Eyetracking for two-person tasks with manipulation of a virtual world.

Eyetracking facilities are typically restricted to monitoring a single person viewing static images or pre-recorded video. In the present article, we describe a system that makes it possible to study visual attention in coordination with other activity during joint action. The software links two eyetracking systems in parallel and provides an on-screen task. By locating eye movements against dynamic screen regions, it permits automatic tracking of moving on-screen objects. Using existing SR technology, the system can also cross-project each participant's eyetrack and mouse location onto the other's on-screen work space. Keeping a complete record of eyetrack and on-screen events in the same format as subsequent human coding, the system permits the analysis of multiple modalities. The software offers new approaches to spontaneous multimodal communication: joint action and joint attention. These capacities are demonstrated using an experimental paradigm for cooperative on-screen assembly of a two-dimensional model. The software is available under an open source license.

Structural influences on initial accent placement in French.

In addition to the phrase-final accent (FA), the French phonological system includes a phonetically distinct Initial Accent (IA). The present study tested two proposals: that IA marks the onset of phonological phrases, and that it has an independent rhythmic function. Eight adult native speakers of French were instructed to read syntactically ambiguous French sentences (e.g., Les gants et les bas lisses 'the smooth gloves and stockings') in a way that disambiguated the scope of the adjective. When the final adjective (lisses) applies to the conjoined NP, a prosodic boundary is warranted immediately before the adjective; when it applies to the second NP alone, a boundary before that NP is more appropriate. Length of the second noun and the adjective were varied from one to four syllables to investigate length-related tendencies toward phonological boundary marking and toward rhythmic placement of IA. For the materials from six speakers whose readings were correctly interpreted by native listeners, incidence of word-initial prosodic peaks was affected by both structure and length, with most reliable occurrence at onsets of Minor/Phonological Phrases. The only effect of rhythmicity independent of phrase structure was omission of FA in stress clash with IA.