CULTURAL MODELS OF INFANT EMOTIONS AND NEEDS AMONG THE GAMO PEOPLE OF SOUTHERN ETHIOPIA

How mothers perceive their infants’ emotions and their subsequent responses are influenced by cultural values and beliefs. Mothers who live in particularly harsh environments may have perceptions about their infants’ emotions that reflect not only cultural values but also constraints of the environment. In this qualitative study, 29 Gamo mothers living in rural Ethiopia were interviewed about perceptions of their infants’ emotions, how they felt about these emotions, and what they believed their infants needed in response. Through constant comparative analysis and thematic coding, several patterns emerged in mothers’ perceptions about their infants’ emotions and what constituted appropriate responses. Mothers said that their infants’ negative emotions were possibly related to illness and that appropriate responses were focused mostly on breastfeeding, complementary food, and needing to be held. Mothers also discussed their work demands and how they conflicted with their desire to respond to their infants; however, many mothers said that they relied on their older children to help. Mothers’ responses were centered on a parenting strategy aimed at promoting infant health and survival, which is consistent with research on parents living in rural environments who subsist by farming and have relatively high risk for infant mortality.     

Newborns’ attention is driven by the translational movement

The present study investigated whether 2-day-old newborns are able to discriminate two translating meaningless Point-Light Displays (PLD) videos, in which the shape of one of them changes compared to that of the other along the trajectory, independently from movement kinematics, and if this ability is present both when stimuli differed at the end or at the beginning of the movement. To manipulate the instant in which along the movement the difference between stimuli was evident, and to maintain every unspecific dissimilarity possibly determining the preference, videos were played in a loop either forward or backwards. In Experiment 1, PLD stimuli moved with natural accelerated-decelerated kinematics; in Experiment 2 they moved at constant velocity. Four groups of newborns were submitted to the preferential looking technique experiments. Results showed that newborns looked longer at natural kinematics and that, irrespective of the type of kinematics, they discriminated the two stimuli only when videos were played forward, that is, only when stimuli differed at the end of the movement. These data suggest that, independently from kinematics, movement translational components induce newborns to allocate attention at the end of the observed movement. Given the strict link between attention and eye movements, we suggest that this effect may bootstrap the system and give rise to proactive gaze, the typical gaze behaviour present during executed and observed goal-directed actions.     

Arm position influences the activation patterns of trunk muscles during trunk range-of-motion movements

To understand the activation patterns of the trunk musculature, it is also important to consider the implications of adjacent structures such as the upper limbs, and the muscles that act to move the arms. This study investigated the effects of arm positions on the activation patterns and co-activation of the trunk musculature and muscles that move the arm during trunk range-of-motion movements (maximum trunk axial twist, flexion, and lateral bend). Fifteen males and fifteen females, asymptomatic for low back pain, performed maximum trunk range-of-motion movements, with three arm positions for axial twist (loose, crossed, abducted) and two positions for flexion and lateral bend (loose, crossed). Electromyographical data were collected for eight muscles bilaterally, and activation signals were cross-correlated between trunk muscles and the muscles that move the arms (upper trapezius, latissimus dorsi). Results revealed consistently greater muscle co-activation (higher cross-correlation coefficients) between the trunk muscles and upper trapezius for the abducted arm position during maximum trunk axial twist, while results for the latissimus dorsi-trunk pairings were more dependent on the specific trunk muscles (either abdominal or back) and latissimus dorsi muscle (either right or left side), as well as the range-of-motion movement. The findings of this study contribute to the understanding of interactions between the upper limbs and trunk, and highlight the influence of arm positions on the trunk musculature. In addition, the comparison of the present results to those of individuals with back or shoulder conditions may ultimately aid in elucidating underlying mechanisms or contributing factors to those conditions.     

Non-verbal IQ is correlated with visual field advantages for short duration coherent motion detection in deaf signers with varied ASL exposure and etiologies of deafness

Studies have reported a right visual field (RVF) advantage for coherent motion detection by deaf and hearing signers but not non-signers. Yet two studies [Bosworth R. G., & Dobkins, K. R. (2002). Visual field asymmetries for motion processing in deaf and hearing signers. Brain and Cognition, 49, 170-181; Samar, V. J., & Parasnis, I. (2005). Dorsal stream deficits suggest hidden dyslexia among deaf poor readers: Correlated evidence from reduced perceptual speed and elevated coherent motion detection thresholds. Brain and Cognition, 58, 300-311.] reported a small, non-significant RVF advantage for deaf signers when short duration motion stimuli were used (200-250 ms). Samar and Parasnis (2005) reported that this small RVF advantage became significant when non-verbal IQ was statistically controlled. This paper presents extended analyses of the correlation between non-verbal IQ and visual field asymmetries in the data set of Samar and Parasnis (2005). We speculate that this correlation might plausibly be driven by individual differences either in age of acquisition of American Sign Language (ASL) or in the degree of neurodevelopmental insult associated with various etiologies of deafness. Limited additional analyses are presented that indicate a need for further research on the cause of this apparent IQ-laterality relationship. Some potential implications of this relationship for lateralization studies of deaf signers are discussed. Controlling non-verbal IQ may improve the reliability of short duration coherent motion tasks to detect adaptive dorsal stream lateralization due to exposure to ASL in deaf research participants.     

Evidence for distinct contributions of form and motion information to the recognition of emotions from body gestures

The importance of kinematics in emotion perception from body movement has been widely demonstrated. Evidence also suggests that the perception of biological motion relies to some extent on information about spatial and spatiotemporal form, yet the contribution of such form-related cues to emotion perception remains unclear. This study reports, for the first time, the relative effects on emotion recognition of inverting and motion-reversing patch-light compared to fully illuminated displays of whole-body emotion gestures. Inverting the gesture movies or playing them backwards significantly impaired emotion classification accuracy, but did so more for patch-light displays than for identical but fully illuminated movement sequences. This result suggests that inversion impairs the processing of form information related to the configuration of body parts, and reversal impairs the sequencing of form changes, more than these manipulations impair the processing of kinematic cues. This effect was strongest for inversion, suggesting an important role for configural information in emotion recognition. Nevertheless, even in combination these stimulus manipulations did not abolish above chance recognition of any of the emotions, suggesting that kinematics help distinguish emotions expressed by body gestures. Disproportionate impairments in recognition accuracy were observed for fear and disgust under inversion, and for fear under motion reversal, suggesting a greater role for form-related cues in the perception of these emotions.     

Common mechanisms in apparent motion perception and visual pattern matching

There are close functional similarities between apparent motion perception and visual pattern matching. In particular, striking functional similarities have been demonstrated between perception of rigid objects in apparent motion and purely mental transformations of visual size and orientation used in comparisons of objects with respect to shape but regardless of size and orientation. In both cases, psychophysical data suggest that differences in visual size are resolved as differences in depth, such that transformation of size is done by translation in depth. Furthermore, the process of perceived or imagined translation appears to be stepwise additive such that a translation over a long distance consists of a sequence of smaller translations, the durations of these steps being additive. Both perceived and imagined rotation also appear to be stepwise additive, and combined transformations of size and orientation appear to be done by alternation of small steps of pure translation and small steps of pure rotation. The functional similarities suggest that common mechanisms underlie perception of apparent motion and purely mental transformations. In line with this suggestion, functional brain imaging has isolated neural structures in motion area MT used in mental transformation of size.     

Infants’ cortical processing of biological motion configuration – A fNIRS study

Biological motion perception is a key component of action perception contributing to social cognition in crucial ways. Contemporary neuroimaging studies show that biological motion is processed differently in the human brain from other types of motion. In particular, the right posterior Superior Temporal Sulcus (rpSTS), an area known for its central role in social perception, has been consistently associated with the perception of biological motion in the mature brain. By contrast, most findings investigating the development of biological motion perception in infancy come from behavioral studies, and far less is known regarding the right STS’ role in processing biological motion.The current study used fNIRS to measure brain activation to biological motion in the rSTS region of 7–8-month-old infants. Infants were presented with two conditions: an approaching coherent motion of a person walking (coherent point-light-walker, PLW); and a spatially scrambled version of this display, where the global configuration of a person walking was disrupted (scrambled PLW).We found a functional activation, i.e., a significant increase in HbO₂ concentration in relation to baseline, in the right middle-posterior temporal cortex only when infants viewed the coherent point-light-walker. This activation statistically differed from the scrambled point-light-walker, and no significant activations were found for viewing the scrambled motion.Our study adds evidence pointing to rSTS’ sensitivity to the global human configuration in biological motion processing during infancy. The rSTS seems thus to become functionally specialized in biological motion configuration as early as at 7–8 months of age.     

运动觉、布局无关运动与路径整合

路径整合是空间导航的一个重要子领域。本研究采用了一种三角形完成任务的新变式来研究路径整合问题，发现在剥夺被试的视觉输入的前提下，去除被试部分运动觉后，其绩效有不同水平的下降；同时还发现在编码过程中与路径布局无关的不同方向旋转间并无显著性差异。此外，由于本研究是在室外空间中所做的现场研究，故得到的结果优于室内所做的经典研究，进而验证了前人的一个猜测。     

The perception of biological and mechanical motion in female fragile X premutation carriers

Previous studies reported impaired visual information processing in patients with fragile X syndrome and in premutation carriers. In this study, we assessed the perception of biological motion (a walking point-light character) and mechanical motion (a rotating shape) in 25 female fragile X premutation carriers and in 20 healthy non-carrier controls. Stimuli were moving stimulus dots embedded among a cloud of noise dots. Sensitivity (d′) for motion detection was determined. Emotional symptoms were assessed by Hamilton’s depression and anxiety rating scales. Results revealed that the premutation carriers displayed lower sensitivities for biological and mechanical motion relative to the non-carriers. This deficit was more pronounced in the case of biological stimuli. The premutation carriers displayed higher depression and anxiety scores relative to the non-carriers. Higher depression, but not anxiety, scores were associated with decreased sensitivity for biological, but not mechanical, motion in the carrier group. These results suggest that motion perception deficits are detectable in fragile X premutation carriers, and that the impairment of biological motion perception is associated with depressive symptoms.