0.19) between sensory messages. This provides an important link between
  low level neurophysiology and high level cognitive performance.
LOCATION:Entertaining Room\, Darwin College
END:VEVENT
END:VCALENDAR