Archive for July, 2009

Effects of Damping Head Movement and Facial Expression in Dyadic Conversation Using Real-Time Facial Expression Tracking and Synthesized Avatars

Thursday, July 9th, 2009

Boker, S. M., Cohn, J. F., Theobald, B.-J., Matthews, I., Brick, T. & Spies, J. (in press) Effects of Damping Head Movement and Facial Expression in Dyadic Conversation Using Real-Time Facial Expression Tracking and Synthesized Avatars. Philosophical Transactions of the Royal Society B.

This article reports an experiment in which research assistants’ head movements and facial expressions were motion tracked during videoconference conversations, an avatar face was reconstructed in real time, and naive participants spoke with the avatar face. Research assistants’ facial expressions, vocal inflections, and head movements were attenuated at one minute intervals in a fully crossed experimental design. Attenuated head movements led to increased head nods and lateral head turns, and attenuated facial expressions led to increased head nodding in both naive participants and in confederates. The results are consistent with a hypothesis that the dynamics of head movements in dyadic conversation include a shared equilibrium.

(a) four facial expression (b) four attenuated facial expression.

The manuscript of this article accepted for publication can be downloaded as a PDF. This preprint may not exactly replicate the final version published in the journal. It is not the copy of record.

Time Delay Embedding Increases Estimation Precision of Models of Intraindividual Variability

Wednesday, July 1st, 2009

von Oertzen, T. & Boker, S. (in press) Time Delay Embedding Increases Estimation Precision of Models of Intraindividual Variability. Psychometrika

An article describing a surprising result for estimating dynamical systems models was recently accepted for publication by Psychometrika. Publication rules for Psychometrika prohibit us from quoting excerpts or distributing the manuscript on the web, but we can send a preprint if you send one of the authors an email request.

Spatiotemporal Symmetry and Multifractal Structure of Head Movements

Wednesday, July 1st, 2009

Ashenfelter, K. T., Boker, S. M., Waddell, J. R., & Vitanov, N. (in press). Spatiotemporal Symmetry and Multifractal Structure of Head Movements during Dyadic Conversation. Journal of Experimental Psychology: Human Perception & Performance

This study examined the influence of sex, social dominance, and context on motion-tracked head movements during dyadic conversations. Windowed cross-correlation analyses found high peak correlation between conversants’ head movements over short (2 second) intervals and a high degree of nonstationarity. Nonstationarity in head movements was found to be related to gender of the participants. Multifractal analysis found small-scale fluctuations to be persistent, and large-scale fluctuations to be antipersistent. These results are consistent with a view that symmetry is formed between conversants over short intervals and that this symmetry is broken at longer, irregular intervals.

(a) Coordination between dancers is mostly stationary (b) Coordination during conversation is highly nonstationary.

The manuscript of this article accepted for publication can be downloaded as a PDF. This article may not exactly replicate the final version published in the APA journal. It is not the copy of record.

Describing Intraindividual Variability at Multiple Time Scales Using Derivative Estimates

Wednesday, July 1st, 2009

Deboeck, P. R., Montpetit, M. A., Bergeman, C. S. & Boker, S. M. (in press). Describing Intraindividual Variability at Multiple Time Scales Using Derivative Estimates. Psychological Methods.

Studying intraindividual variability can be made more productive by examining variability of interest at specific time scales, rather than considering the variability of entire time series. Examination of variance in observed scores may not be sufficient, as these neglect the time scale dependent relationships between observations. This article outlines a method to examine intraindividual variability through estimates of the variance and other distributional properties at multiple time scales using estimated derivatives.

The manuscript of this article accepted for publication can be downloaded as a PDF. This article may not exactly replicate the final version published in the APA journal. It is not the copy of record.

Mapping and Manipulating Facial Expression

Wednesday, July 1st, 2009

Theobald, B., Matthews, I., Mangini, M., Spies, J., Brick, T., Cohn, J. F., & Boker, S. (2009) Mapping and Manipulating Visual Prosody. Language and Speech 52:2, 369-386.

This article, just published in Language and Speech, describes the process by which we are mapping facial expressions from one individual to another in real time.

The manuscript as it was submitted can be downloaded as a PDF