Eye Tracking Technology and Television Courtroom Broadcasting

August 10, 2010

Television courtroom broadcasting effects are seldom researched empirically.  While camera technology and its effects may often be hotly debated, technology may now be able to give us definitive answers to questions about the effects which have been the subject of so much research. This article briefly highlights the possibilities of eye tracking technology.


The US Supreme Court effectively called for more empirical research on the issues surrounding the effects of television courtroom broadcasting in two seminal cases of Estes[1] and Chandler,[2]  and recently in Hollingsworth.[3]  For various reasons the challenge has not been fully taken up. Substantial gaps in the research remain. Problems also remain in attempting to measure the effects of such broadcasts via self reports, opinion reports and questionnaires.  Eye tracking technology can fill in some of the gaps as to the in-court effects.

Eye Tracking Technology

Eye trackers study the position and movements of the eye. They consist of complex pieces of hardware and software.  There are various types and manufacturers.[4]  Eye tracking measures eye[5]: fixation (gaze); fixation duration, fixation rate, mean fixation duration, number of fixations, scanpath (fixation sequence), area of interest (AOI), gaze percentage (proportion of time) per AOI, number of fixations per AOI, gaze duration mean per AOI,  visits, re-visits, and task completion duration.[6] 

Eye tracking research and techniques[7] are used successfully in advertising, marketing, internet usage research, health, psychology (e.g. eyewitness identification research,[8] and police video interviews).[9]  There are indeed such a range of uses that it is impossible to particularise them all here. 

Eye tracking technology was not considered by the US Supreme Court when considering the effects of television courtroom broadcasting.  Neither is it considered in the general literature on the subject. But eye tracking technology can assist in conducting research of attraction and distraction effects of television courtroom broadcasting cameras i.e. monitoring where exactly courtroom participants are looking.  We can now research actual effects, without having to rely solely on limited self reports and opinion reports. 

Empirical Research

The Supreme Court recognised that television courtroom broadcasting may have subtle and/or discrete effects, some so subtle as to defy detection by the court participants.[10]  Eye tracking ensures that such effects are now no longer so subtle as to defy detection.  The eye movements of simulated courtroom actors in test settings and in actual court settings can be examined.   

Eye tracking may be applied to television courtroom broadcasting participants to monitor attention and distraction effects. For example: 

·               Do they look at the television camera?

·               If so, for how long?

·               What is the effect?

·               What difference does the location of the camera have on the different courtroom actors?

·               Are there different effects for camera only versus camera plus cameraman?

·               Are there different effects for different types of camera?

·               How do in-court television cameras affect the different courtroom actors while undertaking tasks? 

There are various types of eye trackers.  One avenue for in-court research is to use eye trackers which are incorporated into lightweight glasses.[11]  This type of research allows itself to be adopted to different courtroom actors and also in realistic settings and in real (non-live) court settings.  There are also various types of head mounted eye tracking tools.[12]

In considering different television courtroom broadcasting forms and in particular long extended footage versus short or snippet footage, we need to research what is viewed, for how long, eye movement behaviour and visual processing speeds.[13]


Eye tracking permits testing and direct observation of fixation, focus and attention.[14]  It tracks and documents exactly what people see – and what they ignore.[15]  It ‘provides a more direct [test than] manual measurements’.[16]  It also has potential to test and overcome the limitations of opinion reports and self reports. ‘[E]ye movements are a direct indicator of overt attention’ and provide ‘a highly direct measure of visual attention, … [and] eye movements’. [17]  We have advanced research tools with eye trackers. The US Supreme Court never thought this was possible.  We should exploit this opportunity presented by technology.   

Paul Lambert BA, LLM, Solicitor, CTMA is a PhD candidate at Trinity College, Dublin.  Some of these points were presented at the 10th European Conference on eGovernment on 17-18 June 2010.


[1]           Estes v Texas, 381 US (1965), at 532 – 616.

[2]           Chandler v Florida 449 US (1981), at 560 (1981). 

[3]           Hollingsworth v Perry, 558 US _ 2010, available at http://www.supremecourt.gov/opinions/09pdf/09A648.pdf.

[4]           See www.tobii.com; www.eyetracking.com; http://www.smivision.com/en/gaze-and-eye-tracking-systems/home.html; http://www.arringtonresearch.com/; http://www.asleyetracking.com/Site/; http://www.polhemus.com.

[5]           R.J.K. Jacob and K.S. Karn, Eye Tracking in Human-Computer Interaction and Usability Research: Ready to Deliver the Promises, in J. Hyona, R. Radach and H. Deubel, Eds, The Mind’s Eye: Cognitive and Applied Aspects of Eye Movement Research, (Amsterdam, The Netherlands: Elsevier Science, (2003), 573 – 605, referred to id, 173.  Such research relies on sophisticated software (see reference id, 88 – 91).  Detailed experience and expertise with software, computers, computer science and statistics can also be a prerequisite to undertaking such studies.  Note also, id. 171) and hardware tools, as well as calibration of those tools (see comments in relation to calibration issues, id. 87 – 99, and 301).

[6]           Also V. Sundstedt, Eye Tracking in User Studies, SIGGRAPH 2009, New Orleans, http://www.siggraph.org/s2009/, and also http://www.scss.tcd.ie/Veronica.Sundstedt/.

[7]           See A. Duchowski, Eye Tracking Methodology, Theory and Practice, 2nd edition, (London: Springer, 2007), regarding eye tracking techniques generally, at 52 – 86.

[8]           S. Josephson and M. Holmes, Have You Seen Any of These Men?  Looking at Whether Eyewitnesses Use Scanpaths to Recognize Suspects in Photo Lineups, ETRA, Proceedings of the 2010 Symposium on Eye-Tracking Research & Applications, Austin, Texas, March 22 – 24, 2010.  As originally used by G.R. Loftus and N.H. Mackworth, Cognitive Determinants of Fixation Location During Picture Viewing 4:4 Journal of Experimental Psychology 565-572 (1978).  See description in L.J. Ware., below, 34 – 35.

[9]           See G.D. Lassiter and A.A. Irvine, Videotaped Confessions: The Impact of Camera Point of View on Judgements of Coercion, 16 Journal of Applied Social Psychology 286 – 276 (1986).

[10]          Id. at 544-545.  Clarke, J.

[11]          See example reference to same at http://www.eyetracker.co.uk/.

[12]          In terms of head mounted display applications see discussion in C.D. Wickens, M. Vincow and M. Yeh, Design Applications of Visual Spatial Thinking: The Importance of Frame of Reference, in P. Shah and A. Miyake, The Cambridge Handbook of Visuospatial Thinking (Cambridge: Cambridge University Press, 2005) 383 – 425., at 406 et seq.

[13]          Note recent research by M.L.-H. Vo and W.X. Schneider, A Glimpse is not a Glimpse: Differential Processing of Flashed Scene Previews Lead to Differential Target Search Benefits, 18: 2 Visual Cognition 171 – 200 (2010).

[14]          See L.J. Ware, above, 11.

[15]          See http://www.prsresearch.com/prs-tools/.

[16]          Id.

[17]          Id.