The Effect of Task Complexity on Time Estimation in the Virtual Reality Environment: An EEG Study

This paper investigated the effect of task complexity on time estimation in the virtual reality environment (VRE) using behavioral, subjective, and physiological measurements. Virtual reality (VR) is not a perfect copy of the real world, and individuals perceive time duration differently in the VRE than they do in reality. Though many researchers have found a connection between task complexity and time estimation under non-VR conditions, the influence of task complexity on time estimation in the VRE is yet unknown. In this study, twenty-nine participants performed a VR jigsaw puzzle task at two levels of task complexity. We observed that as task complexity increased, participants showed larger time estimation errors, reduced relative beta-band power at Fz and Pz, and higher NASA-Task Load Index scores. Our findings indicate the importance of controlling task complexity in the VRE and demonstrate the potential of using electroencephalography (EEG) as real-time indicators of complexity level.

Growth Models of Positive Caregiving Behaviours and Concurrent Autonomic Activity in Caregivers and Children during a Challenging Puzzle Task: Replication and Extension

Caregivers exhibiting low levels of positive caregiving tend to have reduced dynamic range in high- frequency heart rate variability (HRV), an index of parasympathetic nervous system activity. Yet less is known about the involvement of the sympathetic nervous system, which may impact the plausible range of parasympathetic reactivity. Here, caregiver–child dyads completed resting assessments of HRV and pre-ejection period (PEP), followed by a videotaped puzzle task during which HRV was measured and observers coded the degree of caregivers’ positive emotionality. Multilevel modelling was employed to characterize task fluctuations in HRV as a function of resting PEP and caregivers’ positive emotional expressions. Higher frequency of caregiver positivity was associated with greater HRV reactivity in caregivers but not children. Increased caregiver positivity was correlated with longer resting PEP in children. These results replicate findings of greater caregiver parasympathetic flexibility during positive caregiving and extend those findings to children’s resting sympathetic activity.

Children Persist Less When Adults Take Over

Children need to learn to persist through challenges, yet adults sometimes step in to solve problems for them. Here, we looked at how adult taking over related to children’s persistence. In an observational study (N=34, ages 4-8), we found that parents who took over more often during a challenging puzzle task rated their children as dispositionally less persistent. To establish whether taking over can cause reduced persistence, we ran two preregistered experiments (N=150, ages 4-5). Children assigned to a taking over condition persisted less on a subsequent task compared to those in a teaching or a baseline condition. Reframing the context did not ameliorate the negative impact of taking over. The results suggest that taking over impairs children’s persistence.

Eliciting Naturalistic Conversations: A Method for Assessing Communication Ability, Subjective Experience, and the Impacts of Noise and Hearing Impairment

Purpose The purpose of this study was to introduce a method of eliciting conversational behavior with many aspects of realism, which may be used to study the impacts of hearing impairment and noise on verbal communication; to describe the characteristics of speech and language participants produced during the task; and to assess participants' engagement and motivation while completing the task. Method Twenty young adults with normal hearing and 20 older adults with hearing impairment took part in face-to-face conversations while completing a referential communication puzzle task designed to elicit natural conversational speech production and language with a number of realistic characteristics. Participants rated the difficulty and relevance of acoustic scenes for communication and their engagement in conversations. Results The communication task elicited speech production in a natural conversational register and language with many realistic characteristics, including complex linguistic constructions and typical disfluencies found in everyday speech, and approximately balanced contributions within dyads. Subjective ratings suggest that the task is robust to learning and fatigue effects and that participants remained highly engaged throughout the experiment. All participants were able to maintain successful communication regardless of background noise level and degree of hearing impairment. Conclusions The communication task described here may be used as part of a functional assessment of the ability to communicate in the presence of noise and hearing impairment. Although existing speech assessments have many strengths, they do not take into account the inherently interactive nature of spoken communication or the effects of motivation and engagement.

Joint Segmentation Methods of Tumor Delineation in PET – CT Images: A Review

Segmentation is one of the crucial steps in applications of medical diagnosis. The accurate image segmentation method plays an important role in proper detection of disease, staging, diagnosis, radiotherapy treatment planning and monitoring. In the advances of image segmentation techniques, joint segmentation of PET-CT images has increasingly received much attention in the field of both clinic and image processing. PET - CT images have become a standard method for tumor delineation and cancer assessment. Due to low spatial resolution in PET and low contrast in CT images, automated segmentation of tumor in PET - CT images is a well-known puzzle task. This paper attempted to describe and review four innovative methods used in the joint segmentation of functional and anatomical PET - CT images for tumor delineation. For the basic knowledge, the state of the art image segmentation methods were briefly reviewed and fundamental of PET and CT images were briefly explained. Further, the specific characteristics and limitations of four joint segmentation methods were critically discussed.