Targets,tactics, and the open mouth face during play fighting in three species of primates

The play fighting of many mammals involves the nonserious use of behavior patterns derived from serious fighting. A major question of theoretical importance has been that of how, given this overlap in patterns of behavior, the animals can distinguish between playful and nonplayful intent. One proposed solution is that animals use play signals to inform each other about the playful intent of their actions. The most widely reported play signal amongst primates is the open mouth play face. The manner in which this so-called signal functions is based on correlational evidence, with most reports simply noting its presence or absence in a given species. This study involved a detailed video-based analysis of the occurrence of open mouths during the play fighting of three species of primates. One captive troop each of ring-tailed lemurs, black-handed spider monkeys, and patas monkeys was used. By examining all open mouths in the context of the species-typical style of play fighting, several conclusions were empirically verified. 1) Most open mouths occur as a functionally necessary precursor for biting. 2) Some open mouths occur as a defensive threat which deters further contact. 3) The residual open mouths which may function as contact promoting play signals, constituted about 20–25% of all open mouths by the lemurs and patas monkeys, but less than 5% for spider monkeys. These species differences appeared to arise from two causes. Firstly, the spider monkeys used another signal, the head shake, in situations where lemurs and patas monkeys used open mouths. Secondly, the style of play fighting greatly influenced the frequency and duration of open mouths. This was most marked in the face-to-face combat style of patas monkeys. These findings show that comparative studies of the occurrence and function of play signals need to take into account species-typical styles of playful combat. Aggr. Behav. 23:41–57, 1997. © 1997 Wiley-Liss, Inc.     

Tummy time without the tears: The impact of parent positioning and play

The American Academy of Pediatrics (AAP) recommends that infants spend supervised time in the prone (tummy) position to foster motor development and prevent cranial deformities. However, infants may not tolerate the position, and consequently, caregivers may avoid placing their infants in the prone position. The AAP recommends that caregivers provide toys or interaction during tummy time. We evaluated the individual and combined effects of a play mat and experimenter interaction on negative vocalizations and head elevation during tummy time—positive effects were limited. Next, we evaluated a parent-led intervention wherein mothers interacted with their infants, using a toy, while lying chest-to-chest. This intervention was associated with a reduction in negative vocalizations and an increase in head elevation for the majority of infants. Additionally, mothers rated the effectiveness of the parent-led intervention more favorably than the experimenter-led intervention, suggesting the effects of the parent-led intervention were also socially valid.     

文化的考量:积极心理学当下之困与未来

积极心理学正在经历着从闲庭信步到临渊而立的转向。这种转向,既凸显了主流心理学面临着来自以积极心理学为代表的新兴势力的挑战与压力,同时,也表明积极心理学自身暴露出的短板与局限,以及由此向文化寻求支持的一种诉求,更是为寻求破局而作出的努力。可以预见,积极心理学将会以脑认知革命到来为契机,不断理顺积极心理、脑和文化环境三者关系,实现对心理学范式变革的显著的引领作用。     

班主任协商管理行为、师生关系与小学4~6年级学生外化问题行为的相互作用关系：交叉滞后研究

为探讨班主任协商管理行为、师生关系和学生外化问题行为三者间的相互作用关系, 在1个学年中, 采用问卷法对1407名小学4~6年级学生进行3次追踪测量。交叉滞后分析结果表明：(1)班主任协商管理行为启动积极的相互作用过程, T1时的班主任协商管理行为能显著减少T2时的学生的外化问题行为、提升T2时的师生关系亲密和降低T2时的师生关系冲突, 进而显著影响T3时的班主任协商管理行为、师生关系和学生外化问题行为; (2)学生外化问题行为驱动消极的相互作用过程, T1时的学生外化问题行为能显著减少T2时的班主任协商管理行为、降低T2时的师生关系亲密和增加T2时的师生关系冲突, 进而显著影响T3时的学生外化问题行为、师生关系和班主任协商管理行为。研究结果支持动态相互作用模型, 提示班主任在警醒学生外化问题行为的负面驱动作用的同时, 可有意识地利用协商管理行为的积极驱动作用干预学生的外化问题行为。     

Horizontal Plane Head Stabilization During Locomotor Tasks

Frequency characteristics of head stabilization were examined during locomotor tasks in healthy young adults (N = 8) who performed normal walking and 3 walking tasks designed to produce perturbations primarily in the horizontal plane. In the 3 walking tasks, the arms moved in phase with leg movement, with abnormally large amplitude, and at twice the frequency of leg movement. Head-in-space angular velocity was examined at the predominant frequencies of trunk motion. Head movements in space occurred at low frequencies (< 4.0 Hz) in all conditions and at higher frequencies (> 4.0 Hz) when the arms moved at twice the frequency of the legs. Head stabilization strategies were determined from head-on-trunk with respect to trunk frequency profiles derived from angular velocity data. During natural walking at low frequencies (< 3.0 Hz), head-on-trunk movement was less than trunk movement. At frequencies 3.0 Hz or greater, equal and opposite compensatory movement ensured head stability. When arm swing was altered, compensatory movement guaranteed head stability at all frequencies. Head stabilization was successful for frequencies up to 10.0 Hz during locomotor tasks Maintaining head stability at high frequencies during voluntary tasks suggests that participants used feedforward mechanisms to coordinate head and trunk movements. Maintenance of head stability during dynamic tasks allows optimal conditions for vestibulo-ocular reflex function.     

Mechanisms Controlling Head Stabilization in the Elderly During Random Rotations in the Vertical Plane

Frequency-related response characteristics of the mechanisms controlling stabilization of the head in 10 elderly subjects were compared with response characteristics in 8 young adults. Angular velocity of the head with respect to the trunk and EMG responses of 2 neck muscles were recorded in 10 seated subjects during pseudorandom rotations of the trunk in the sagittal plane at frequencies of 0.35 to 3.05 Hz. Subjects were required to actively stabilize their heads with (VS) and without (NV) visual feedback so that voluntary mechanisms and the influence of vision could be tested. Reflex mechanisms were examined when subjects were distracted by a mental calculation task during rotations in the dark (MA). Age emerged as an influential factor in the performance of head stabilization mechanisms, and decrements in performance were even more pronounced in the older as compared with younger elderly subjects. Age effects could be seen in the (a) diminished ability to voluntarily stabilize the head, particularly with the absence of vision, (b) impaired ability to stabilize the head when cognitively distracted, and (c) appearance of a resonant response of the head. Control of head stabilization shifted from reflex mechanisms to system mechanics, probably as a result of age-related changes in the integrity of the sensory systems. The elderly's system mechanics could not effectively compensate for the disturbances, however, and instability was the result.     

Continuous versus discrete dimensions of reinforcement schedules: An integrative analysis

An approach to reinforcement-schedule contingencies is presented that accommodates continuous as well as discrete effective dimensions of responses and reinforcers. College students' wheel turning was reinforced by projected reading material according to four schedule contingencies that incorporated either a discontinuous (count) or continuous (duration) dimension of the response and the reinforcer. The contingencies arranged a 1:1 correspondence between (a) response count and consequent stimulus count, (b) response duration and stimulus count, (c) response count and stimulus duration, and (d) response duration and stimulus duration. Contingencies incorporating response count produced moderate to high rates of very short-duration responses. Contingencies incorporating response duration produced very low-rate, long-duration responding. The dimension of the reinforcer had minimal or no additional effect. We suggest that incorporating duration and other continuous dimensions into schedule contingencies may improve our understanding of both laboratory and nonlaboratory behavior.     

Postconcussion Symptoms

Research pertaining to the self-report of symptoms after traumatic brain injury was reviewed. Cognitive, emotional, and motivational factors have more relevance than demographic (except for female sex) and personality factors. Specific neuropsychological deficits in attention and memory have been found in the early stages after head injury of even mild severity. This is unlikely to be the only factor affecting symptom persistence. Exaggeration of cognitive dysfunction occurs in some cases, but appears unrelated to symptom overreport. Increased emotional distress typically accompanies symptom persistence. The psychological reaction of preoccupation with symptoms and emotional distress is not unique to concussion, but also occurs after severe head injury and back injury and relates more to the personal interpretation of the effect of the trauma than to objective indicators of brain injury severity.     

科学研究的DNA共享与协作精神

股骨头坏死、髋关节脱位是骨科常见病,随着人们生活模式的改变发病率有所上升。对该病的成因、流行病学、病理转归、临床治疗策略与髋关节严重病损后功能重建等问题,学术界存在很大争议。作者提出从生物进化的角度、用自然重建理念做指导,应用髋关节分离牵拉术治疗股骨头坏死、骨盆补充截骨术重建青少年严重病损的髋关节功能人、组合性矫形手术治疗年长儿先天性髋关节脱位,获得了优良效果。因此呼吁:用自然重建理念治疗青少年股骨头坏死、髋关节脱位,降低人工假体置换对此类疾病的手术指证。     

Mild Head Injury in Children and Adolescents

Although mild head injury is the most prevalent type of head injury in children and adolescents, only a relatively small number of studies on this kind of head injury have been reported. This article summarizes a review of studies examining cognitive, academic, and psychosocial outcomes in children who sustained mild head injuries. Despite earlier claims of mild head injury being a "silent epidemic," the studies, which were published from 1970 to 1998, provide no compelling evidence to support this view.