Movement control in older adults: does old age mean middle of the road?

Old age is associated with poorer movement skill, as indexed by reduced speed and accuracy. Nevertheless, reductions in speed and accuracy can also reflect compensation as well as deficit. We used a manual tracing and a driving task to identify generalized spatial and temporal compensations and deficits associated with old age. In Experiment 1, participants used a hand-held stylus to trace a path. In Experiment 2, participants steered along paths in a virtual reality driving simulator. In both experiments, participants were required to stay within the boundaries while we manipulated task difficulty by changing path width or movement speed. The older group showed worse performance in the highly constrained conditions. Corner cutting effectively reduces the curvature of bends but yields a greater risk of error (i.e., clipping the path or road edge). Corner cutting is thus less risky on wider paths, and we found that corner cutting increased for both age groups in both tasks when paths were wider. Crucially, we observed a greater degree of corner cutting in the young group compared with the old, suggesting the old group compensated for decreased motor skill with "middle-of-the-road" behavior. Enforcing increased speed caused all participants to increase corner cutting. Thus, older participants showed spatial compensation for decreased skill by biasing their position toward the middle of the path in both a manual and steering task. External constraints (narrow paths and fast speeds) prevented this strategy and revealed age-related declines in skills central to manual control and driving.     

Tie my hands, tie my eyes

Previous studies have demonstrated that motor abilities allow us not only to execute our own actions and to predict their consequences, but also to predict others' actions and their consequences. But just how deeply are motor abilities implicated in action observation? If an observer is prevented from acting while witnessing others' actions, will this impact on their making sense of others' behavior? We recorded proactive eye movements while participants observed an actor grasping objects. The participants' hands were either freely resting on the table or tied behind their back. Proactivity of gaze behavior was dramatically impaired when participants observed others' actions with their hands tied. Since we don't literally perceive actions with our hands, the effect may be explained by the hypothesis that effective observation of action depends not only on motor abilities but on being in a position to exercise them. This suggests, for the first time, that actions are observed best when we are actually in the position to perform them.     

Belief in a just world, teacher justice, and bullying behavior

The relation between school students' belief in a just world (BJW) and their bullying behavior was investigated in a questionnaire study. The mediating role of teacher justice was also examined. Data were obtained from a total of N = 458 German and Indian high school students. Regression analyses revealed that the more strongly students believed in a personal just world and the more they evaluated their teachers' behavior toward them personally to be just, the less bullying behavior they reported. Moreover, students with a strong BJW tended to evaluate their teachers' behavior toward them personally to be more just, and the experience of teacher justice mediated the relation between BJW and less bullying perpetration. This pattern of results was as expected and consistent across different cultural contexts. It persisted when neuroticism, sex, and country were controlled. The adaptive functions of BJW and implications for future school research are discussed.     

Nonword repetition and phoneme elision in adults who do and do not stutter

The purpose of the present study was to explore the phonological working memory of adults who stutter through the use of a non-word repetition and a phoneme elision task. Participants were 14 adults who stutter (M=28 years) and 14 age/gender matched adults who do not stutter (M=28 years). For the non-word repetition task, the participants had to repeat a set of 12 non-words across four syllable lengths (2-, 3-, 4-, and 7-syllables) (N=48 total non-words). For the phoneme elision task, the participants repeated the same set of non-words at each syllable length, but with a designated target phoneme eliminated. Adults who stutter were significantly less accurate than adults who do not stutter in their initial attempts to produce the longest non-words (i.e., 7-syllable). Adults who stutter also required a significantly higher mean number of attempts to accurately produce 7-syllable non-words than adults who do not stutter. For the phoneme elision task, both groups demonstrated a significant reduction in accuracy as the non-words increased in length; however, there was no significant interaction between group and syllable length. Thus, although there appear to be advancements in the phonological working memory for adults who stutter relative to children who stutter, preliminary data from the present study suggest that the advancements may not be comparable to those demonstrated by adults who do not stutter. EDUCATIONAL OBJECTIVES: At the end of this activity the reader will be able to (a) summarize the nonword repetition data that have been published thus far with children and adults who stutter; (b) describe the subvocal rehearsal system, an aspect of the phonological working memory that is critical to nonword repetition accuracy; (c) employ an alternative means to explore the phonological working memory in adults who stutter, the phoneme elision task; and (d) discuss both phonological and motoric implications of deficits in the phonological working memory.     

Does simile comprehension differ from metaphor comprehension? A functional MRI study

Since Aristotle, people have believed that metaphors and similes express the same type of figurative meaning, despite the fact that they are expressed with different sentence patterns. In contrast, recent psycholinguistic models have suggested that metaphors and similes may promote different comprehension processes. In this study, we investigated the neural substrates involved in the comprehension of metaphor and simile using functional magnetic resonance imaging (fMRI) to evaluate whether simile comprehension differs from metaphor comprehension or not. In the metaphor and simile sentence conditions, higher activation was seen in the left inferior frontal gyrus. This result suggests that the activation in both metaphor and simile conditions indicates similar patterns in the left frontal region. The results also suggest that similes elicit higher levels of activation in the medial frontal region which might be related to inference processes, whereas metaphors elicit more right-sided prefrontal activation which might be related to figurative language comprehension.     

The locus of tool-transformation costs

Transformations of hand movements by tools such as levers or electronic input devices can invoke performance costs compared to untransformed movements. This study investigated by means of the Psychological Refractory Period (PRP) paradigm at which stage of information processing such tool-transformation costs arise. We used an inversion transformation, that is, the movement of the operating hand was transformed into a spatially incompatible movement of a lever. As a basic tool-transformation effect, the initiation of inverted tool movements was delayed compared to noninverted movements. Experiment 1 suggested a central (or postcentral) locus of this tool-transformation effect and ruled out a (precentral) perceptual locus. Experiments 2 and 3 confirmed the central locus and ruled out a later, motor-related stage of processing. The results show that spatially incompatible tool movements delay a capacity-limited stage of information processing, often referred to as response selection.     

The moderating role of empathy in the association between parental support and adolescent aggressive and delinquent behavior

The present two‐wave longitudinal study addressed the role of affective empathy and parental support in aggressive and delinquent behavior in a sample of 323 adolescents (158 boys, 165 girls). Self‐report questionnaires were used to assess affective empathy, perceived support from parents, delinquency, and aggression. Guided by theories on children's differential susceptibility to socialization, we expected adolescents with different levels of empathy to vary in their responsiveness to parental support. In agreement with our hypothesis, empathy moderated the relation of perceived parental support with aggressive and delinquent behavior. Controlling for the effect of gender and for the stability of aggression and delinquency, higher perceived parental support was predictive of lower levels of aggression at age 15, but only for adolescents high in empathy. Remarkably, adolescents low in empathy not only appeared to benefit less from parental support, but even showed more aggression and delinquency at age 15 when they perceived their parents to be more supportive at age 14. Aggr. Behav. 38:368‐377, 2012. © 2012 Wiley Periodicals, Inc.     

Priming the mental time line

Growing experimental evidence suggests that temporal events are represented on a mental time line, spatially oriented from left to right. Support for the spatial representation of time comes mostly from studies that have used spatially organized responses. Moreover, many of these studies did not avoid possible confounds attributable to target stimuli that simultaneously convey both spatial and temporal dimensions. Here we show that task-irrelevant, lateralized visuospatial primes affect auditory duration judgments. Responses to short durations were faster when the auditory target was paired with left- than with right-sided primes, whereas responses to long durations were faster when paired with right- than with left-sided primes. Thus, when the representations of physical space and time are concurrently activated, physical space may influence time even when a lateralized, spatially encoded response is not required by the task. The time-space interaction reported here cannot be ascribed to any Spatial-Temporal Association of Response Codes effect. It supports the hypothesis that the representation of time is spatially organized, with short durations represented on the left space and longer ones on the right.     

Eye movements blink the attentional blink

When presented with a sequence of visual stimuli in rapid succession, participants often fail to detect a second salient target, a phenomenon referred as the attentional blink (AB; Raymond, Shapiro, & Arnell, 1992; Shapiro, Raymond, & Arnell, 1997). On the basis of a vast corpus of experiments, several cognitive theories suggest that the blink results from a discrete structuring of attention, sampling information from temporal episodes during which several items can access encoding process (Wyble, Bowman, & Nieuwenstein, 2009; Wyble, Potter, Bowman, & Nieuwenstein, 2011). The objective of this work is to explore the AB when multiple items are presented at the fovea during ocular movements. The authors reasoned that each fixation may cohesively form an episode and hence expected that the blink may vanish within a single fixation. In turn, they expected saccades to accentuate episodic borders and hence shorten the regime of interference when 2 targets are presented fovealy in successive fixations. Evidence is provided in favor of this hypothesis, showing that the blink vanishes when both targets are presented in the core of a single fixation (far from the saccadic boundaries) and that it recovers more rapidly in successive fixations. These studies support current views that episodes should have an effect on the AB and provide evidence that eye movements play an important role in the formation of episodes.     

Structural salience and the nonaccidentality of a gestalt

We perceive structure through a process of perceptual organization. Here we report a new perceptual organization phenomenon-the facilitation of visual grouping by global curvature. Observers viewed patterns that they perceived as organized into collections of curves. The patterns were perceptually ambiguous such that the perceived orientation of the patterns varied from trial to trial. When patterns were sufficiently dense and proximity was equated for the predominant perceptual alternatives, observers tended to perceive the organization with the greatest curvature. This effect is tantamount to visual grouping by maximal curvature and thus demonstrates an unprecedented effect of global structure on perceptual organization. We account for this result with a model that predicts the perceived organization of a pattern as function of its nonaccidentality, which we define as the probability that it could have occurred by chance. Our findings demonstrate a novel relationship between the geometry of a pattern and the visual salience of global structure.