DEPARTMENT OF PSYCHOLOGY
NEW YORK UNIVERSITY
uncrowded-span model of reading rate — Pelli
et al. (2007) describe a model of reading rate. Levi et al. (2007)
apply it to reading by amblyopes. Here we provide a MATLAB program
that fits the model to human data (e.g. Chung et al., 1998) and plots
a figure. The program is pure MATLAB, compatible
with MATLAB 7 on any computer. (Tested only under Mac OS X.) [Download]
Toolbox — A free software package for vision research. Its routines
provide an efficient interface between a high-level interpreted language
(Matlab) and the display hardware on Macintosh and Windows computers. It
also provides interfaces for timing, sound, and keyboard. The number
of Psychtoolbox installations (with unique internet addresses) was 4,598
in December 2007. (See the overview for
the current count.) Of these, 1634 are running under Mac OSX, 2958 under
Windows and 6 under Linux. (We estimate that a further several hundred
computers are still running the Mac OS 9 version of the Psychtoolbox.)
The Psychtoolbox forum averages
more than 3 messages a day. We know of 126 grant-supported
projects that use it. And 404 papers cite it.
(With David Brainard, Allen Ingling, and Mario Kleiner.)
- Chung, S. T. L., Mansfield, J. S.,
Legge, G. E. (1998). Psychophysics of reading. XVIII. The effect of
print size on reading speed in normal peripheral vision. Vision
Research, 38, 2949–2962.
- Levi, D. M., Song, S., & Pelli,
D. G. (2007) Amblyopic reading is crowded. Journal of Vision, 7(2):21,
- Pelli, D. G., Tillman, K. A.,
Freeman, J., Su, M., Berger, T. D., & Majaj, N. J. (2007) Crowding
and eccentricity determine reading rate. Journal of Vision, 7(2):20,
Quest — A
free software package for threshold estimation. It will run on any computer
with MATLAB 5 or better. It is distributed both on its own and as part
of the Psychophysics Toolbox (above). It's easy to use, has a sound theoretical
footing, and is robust. We use it for all our work and recommend it without
reservation. It's quite popular. You can download it as a stuffit or zip archive.
A. B. & Pelli, D. G. (1983) QUEST: a Bayesian adaptive psychometric
method. Percept Psychophys, 33 (2), 113-20. 297
VideoToolbox — A
free collection of two hundred C subroutines for Macintosh computers
to calibrate and control the computer-display interface, making it possible
to create accurately specified visual stimuli. This became the foundation
for the Psychophysics Toolbox.
||Pelli, D. G. (1997) The VideoToolbox software for
visual psychophysics: transforming numbers into movies. Spatial
Vision, 10, 437-42. [full
||Pelli, D. G., & Zhang, L. (1991)
Accurate control of contrast on microcomputer displays. Vision
Research 31, 1337-1350. 224
Tips — Advice
for users of the Psychtoolbox and VideoToolbox.
|| Pelli, D. G. (1997) Pixel independence: measuring
spatial interactions on a CRT display. Spatial Vision, 10,
Sloan font — Based on Louise Sloan’s
design, which has been designated the US standard for acuity testing
by the National Academy of Sciences, National Research Council, Committee
on Vision (1980, Adv Ophthalmol, 41, 103-148. [PubMed]).
Note that the standard specifies only CDHKNORSVZ, whereas the font file
goes beyond that to provide a complete uppercase alphabet A-Z in a consistent
style. The C is a Landolt C. The C and O are particularly hard to discriminate
from each other, so some studies may wish to omit the C (see Elliott,
Whitaker, & Bonette,
1990. Ophthalmic Physiol Opt, 10(4), 323-326. [PubMed]).
This font was developed for the Pelli-Robson Contrast Sensitivity Chart.
It is made available here for research purposes and may not be distributed
further. Commercial use of this font would require a license from Denis
Pelli. To download, choose version 1 or 2, as explained in the text document
Version 1: Sloan for
Macintosh (zip or stuffit archive)
or Windows (zip archive). This
is a PostScript Type 1 font, which you install like any other font.
2: Sloan.otf is in the new universal Open
Type font format, which is supported by more and more applications on Mac
and Windows platforms.
Adobe provides installation
instructions. Publications of research using any of these font files
font — 26 Chinese characters a-z based on high-resolution scans
of Yung Chih-sheng’s beautiful calligraphy in a beginning Chinese
primer (DeFrancis, J., 1976, Character Text for Beginning Chinese, Second
Ed. New Haven, CT: Yale University Press.). To download, choose a format: Yung
for Macintosh (zip or stuffit archive)
or Windows (zip archive). This is
a PostScript Type 1 font, which you install like any other font. Adobe
instructions. Publications of research using this font should cite:
|| Pelli, D. G., Robson,
J. G., & Wilkins, A. J. (1988) The design of a new letter chart
for measuring contrast sensitivity. Clinical Vision Sciences
2, 187-199. 287
||Pelli, D. G., Burns, C. W., Farell, B., & Moore-Page,
D. C. (2006) Detecting features and identifying letters. Vision
Research, 46(28), 4646-4674. [PubMed]
Toolbox is a set of MATLAB functions providing communication
with a particular USB data acquisition device (daq): the PMD-1208FS made
by Measurement Computing. This daq costs $150 and offers "50
kHz" input and output 12-bit sampling of analog voltages (8
in, 2 out) and 16 digital i/o lines, with signals brought out to
screw terminals. ("50 kHz" is a theoretical upper limit:
as of 18 April 2005 we attain 2 kHz.) The PMD-1208FS is the size
of a wallet and is powered through its USB cable. We have complete
control of it from within MATLAB, via the PsychHID extension. The
Daq Toolbox is free and can be downloaded from the Daq
Toolbox web page. It is self-contained, and may be used with
or without the rest of the Psychtoolbox. The only requirements are
MATLAB, Mac OS X 10.3 or better, and a USB port to connect the PMD-1208FS.
AutoBrightness.applescript and AutoBrightness.m (click to download) allow you to turn off a pesky feature of Apple's liquid crystal displays. In Mac OS X, this feature is manually enabled/disabled by the "Automatically adjust brightness" checkbox in the System Preferences: Displays panel. While the feature is enabled, your Mac slowly adjusts the screen luminance of your Apple liquid crystal display, to track the luminance of the room. That's bad for screen calibration and perhaps also bad for your experiments. My AutoBrightness routines allow your programs to read the on/off setting of that feature, and enable or disable it. The Applescript will work from any application (e.g. MATLAB, Mathematica) that can send it to the Mac OS. The MATLAB routine merely calls the Applescript, and can easily be translated to any suitable language. For use in MATLAB, just put both files anywhere in MATLAB's path. I hope they will be added to the Psychtoolbox.
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