ANCHOR Project Page

The work in category rating and absolute identification complements my research on perceptual learning. The combination of quantitative experimentation and formal modeling proved fruitful in this domain as well. A Psychological Review article (Petrov & Anderson, 2005) consolidated the scattered literature on direct psychophysical scaling and exposed the intimate relationship between direct scaling and associative memory. A series of studies revealed that human response distributions are markedly non-stationary and non-uniform even when the stimulus distributions are stationary and uniform. Moreover, skewed stimulus distributions induce context effects in opposite directions depending on the presence or absence of feedback. A memory-based model called ANCHOR accounts for these and many other dynamic effects.

Publications

A comprehensive list is available from the publication page. The defining articles are:

Petrov, A. & Anderson, J. R. (2005)

The Dynamics of Scaling: A Memory-Based Anchor Model of Category Rating and Absolute Identification. Psychological Review, 112(2), 383-416.
Abstract Reprint (pdf)

Petrov, A. (2011)

Category rating is based on prototypes and not instances: Evidence from feedback-dependent context effects. Journal of Experimental Psychology: Human Perception and Performance, 37 (2), 336-356.
Abstract Reprint (pdf) Data

Data Sets

The data sets for Petrov (2011) are available in full. The same archive contains the Matlab implementation of INST (the instance-based variant of ANCHOR).
The data for Petrov & Anderson (2005) are available from Alex Petrov upon request.

Software

anchor-v2.2.zip ReadMe Contents License

The complete Matlab implementation of the ANCHOR Model is available from my open-source software page under the GNU General Public License.