Alternating block task results for ferret 1.

<p>A) A psychometric function measured over 6 sessions (dots), expressed as a function of attenuation. Attenuations corresponding to the easy and hard signal levels are marked as blue and pink discs, respectively, and grey verticals. The dashed line corresponds to chance performance. B) Mean outcome of a trial conditional upon its position within an odd or even block of 24 trials. Trials separated by 48 positions are analysed together. Easy trials comprise the odd blocks (blue), hard trials the even blocks (pink). Rows: 1. probability of a correct response; 2. probability of a hit; 3. probability of a false alarm; 4. probability of a positive response. Error bars show s.e.m. C) Mean outcome of a trial as a function of its position in an odd or even block of 8 trials. Trials separated by 16 positions are analysed together. Exponential fits to the data are shown as thick green and magenta curves (see body text). D) Hit and false alarm probabilities from the 8-trial block data (panel C, rows 2 and 3) plotted in ROC space. The fine dotted line is a trajectory linking neighbouring positions, including 16 back to 1. The dashed line corresponds to chance performance. Markers are filled according as they represent as easy (blue) or (hard) trials. The markers corresponding to the mean outcome of the first trial in an easy or hard block are especially highlighted, using “1” or “9”, respectively.