Example of an old/new recognition experiment.

This is an example of a simple old/new recognition experiment. It is split
into two phases, a study phase and a test phase:

Study phase:

In the study phase, the subject is presented with 3 images of objects in
randomized presentation order and has to learn/memorize them. Each image
is presented for a ‘duration’ of 2 seconds, then the image disappears and
the subject has to advance to the next presentation by pressing the ‘n’
key on the keyboard. The list of ‘study’ objects is read from the file

Test phase:

In the test phase, the subject is presented with test images defined in
the file ‘testlist.txt’, again in randomized order. Test images are
presented for a ‘duration’ of 0.5 seconds or until the subjects responds
with a keypress. The subject has to press one of two keys, telling if the
test image is an “old” image - previously presented in the study phase,
or a “new” image - not seen in the study phase. The keys used are ‘c’ and
‘m’, the mapping of keys to response (“old” or “new”) is selected by the
input argument “hand” – allowing to balance for handedness of subjects /
response bias.

At the end of a session (when all images in the ‘testlist.txt’ have been
presented and tested), the results - both response of the subject and its
reaction time - are stored to a file ‘OldNewRecogExp_xx.dat’, where ‘xx’
is the subject number given as input argument “subNo” to this script.

Input parameters:

subNo subject number; use subNo>99 to skip check for existing file
hand response mapping for test phase

e.g.: OldNewRecogExp(99,1);

Example DESIGN:

STUDY PHASE: study 3 objects
TEST PHASE: shown 6 objects, decide whether the object is old or new

This script demonstrates:

  • reading from files to get condition on each trial
  • randomizing conditions (for the study and test phase)
  • showing image/collecting response (response time, accuracy)
  • writing data to file “OldNewRecogExp_<subNo>.dat

Please refer to other included demos for new functions of Psychtoolbox-3
vs. the old Psychtoolbox-2.

Other than a few changes how to call the Screen function,
and the try … catch statements, this code replicates a
typical OS9 experiment

NOTE to previous MacOS-9 users: OSX is case sensitive!!!


05/24/05 Quoc Vuong, PhD, University of NewCastle wrote and contributed
it, as an example for usage of Psychtoolbox-3, Version 1.0.6.
03/01/08 Mario Kleiner modified the code to make use of new functionality
added in Psychtoolbox 3.0.8.

Path   Retrieve current version from GitHub | View changelog