The broken heart phenomenon: An examination of the mortality of bereavement

Bereaved people are at greater risk of losing their lives than the non-bereaved. This paper explores the evidence on this ‘bereavement—mortality relationship’, to establish who among the bereaved are most vulnerable to such dire consequences of loss. Information is drawn from several sources, including epidemiological research on sociodemographic variables, analyses of causes of death and recent empirical studies that have identified differences between bereaved decedents and survivors. The survey shows that risk factors interact in complex ways to determine level of vulnerability. A simple explanation in terms of ‘broken heart’ cannot account for the pattern of results. Some bereaved subgroups are more vulnerable to death than others, excess risk occurs across a variety of causes of death (suggesting different underlying processes), and personal characteristics in combination with circumstantial factors lead to high vulnerability. It is concluded that two types of process underlie the bereavement–mortality relationship. These are related: (a) to the direct effects of grief (broken heart); and (b) to secondary consequences associated with the stress of bereavement.     

Practice and assimilation effects in a multilimb aiming task

When two limbs are required to move different distances simultaneously, assimilation effects are shown: The shorter distance limb tends to overshoot the target, whereas the longer distance limb undershoots. The effect of practice on assimilation effects was studied in two experiments, using a simultaneous four-limb aiming task. When subjects were required to move their left limbs a shorter distance than the right (5 cm vs. 9 cm), the right limbs moved a lesser distance and had greater variable and overall errors relative to a group required to move all limbs the same distance (9 cm). Practice reduced assimilation effects in the lower limbs, but spatial assimilations were present throughout 125 acquisition trials with KR and 50 no-KR transfer trials, spanning 24 hours. When the upper limbs were required to move a greater distance than the lower limbs (15 cm vs. 9 cm), the lower limbs showed longer distances and increased overall errors early in practice compared to the lower limbs of a group required to move all limbs 9 cm. With practice, the between-group differences decreased, with no assimilation effects shown on the transfer trials. The results suggest that neural crosstalk is greater between left and right sides than between upper and lower limbs. Results are discussed in light of the functional cerebral space model of simultaneous actions.     

Practice and Assimilation Effects in a Multilimb Aiming Task

When two limbs are required to move different distances simultaneously, assimilation effects are shown: The shorter distance limb tends to overshoot the target, whereas the longer distance limb undershoots. The effect of practice on assimilation effects was studied in two experiments, using a simultaneous four-limb aiming task. When subjects were required to move their left limbs a shorter distance than the right (5 cm vs. 9 cm), the right limbs moved a lesser distance and had greater variable and overall errors relative to a group required to move all limbs the same distance (9 cm). Practice reduced assimilation effects in the lower limbs, but spatial assimilations were present throughout 125 acquisition trials with KR and 50 no-KR transfer trials, spanning 24 hours. When the upper limbs were required to move a greater distance than the lower limbs (15 cm vs. 9 cm), the lower limbs showed longer distances and increased overall errors early in practice compared to the lower limbs of a group required to move all limbs 9 cm. With practice, the between-group differences decreased, with no assimilation effects shown on the transfer trials. The results suggest that neural crosstalk is greater between left and right sides than between upper and lower limbs. Results are discussed in light of the functional cerebral space model of simultaneous actions.     

The influence of asymmetric force requirements on a multi-frequency bimanual coordination task

An experiment was designed to determine the impact of the force requirements on the production of bimanual 1:2 coordination patterns requiring the same (symmetric) or different (asymmetric) forces when Lissajous displays and goal templates are provided. The Lissajous displays have been shown to minimize the influence of attentional and perceptual constraints allowing constraints related to neural crosstalk to be more clearly observed. Participants (N = 20) were randomly assigned to a force condition in which the left or right limb was required to produce more force than the contralateral limb. In each condition participants were required to rhythmically coordinate the pattern of isometric forces in a 1:2 coordination pattern. Participant performed 13 practice trials and 1 test trial per force level. The results indicated that participants were able to effectively coordinate the 1:2 multi-frequency goal patterns under both symmetric and asymmetric force requirements. However, consistent distortions in the force and force velocity time series were observed for one limb that appeared to be associated with the production of force in the contralateral limb. Distortions in the force produced by the left limb occurred regardless of the force requirements of the task (symmetric, asymmetric) or whether the left or right limb had to produce more force than the contralateral limb. However, distinct distortions in the right limb occurred only when the left limb was required to produce 5 times more force than the right limb. These results are consistent with the notion that neural crosstalk can influence both limbs, but may manifest differently for each limb depending on the force requirements of the task.     

Limb-specific emotional modulation of cervical spinal cord neurons

Emotional stimuli receive prioritized attentional and motoric processing in the brain. Recent data have indicated that emotional stimuli enhance activity in the cervical spinal cord as well. In the present study, we used fMRI to investigate the specificity of this emotion-dependent spinal cord activity. We examined whether the limb depicted in a passively viewed image (upper vs. lower) differentially influenced activity in the cervical segments that innervate the upper limbs, and whether this effect was enhanced by emotion. Participants completed four fMRI runs: neutral–upper limb, neutral–lower limb, negative–upper limb, and negative–lower limb. The results indicated main effects of limb and emotion, with upper limbs and negative stimuli eliciting greater activity than lower limbs and neutral stimuli, respectively. For upper-limb runs, negative stimuli evoked more activity than did neutral stimuli. Additionally, negative stimuli depicting upper limbs produced stronger responses than did negative stimuli depicting lower limbs. These results suggest that emotional stimuli augment limb-specific responses in the spinal cord.     

Limb Dominance and Its Effects on the Benefits of Intralimb Transfer of Learning: A Visuomotor Aiming Task

Research has attempted to address what characteristics benefit from transfer of learning; however, it is still unclear which characteristics are effector dependent or independent. Furthermore, it is not clear if intralimb transfer shows, similarly to interlimb transfer, an asymmetry of benefits between the upper limbs. The purpose of the current study is to examine if effector independence effects emerge, as observed in interlimb transfer studies, when transfer to new effector group within the same limb occurs, and whether the pattern of intralimb transfer benefits differ between the limbs. Our results suggest that a visuomotor task transfers within both limbs, even though the transfer benefits within the limbs seem to differ. This was supported by more transfer occurring in the dominant limb than the nondominant limb. Potential control mechanisms used for intralimb transfer are discussed.     

Intralimb gait coordination of individuals with stroke using vector coding

Individuals with stroke often present functional impairment and gait alteration. Among different aspects, intralimb coordination of these individuals is one of the key points that should be considered before implementing any gait intervention protocol. The purpose of this study was to investigate the effects of stroke on intralimb gait coordination of the lower limbs using a vector coding technique. Twenty-five individuals with stroke and 18 non-disabled individuals (control), between 46 and 71 years old, participated in this study. A computerized analysis system registered data from reflective markers placed on specific body landmarks to define thigh, shank, and foot of both body sides, as participants walked at self-selected comfortable speed. Coordination modes, such as in-phase, anti-phase, proximal-segment-phase, and distal-segment-phase, and variability of thigh-shank, and shank-foot were analyzed for the paretic, non-paretic and control limbs during the stance and swing periods, and the entire gait cycle using the vector coding technique. During the stance period, individuals with stroke presented higher frequency of thigh-phase and lower frequency of shank-phase for the thigh-shank coupling and higher frequency of shank-phase for the shank-foot coupling compared to non-disabled controls, indicating that the proximal segment of each pair leads the movement. During the swing period, the paretic limb presented higher frequency for in-phase than non-paretic and control limbs for the thigh-shank coupling. Adaptations in the non-paretic limb were observed in the swing period, with higher frequency than paretic and control limbs in the thigh-phase for the thigh-shank coupling, and higher frequency than the paretic limb in the foot-phase for the shank-foot coupling. No differences in coordination variability were found between paretic, non-paretic, and control limbs. The vector coding technique constitutes a useful tool for identifying gait alterations in intralimb coordination of individuals with stroke. Our coordination results demonstrate a shift from distal to more proximal control during the stance phase in both legs for the individuals with stroke and an inability to decouple segment coordination during the swing phase in the paretic limb. The results indicate that it is more suitable to consider the stance and swing periods separately instead of considering the entire gait cycle to investigate intralimb gait coordination of individuals with stroke.     

Sequential aiming with one and two limbs: Effects of target size

It is well reported that movement times to the first target in a two-target sequence are slower than when a single target response is required. This one-target advantage has been shown to emerge when the two-target sequence is performed with the same limb and when the first and second segments within the sequence are performed with different limbs (i.e., when there is a switch between limbs at the first target). The present study examined the functional dependency between response segments in both single and two limb sequential aiming by varying the accuracy demands at the first and second target. Results revealed that, for both one and two limb conditions, the one-target advantage was present with large first targets but not with small first targets. Additionally, when the first target was large and the second target was small, spatial variability at the first target was significantly less (or constrained more) in both one and two limb conditions compared to conditions requiring only a single target response. These findings suggest that similar principles underlie the one-target advantage in both single and two limb sequential movements.     

Self-reported physical aggression among young men

This article describes two studies involving a questionnaire asking about the circumstances, antecedents, and consequences of the most recent fight among samples of young men (100 students in Study I; 88 students and 87 unemployed men in Study II). In Study I, the students alos completed a standard aggression questionnaire and one concerning masculine values to assess whether measures of physical aggressiveness were associated with traditional masculine role norms. There was a weak association with physical aggressiveness but not with reported fights. Students with traditionally masculine interests did report more fights. In Study II, both subsamples showed significant correlations between a masculine role subscale involving toughness from this study were primarily assessed in relation to hyphotheses derived from Darwinian sexual selection theory: that fights between young men are likely to arise from threats to personal integrity and status, women, and resoureces; that fights will be more related to social status and be more damageing among the unemployed men than the students. In line with these predictions, insults were a potent cause of fights in both samples, but public humiliation was a more common reason among the unemployed men, Money or property was more often a reason for fighting among the unemployed men also showed higher levels of anger and physical aggression (but not verbal aggression) on a standard aggression questionnaire. Other differences included the location of the fight, but there were no significant differences between the two samples in whether or not a fight had occured in the last 5 years. © 1995 Wiley-Liss, Inc.     

The role of proprioception in action recognition

This study aimed at evaluating the role of proprioception in the process of matching the final position of one's limbs with an intentional movement. Two experiments were realised with the same paradigm of conscious recognition of one's own limb position from a distorted position. In the first experiment, 22 healthy subjects performed the task in an active and in a passive condition. In the latter condition, proprioception was the only available information since the central signals related to the motor command were likely to be absent. The second experiment was realised with a deafferented patient who suffers from a complete haptic deafferentation, including loss of proprioception. The results first argue in favour of a dominant role of proprioception in action recognition, but they also stress the possible role of central signals. The process of matching the final position of one's limbs with an intended movement and thus of action recognition would be achieved through a comparison process between the predicted sensory consequences of the action, which are stored in its internal model, and the actual sensory consequences of that action.     

Why some women can feel more,and others less,attractive after exposure to attractive targets: The role of social comparison orientation

As the tendency to compare oneself with others may be associated with the tendency to focus on similarities, we hypothesized that individual differences in social comparison orientation (SCO) may moderate the consequences of upward and downward comparisons. In Study 1, high comparers were found to focus more on similarities than low comparers, suggesting that high comparers are more likely to assimilate in general. In Study 2, SCO was found to be positively associated with mood following exposure to an attractive target, and negatively associated with mood following exposure to a less attractive target. In Studies 2 and 3, SCO was found to be positively associated with self‐evaluations of attractiveness following exposure to an attractive target and negatively associated with self‐evaluations of attractiveness following exposure to a less attractive target. These results indicate that research on the consequences of social comparison must attend to individual differences in SCO. Copyright © 2009 John Wiley & Sons, Ltd.     

Postural asymmetries in response to holding evenly and unevenly distributed loads during self-selected stance

The authors examined postural asymmetries during quiet stance and while holding evenly or unevenly distributed loads. Right-hand dominant subjects preferentially loaded their right lower limb when holding no load or a load evenly distributed in both hands, but no differences in center of pressure (CoP) were observed between the left and right limbs. However, longer CoP displacement was observed under the preferentially loaded limb, which may reflect a functional asymmetry that allows quick movement of one limb in response to a potential perturbation. When a load was held only in the nondominant hand, sample entropy decreased in the left (loaded) limb but increased in the right (unloaded) limb, suggesting the unloaded foot compensated for a loss of control flexibility in the loaded foot.     

Postural Asymmetries in Response to Holding Evenly and Unevenly Distributed Loads During Self-Selected Stance

The authors examined postural asymmetries during quiet stance and while holding evenly or unevenly distributed loads. Right-hand dominant subjects preferentially loaded their right lower limb when holding no load or a load evenly distributed in both hands, but no differences in center of pressure (CoP) were observed between the left and right limbs. However, longer CoP displacement was observed under the preferentially loaded limb, which may reflect a functional asymmetry that allows quick movement of one limb in response to a potential perturbation. When a load was held only in the nondominant hand, sample entropy decreased in the left (loaded) limb but increased in the right (unloaded) limb, suggesting the unloaded foot compensated for a loss of control flexibility in the loaded foot.     

Laterally focused attention modulates asymmetric coupling in rhythmic interlimb coordination

Peters (J Motor Behav 21:151-155, 1989; Interlimb coordination: neural, dynamical and cognitive constraints, Academic, Orlando, pp 595-615, 1994) suggested that expressions of handedness in bimanual coordination may be reflections of an inherent attentional bias. Indeed, previous results indicated that focusing attention on one of the limbs affected the relative phasing between the limbs in a manner comparable to the effects of hand dominance. The present study extended the comparison between the effects of attentional focus and handedness by testing their impact on the interactions between the limbs. Both left-handed and right-handed participants performed rhythmic bimanual coordination tasks (in-phase and antiphase coordination), while directing attention to either limb. Using brief mechanical perturbations, the degree to which the limbs were influenced by each other was determined. The results revealed that the non-dominant limb was more strongly affected by the dominant limb than vice versa and that, in line with Peters' proposition, this handedness-related asymmetry in coupling strength was reduced when attention was focused on the non-dominant limb, thereby highlighting the potential relation between inherent (handedness-related) asymmetries and voluntary attentional asymmetries. In contrast to previous findings, the (commonly observed) phase lead of the dominant limb was attenuated (rather than accrued) when attention was focused on this limb. This unexpected result was explained in terms of the observed attention-related difference in amplitude between the limbs.     

The effect of limb crossing and limb congruency on multisensory integration in peripersonal space for the upper and lower extremities

The present study investigated how multisensory integration in peripersonal space is modulated by limb posture (i.e. whether the limbs are crossed or uncrossed) and limb congruency (i.e. whether the observed body part matches the actual position of one’s limb). This was done separately for the upper limbs (Experiment 1) and the lower limbs (Experiment 2). The crossmodal congruency task was used to measure peripersonal space integration for the hands and the feet. It was found that the peripersonal space representation for the hands but not for the feet is dynamically updated based on both limb posture and limb congruency. Together these findings show how dynamic cues from vision, proprioception, and touch are integrated in peripersonal limb space and highlight fundamental differences in the way in which peripersonal space is represented for the upper and lower extremity.     

Other- versus self-focus and risky health behavior: the case of HIV/AIDS

We examined the relationships of other-focus and self-focus with risky health behaviors among HIV+ individuals. Participants who were recruited by an AIDS advocacy organization completed anonymous questionnaires that included measures of other-focus (i.e. empathic concern and perspective-taking) and self-focus (i.e. personal distress and exaggerated internal control); direct measures of concern about the consequences of HIV/AIDS for the self, close others, and society; and a measure of willingness to engage in HIV/AIDS risk behaviors. As predicted, other-focus measures were generally associated with less, and self-focus measures with greater, willingness to engage in risky behavior. However, concern about the consequences of HIV/AIDS for close others was similar to self-focus and was associated with greater willingness to engage in risky behavior. These results are consistent with the notion that prevention efforts focusing on the consequences of HIV/AIDS – and perhaps other communicable diseases – might be more effective if they highlighted the consequences of the disease for society.     

Motor prediction at the edge of instability: alteration of grip force control during changes in bimanual coordination

Predicting the consequences of actions is fundamental for skilled motor behavior. We investigated whether motor prediction is influenced by the fact that some movements are easier to perform and stabilize than others. Twelve subjects performed a bimanual rhythmical task either symmetrically or asymmetrically (the latter being more difficult and less stable) while oscillating in each hand an object attached to an elastic cord. Motor prediction was monitored through the adequacy of anticipatory grip force adjustments with respect to the elastic resisting force. Results showed less adequate predictive control during asymmetrical movements (compared with symmetrical ones). Furthermore, switching between modes of coordination induced even larger alterations. An interesting finding was that grip force control did not always stabilize around the expected value after voluntary transition. We conclude that motor prediction is affected by the degree of coordination between the upper limbs and by phase transitions and is prone to carryover effects.     

Inter-limb coupling in individuals with transtibial amputation during bilateral stance is direction dependent

We investigated the control of upright standing in individuals with unilateral transtibial amputation (TTA) by assessing the inter-limb coupling and the coupling between the center of pressure beneath both limbs combined (COP_NET) and the center of pressure (COP) beneath the prosthetic limb and the intact limb. Twenty-one adults with TTA and eighteen unimpaired adults completed 90 s of standing on two parallel force plates. The inter-limb coupling and the coupling between the COP beneath each limb and the COP_NET were assessed by quantifying the synchronization of the COP signals. This included the number of epochs with synchronized signals, the total duration of signal synchronization and the relative phase and deviation phase between the signals. Additionally, magnitude and temporal characteristics of the COP displacements were quantified. Individuals with TTA exhibited looser inter-limb coupling in the anterior-posterior direction, characterized by more shifts between epochs with synchronized signals, shorter total duration of signal synchronization, less in-phase coordination patterns and a higher deviation phase between the two limbs, compared to unimpaired individuals. This coincided with a larger and more irregular postural sway in the TTA group. No group difference was observed in the mediolateral direction. The coupling between the COP_NET and the COP beneath the individual limbs was similarly direction dependent, and tighter for the intact side, suggesting that an intact limb-driven strategy was utilized.     

Isofrequency and Multifrequency: Coordination Patterns as a Function of the Planes of Motion

A series of studies examine the maintenance of the relative phase of simultaneous cyclic limb movements by the manipulation of the planes of motion during isofrequency and multifrequency conditions. To evaluate predictions from a dynamic pattern approach in which differences in the limbs' uncoupled frequencies give way to competitive interactions when the limbs are moved simultaneously, Experiment 1 determined the preferred frequencies of single-limb movements during sagittal and transverse planes of motions. The results revealed that the plane in which the motion was produced significantly affected the cycle frequencies. In investigating isofrequency coordination, Experiment 2 showed that homologous limbs were more accurate in attaining the relative phasing when moving in one as compared to two separate planes, whereas no such effect was observed for non-homologous limbs. Furthermore, the planes of motion significantly influenced the variability of relative phasing such thattwo-plane motionswere less stable than one-plane motions.Experiment 3 examined the effect of the planes of motion upon multifrequency coordination and demonstrated that the homologous and homolateral limbs were less successful in producing the relative phasing when the motions were produced in one as compared to two planes, whereas this effect was not observed for the heterolateral limbs. These findings indicate that frequency detuning resulting from the planes manipulation affects the quality of phase-locking during isofrequency and multifrequency conditions, even though it may be assumed that additional neural constraints are involved in the interlimb coordination process.     

The Social Construction of Injustice: Fairness Judgments in Response to Own and Others' Unfair Treatment by Authorities

The research literature in organizational justice has examined in some detail the dynamics and consequences of justice judgments based on direct experiences with fair and unfair authorities, but little is known about how people form justice judgments on the basis of reports of injustice by others or how group discussion changes justice judgments. The present study examined the consequences of distributed injustice, in which all members of a group experience some denial of voice, and concentrated injustice, in which one member experiences repeated denial of voice and others do not. It was predicted and found that mild personal experiences of injustice are a more potent source of group impressions of injustice than are reports of more severe injustice experienced by others. In both conditions, group ratings of unfairness were more extreme than were the mean of individual ratings either before or after discussion.