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 prerecorded 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.     

The adaptation to sensory information in the production of bimanual movement patterns

Bimanual in-phase and anti-phase patterns were performed in the transverse plane under optimal and degraded proprioceptive conditions, i.e., without and with tendon vibration. Moreover, proprioceptive information was changed midway into each trial to examine on-line reorganization. In addition to the proprioceptive perturbation, the availability of visual information was manipulated to study to which degree sensory information from different modalities interact. Movement patterns performed under identical sensory conditions were compared, i.e., the first 15 s (control) and the 15 s following a change in afferent input (transfer). In the control and transfer conditions, movements with vibrations were less accurate than those without vibrations indicating the influence of optimal proprioceptive information in the calibration and recalibration of intrinsic bimanual movement patterns. Furthermore, pattern stability was affected by the nature of the transfer condition. This indicated that the degree of fluctuations in a sensory transfer situation depended upon the quality of the proprioceptive information experienced in the initial conditions. The influence of visual information was not without importance, although the nature of the coordination mode must be taken into account. In the control conditions, in-phase movements were less stable when vision was absent, whereas anti-phase movements were more stable when vision was not present. This observation was made independent of the available proprioceptive information revealing differences in visual guidance between both coordination modes. In the transfer conditions, pattern stability was similar during the vision and no-vision conditions suggesting a limited influence of visual information in the recalibration process.     

Limited visual control of the intelligibility of speech in face-to-face dialogue

Speakers are thought to articulate individual words in running speech less carefully whenever additional nonacoustic information can help listeners recognize what is said (Fowler & Housum, 1987; Lieberman, 1963). Comparing single words excerpted from spontaneous dialogues and control tokens of the same words read by the same speakers in lists, Experiment 1 yielded a significant but general effect of visual context: Tokens introducing 71 new entities in dialogues in which participants could see one another’s faces were more degraded (less intelligible to 54 naive listeners) than were tokens of the same words from dialogues with sight lines blocked. Loss of clarity was not keyed to momentto-moment visual behavior. Subjects with clear sight lines looked at each other too rarely to account for the observed effect. Experiment 2 revealed that tokens of 60 words uttered while subjects were looking at each other were significantly less degraded (in length and in intelligibility to 72 subjects) vis-à-vis controls than were spontaneous tokens of the same words produced when subjects were looking elsewhere. Intelligibility loss was mitigated only when listeners looked at speakers. Two separate visual effects are discussed, one of the global availability and the other of the local use of the interlocutor’s face.     

Lateral bias in infant chimpanzees (Pan troglodytes)

This study documents the presence, strength, and direction of lateralization in chimpanzees (Pan troglodytes) over the first 3 months of life. Nursery-reared chimpanzees (7 males and 5 females) were repeatedly assessed on a behavioral scale. Lateral bias was measured for 4 behaviors: hand-to-mouth, hand-to-hand, defensive grasp, and first step. Hand-to-mouth was significantly lateralized for the sample. Eight of the 10 chimpanzees that showed hand-to-mouth used the right hand. Lateral bias for defensive grasp was positively related to lateral bias both of first step and of hand-to-mouth. Lateral bias in hand-to-mouth was inversely related to lateral bias in hand-to-hand. Strength of lateralization increased as chimpanzees matured. These laterality effects in infant chimpanzees were expressed under conditions of emotional arousal. Moreover, degree of laterality may be a predictor of responsivity to stress.     

Kinematics of aiming in direction and amplitude: a developmental study.

The patterns of aimed movements to visual targets were analyzed in children aged 6, 8 and 10. Tasks with direction and/or amplitude requirements were used. The tasks were performed both with and without vision. Peak velocity, acceleration and deceleration and their relative temporal occurrence were evaluated. Overall, the 6- and 10-year-olds exhibited higher peak velocity and acceleration when performing the pure directional task than when performing tasks with an amplitude or stopping requirement. On the contrary, 8-year-olds showed similar peak acceleration and velocity across all three tasks. Similarly, when performing the pure directional task, the 6- and 10-year-olds reached their peak velocity and acceleration relatively later in time than the 8-year-olds. Vision of movement increased the peak velocity in all experimental tasks and peak acceleration was increased only in the pure directional task. Thus, movement kinematics varied according to the task requirements and age. Eight-year-olds showed greater propensity to feedback control in all tasks, suggesting an over-inhibition in their approach patterns, whereas 10-year-olds tended to use feedforward processes, with a shortened deceleration phase.     

Evolutionary roots of intuitive parenting: Maternal competence in chimpanzees

Intuitive parenting behaviours have been shown to be universal in humans and appear to be based on psychobiological preadaptedness. This study is an exploration of the evolutionary roots of intuitive parenting through naturalistic observation of mother chimpanzees' interaction with their very young infants. Maternal competence is demonstrated initially through the behaviours of carrying the newborn infant and allowing the infant to nurse. Very early mother–infant interactions include play, ‘exercise’, cradling and grooming. Chimpanzee mothers also assess their offspring's behavioural state and muscle tone through visual inspections and movement of legs, arms, fingers and toes. Chimpanzee mothers and infants, as early as 2 weeks of age, spend some time in mutual gaze. Neonatal chimpanzees are capable of sustained face-to-face interactions, as these were observed in nursery-reared chimpanzee interactions with human adults; however, it appears that chimpanzee mothers encourage mutual gaze with their infants for only brief durations. Chimpanzees with good maternal competence exhibit sensitive responsivity to infants' communicatory signals. Thus the results of this study support the claim that there are evolutionary and comparative foundations of intuitive parenting evident in the maternal behaviour and maternal competence of chimpanzees.