These experiments require a Java Version 5 Virtual Machine. Download and install the Java Runtime Environment Plugin if the respective message appears in the buttons below.
Some of the experiments try to show the resulting data files in a popup window after the experiment has been finished. In order to see them you have to enable your browser to show popup windows from this site. You need not do this if you do not want to see the data files.
This is a demonstration which
combines stimulus object composition and
adjustable stimulus parameters. It shows two Müller-Lyer objects. The
one on top is the standard and the one on the bottom is an adjustable
line only. Adjustment is done with the curosr left/right keys and
finished adjustment is indicated with the 'End'-key.
This shows adaptive stimulus control as it is used in psychophysical
experiments. The design file implements a
simple 1-down-1-up-procedure (Levitt, 1971) to find a vertical line which appears to
be of the same length as a given horizontal line. The experiment is
described in Chapter 3 of Irtel (1991) and is similar to a study by
Künnapas, T. M. (1955). An analysis of the "vertical-horizontal illusion". Journal of Experimental Psychology, 49, 134-140.
Levitt, H. (1971). Transformed up-down methods in psychoacoustics. The Journal of the Acoustical Society of America, 49, 467-476.
This design file presents
sinusoidal gratings at various spatial frequencies, amplitudes, and
orientations. It shows a complete implementation of the ModelFest
stimuli. Note that because of the rather large amplitudes used
here for demonstration purposes the nonlinear gamma function of your
monitor might make the sinusoids appear to be non-symmetric. This will
not be the case when near-threshold amplitudes are used.
The second version of this demo shows static images of the same
stimuli. A detailed description of the stimuli may be found at
Here is another gabor pattern demonstration
which includes colors and motion.
A simple sound
discrimination task which sends data to an E-Mail
adress given as an input argument.
This demonstration experiment contains a test for color blindness
similar to that suggested by Anstis et al. (1986). It sends its data
to an E-Mail address which has to be entered before the experiment
starts. The design file is color_vision_test.pxd.
Anstis, S. M., MacLeod, D. A., Cavanagh, P., Lewis, T., Maurer, D., Mather, G. (1986). Computer-generated screening test for colorblindness. Color Research and Application, 11, 63.
This experiment shows adjustment of the
luminance of a color stimulus combined with animation. It runs flicker
photometry to match the flicker-brightness of two color stimuli.
Wyszecki, G. & Stiles, W. S. (1982). Color science (2nd ed.). Ney York: Wiley.
This experiment shows adjustment
of a color in 3 dimensions. Adjustment coordinates are the
LCh-coordinates of CIELab space. Moving the mouse pointer left/right
with the left button down moves the color along the hue circle. Moving
the mouse pointer up/down with the left button down increases or
decreases the Lightness value. The same moouse motion with the right
button down increases or decreases the Chroma coordinate.
The following series of experiments present a sample of colors and allow selection of a single color patch.
This example allows
for selection of a single color from an arbitrary sample.
The next example is similar, but here the
color sample is a constant Lightness plane of the CIELab color
space. In this case the subject also can navigate through CIELab space.
The 3rd example of this series uses a
color sample which is the highest Chroma boundary of the Munsell
Book of Colors which can be shown on a computer monitor.
The color_transforms.pxd design file
can be used to test PXLab's color transformations.
Her is an apparent motion demonstration which presents Wertheimer's
apparently moving bar.
Pulfrich, C. (1911). Stereoskopisches Sehen und Messen. Jena: Fischer.
Pulfrich C. (1922). Die Stereoskopie im Dienst der isochromen und heterochromen Photometrie. Naturwissenschaften 10, 553-564, 569-574, 596-601, 714-722, 735-743 und 751-761.
This shows a left or right arrow and expects a left or right cursor
key response. This design file is a short
version of an experiment descibed in Chapter 1 of Irtel (1991).
Irtel, H. (1991). Experimentalpsychologisches Praktikum. Heidelberg: Springer.
This shows a list of text items which may be ranked by the
Shows a white ring as a target signal for response time
measurement. The ring is preceded by a white dot in its center. The
dot precedes the ring by a varying amount of time (20 to 100 ms). This
procedure is similar to that of Werner (1935) and Fehrer and Raab
(1962). The subject will not perceive the dot but the response times
will show that the dot acts as the response signal. The design file defines 15 trials.
Werner, H. (1935). Studies on contour: I. Qualitative analyses. American Journal of Psychology, 47, 40-64.
Fehrer, E. & Raab, D. (1962). Reaction time to stimuli masked by metacontrast. Journal of Experimental Psychology, 63, 143-147.
This experiment has been
created during an on-line presentation at the "Lehr-Lern-Workshop
Allgemeine Psychologie" at University of Graz, November 19, 2004. It
demonstrates target letter search in a set of distractors.
This experiment replicates the Stroop experiment of Chapter 7 in
Irtel (1991). It is a non-vocal version of the classical Stroop (1935)
task. The number of trials in this design file has been reduced to 12.
Note that PXLab also is able to run the vocal Stroop task by using its built in voice key response mechanism.
Irtel, H. (1991). Experimentalpsychologisches Praktikum. Heidelberg: Springer.
Stroop, J. R. (1935). Studies of interference in serial verbal reactions. Journal of Experimental Psychology, 18, 643--661.
This experiment demonstrates
blindness to stimulus changes across flicker
breaks. It is identical in procedure to Experiment 1 of
Rensink et al. (1997).
Rensink, R.A., O’Regan, J.K., & Clark, J.J. (1997). To See or Not to See: The Need for Attention to Perceive Changes in Scenes. Psychological Science, 8, 368-373.
This is a word recognition task with pseudohomophones. It
replicates a practical experiment of the
University of Nottingham
School of Psychology based on Underwood et al (1988).
Underwood, G., Roberts, M.J., & Thomason, H. (1988). Strategical invariance in lexical access: The reappearance of the pseudohomophone effect. Canadian Journal of Psychology, 42, 24-34.
This experiment first shows
black/white and color pictures in a learning list and then runs a recognition memory test
with pictures masked by appropriate masking images. It replicates an
experiment by Gegenfurtner & Rieger (2000). The SOA between picture
and mask is 100 ms.
Gegenfurtner, K.R. & Rieger, J. (2000) Sensory and cognitive contributions of color to the perception of natural scenes. Current Biology, 10, 805-808.
The file sam.pxd shows several
Self-Assessment-Manikin scales (Lang, 1980) combined with text,
color and image objects. Scale variants are: 5, 7, and 9 point
scales. The 9-point scale my be shown in a reduced form using only 5
images and seperate selection dots. The valence scale my be shown in
full body or portrait mode. All images are scalable and can be fit
to any size.
The screen shots on the PXLab Self-Assessment-Manikin Scales page also show what can be done with the PXLab SAM tool.
Lang, P. J. (1980). Behavioral treatment and bio-behavioral assessment: computer applications. In J. B. Sidowski, J. H. Johnson, & T. A. Williams (Eds.), Technology in mental health care delivery systems (pp. 119-l37). Norwood, NJ: Ablex.
shows the 10 item version of the Big Five Inventory developed by
Rammstedt & John (2007). The trial data contain the item ratings and
the block data contain the scale values for the 5 scales.
Rammstedt, Beatrice & John, Oliver P. (2007). Measuring personality in one minute or less: A 10-item short version of the Big Five Inventory in English and German. Journal of Research in Personality, 41, 203-212.
Not a full IAT but a design file which shows how it can be
done. This demo is a replication of a demo which may be found at http://implicit.harvard.edu. They
call it the 'Age IAT'. This design file is written such that it is
easy to plug in all kind of IAT-stories.
Greenwald, A. G., Nosek, B. A., & Banaji, M. R. (2003). Understanding and Using the Implicit Association Test: I. An Improved Scoring Algorithm. Journal of Personality and Social Psychology, 85, 197-216.
Nosek, B. A., Greenwald, A. G., & Banaji, M. R. (2005). Understanding and using the Implicit Association Test: II. Method variables and construct validity. Personality and Social Psychology Bulletin, 31, 166-180.
This design file is a demonstration of
what can be done with PXLab's expression language. It shows trials of
the well known Monty Hall
dilemma. All rules and restrictions of the game are expressed using
PXLab's expression language syntax applied to the parameters of proper
Here is another link to start the program. This link uses a command
line argument to tell the design file that its internal game
parameters should be shown to the subject.
The following design file runs a slide
show of images from the net.
The same design file can be used to run the program with its display being embedded into an applet frame. This works for all PXLab experiments which can be run as applets.
The following image example
allows selection of a single image from a matrix of images.
The next example shows an
image and collects a rating scale response. The rating scale contains
an adjustable pointer and the final adjustment is signaled by pressing
the space bar.
PXLab can show static Scalable
Vector Graphics images. This needs the Apache Software Foundation
Batik package being installed. The following examples will
download a big (2.8 MB) jar file if Batik is not installed on your
If a system has two screens available then PXLab is able to control
two monitors. The following design file
emulates this on two windows. If this design file is run as an
application it should be run with option '-S 6 -w 440 -h 440' on
single screen systems and with option '-S 8' on dual screen systems.
This next example shows stereo
pictures on a dual screen system with uncrossed disparity
viewing. You might not have such a system, but if you do then you
can see 3D pictures (use option -S8 for dual screen display).
PXLab contains several different types of response objects. These are stimulus elements which collect data from the subject in a special way.
This example records the time and position of a mouse button
Here is an example for
collecting single choice response data.
Here is an example for
collecting multiple choice questionnaire data with single selection items.
And this example collects
responses on a rating scale.
There is a special response object for text string responses. It
collects keyboard input until the RETURN key is pressed.
This design contains GO and NOGO tasks and shows
how to control for these.
See response key codes echoed by the key_code.pxd design file. This example also
shows how an experiment can be stopped depending upon the subject's response.
This design file shows how subject
groups are set up and how blocks can be assigned to subject
groups. Note that subject groups are treated as covariate factors and
the design file lists all possible levels of the covariate factor
'subject group'. The file also defines all other factors of the design
in order to automatically create a proper data file.