Object Trimming Demonstration

Object trimming is the finding that two dots, which flank a target’s edge, can perceptually trim the neighboring portion of that target.

This page contains two demonstrations of object trimming. The first was created as a .wmv movie and the second was created using Authorware V6.0.

These demonstrations should give the viewer a "feel" for object trimming. Bear in mind that the timing of web-based delivery may differ from the timing used in a lab-based setting.

Demo 1 -

We recommend that you (1) view this movie file in "full screen" mode (if you are using Windows Media Player to view the movie you can do this by pressing "alt" and "enter" simultaneously) and that you (2) pause the movie on the instructions page until you fully understand the task. click here.

Demo 2 -

This second demonstration was created using Macromedia Authorware V6.0. We created this program so that it will run either locally on any PC computer or online through a web browser. However this demo was created in 2010 and most current web browsers will no longer play the web-based version. In our testing the executable version of the demonstration still works on Windows computers.

Click here to download the executable version that will run on your PC computer (zip format). You will need to extract all of these files using WinZip (or a similar program). When you extract the files you should have "BistableJEPHPP.exe" and "Ftp.u32" located in a unique directory and the files "BMPVIEW.X32", "MIX32.X32", "WMFVIEW.X32", & "VIEWSVC.X32" located in a subfolder entitled "XTRAS". Note: It is important to maintain this file structure -- do NOT move the files out of the XTRAS folder.

Click here to try the online version. This demo was created in 2010 and most current web browsers will not play this version of the demo. If you want to try using this version of the demo then click here to download the free plugin. (Use the "installer full" version.)

Note: This site has links to two demonstrations only, not the exact experiments reported in:
• Kahan, T. A., & Enns, J. T. (2010). Object trimming: When masking dots alter rather than replace target representations. Journal of Experimental Psychology: Human Perception and Performance, 36, 88-102.

For more on object trimming (and a related effect we call "object binding") see:
• Kahan, T. A. (2016). What dot-based masking effects can tell us about visual cognition: A selective review of masking effects at the whole-object and edge-based levels. B. H. Ross (Ed.) The Psychology of Learning and Motivation, Vol. 64.
• Kahan, T. A., & Enns, J. T. (2014). Long-term memory representations influence perception before edges are assigned to objects. Journal Of Experimental Psychology: General, 143(2), 566-574.