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Facilities

We are located in Department of Psychological & Brain Sciences at Indiana University (Campus Map).

Facilities include:

A Virtual Reality lab for the study of distance, size and shape perception in visually guided reaching. The components include an SGI Octane computer, a 2-marker Flock of Birds, and a Virtual Research HMD.

One limitation of the VR set-up is an artificial decoupling of accommodation and vergence - the display geometry specifies an object at some distance; however, this display is presented on screens within the HMD that are only millimeters from the eye. This conflict causes some instability to depth perception, and while this instability does have some methodological value, we do need to perform our experiments in the actual environment to ensure the VR data is generalizable.

For concurrent study of reaching to real objects, we use an OPTOTRAK kinematic measurement system. A half-silvered mirror produces reach targets by reflecting the position of an actual object. This avoids the accommodation/vergence issues from the VR. A liquid crystal window can used to occlude vision of a target at the beginning of a reach.

Our current investigations of phase perception involve a tracking task, in which participants track a dot oscillating on a PC monitor at some frequency and at some relative phase. Participants control their dot using a joystick which is occluded. Using a version of ExpLib, we are able to carefully manipulate aspects of the mapping between the behavior of the joystick and the dot it is controlling. This enables us to control the phase relation between the joystick and the target dot independently of the instructions regarding the phase relation between the two dots.

Display generation using dynamical modeling and animation software is accomplished on various Macintosh computers. Both Macs, PCS and an SGI Indy are used for transformation and analysis of kinematic and psychophysical data. In the past a re-instrumented flatbed plotter has been used to control moving targets for reaching.

Our lab also has the all important kitchen area for making coffee, and a whiteboard that primarily serves as cognitive scaffolding for Andrew. The two PCs do double duty by running the Optotrak and the second Flock of Birds units respectively, as well as work stations for lab personnel. We have storage space, three cubicles that serve as either office space or for running subjects, and office space for the graduate students.