Academic journal article Human Factors

Telepresence in Videocommunications: A Study on Stereoscopy and Individual Eye Contact

Academic journal article Human Factors

Telepresence in Videocommunications: A Study on Stereoscopy and Individual Eye Contact

Article excerpt

We conducted two experiments to investigate how stereoscopy and technologies that allow individual eye contact affect the impression of telepresence in videoconferencing. Telepresence is defined as the degree to which participants of a telemeeting get the impression of sharing space with the remote site. Results revealed, among other things, that stereoscopy increases telepresence and makes videoconferencing more attractive. In addition, we found that reduced eye contact angles enhance the recognizability of individually addressed nonverbal signals. However, a setup that eliminates horizontal and vertical eye contact angles seems to be advantageous only in conferences with more than two persons per site.



Videocommunication is telecommunication with a transmission of sound and picture. In contrast to telephony, videocommunications allow the transmission of the visual components of communication, the most important of which is nonverbal behavior.

From psychological and linguistic studies (e.g., Argyle, 1975; Argyle and Cook, 1976; Cosnier and Brossard, 1984; Davis, 1979; Kendon, 1967) it is known that nonverbal behaviors fulfill many functions in person-to-person communication. For example, the turn taking in a conversation is governed to a large extent by the gaze behavior and facial expressions of the interlocutors. Paralinguistic behaviors qualify spoken statements as ironic or humorous; doubt is expressed by frowning; body movements, such as shrugging, express indifference or helplessness; and the positioning of the body toward or away from a person can express an attitude of openness or reserve.

The visual channel is also of primary importance for psychological processes such as impression formation. Visual cues, such as hair style or dress, carry socially derived information that allows people to develop an impression. People may be less certain in their judgment of character when they cannot make use of the visual channel because humans are heavily reliant on these nonobvious indicators of a person's nature or style.

As an additional benefit, the visual channel can provide a means for indicating a common focus of attention. This can be accomplished by showing something to an interlocutor (e.g., pictures and graphics), by manipulating an object, or by pointing to a section of a document.

In videocommunications the distinction is generally made between videotelephony and videoconferencing. A typical videotelephony situation involves two interlocutors, each using a videophone, which in most cases is a desktop device. Videotelephony can also be provided by means of a "video window" within a multimedia application. In videoconferencing, usually groups of people meet in videoconferencing studios, employing a point-to-point connection, sometimes with large wall-type video projection screens. Multipoint videoconferencing is a connection among more than two videoconferencing terminals or videophones.

Since the introduction of telephony 120 years ago, videotelephony and videoconferencing services have become available in many countries. Videophone calls were first demonstrated in the 1920s (Angiolillo, Blanchard, and Israelski, 1993), and the first public videotelephony service, which connected the cities of Berlin, Leipzig, Nuremberg, and Munich, existed from 1936 to 1940 (Nordby, 1991). Currently, three videocommunications technologies are being introduced: analog videotelephony, ISDN videocommunications, and broadband videocommunications.

Analog videotelephony uses the (analog) Public Switched Telephone Network (PSTN). Because of a small bit rate (about 8 kbit/s), the spatial resolution is low (e.g., 128 pixels by 112 lines luminance resolution; Early, Kuzma, and Dorsey, 1993). The screen size of a typical analog videophone is relatively small (e.g., in the range of 3 in.). The frame rate can reach up to 10 frames/s (the standard movie frame rate is 24 frames/s), but under suboptimum conditions the performance is a lot lower. …

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