Task Difficulty

ABSTRACT This study investigated how the degree of task difficulty, operationalized as the existence of a loose or tight storyline structure, affects self-repair behavior in L2 oral speech. Thirty Iranian female lower-intermediate EFL learners performed two oral narrative tasks, with loose and tight storyline structures. Then, they listened to the audio-tapes of their own performances and were asked to report their thoughts at the time they were performing the task, retrospectively. Results of the analyses revealed that there is a relationship between task difficulty and self-repair behavior such that with the difficult task, participants mostly effectuated appropriacy and different-information repairs. However the participants who performed the less difficult task were predominantly concerned with rectifying their ungrammatical or lexically inappropriate utterances and therefore executed error-repairs more frequently.

No theory of driver behaviour has yet managed to achieve widespread acceptance and use in the field of Traffic Psychology, partly due to the difficulty in testing many of the theories. However, one class of theories, the motivational theories, can be usefully split into two groups and the differences between them can then be examined. One group posits the constant monitoring and targeting of a certain subjective variable, often risk, as the controlling factor in driving. The other group however states that subjective variables such as risk are only relevant once a certain threshold has been passed.In this study we aimed to examine this difference by manipulating both speed of travel and the amount of cognitive load participants were under. Participants were asked to initially drive at their preferred speed for 1 min in a driving simulator. Participant's speed was then automatically increased or decreased by 10, 20 30 km/h or left unchanged. Participants were then required to maintain the new speed for 1 min. After this 1 min the speed was again automatically changed and had to be maintained for one more minute, but this time participants also carried out a secondary mental arithmetic task. Finally participants were asked to again drive for another 1 min at their preferred speed. This procedure was repeated seven times, once for each speed manipulation; −30, −20, −10, +0, +10, +20 and +30 km/h. After each 1 min interval verbal ratings of task difficulty, effort, feeling of risk and the typicality of the speed were collected.The results show a threshold effect in ratings of task difficulty, effort and feeling of risk, with no significant difference given between the ratings during the baseline period and the experimentally decreased speed periods until after participant's preferred speed of travel had been exceeded. Furthermore, even when under cognitive load the threshold relationship was still apparent, if diminished. Finally it appears that when under cognitive load drivers have difficulty maintaining a travelling speed which is lower than the speed at which they would prefer to drive. However, driving at a speed in excess of their preferred speed appears to be easier to maintain, at least in the short term.► Examines the constant risk/feeling monitoring and threshold accounts of driving. ► Finds support for the threshold account. ► Threshold is crossed when participants first go faster than they would freely choose. ► Threshold perception persists under external cognitive load.

Measures of private speech and task performance were obtained for a sample of 46 5- and 6-year-olds engaged on a mechanical version of the Tower of London (ToL) task. Two different sets of four puzzles of increasing difficulty were attempted on two occasions. In line with Vygotskian predictions, there was a quadratic relation between private speech and task difficulty, but no evidence of a shift towards self-regulatory sub-types of private speech with increasing task difficulty. Levels of self-regulatory private speech were significantly related to concurrent, but not subsequent, task performance. We discuss the significance of these findings for the Vygotskian view that private speech has an adaptive function in the self-regulation of behaviour.

This study aims to determine the difficulties that middle school mathematics teachers have in teaching integers, the analogies they use to solve these difficulties, and the efficiency of these analogies. The study was conducted with 10 mathematics teachers, 6 females and 4 males, who were working in middle schools affiliated with the Ministry of National Education (MNE), selected using the convenience sampling method. The study used the case study design among the qualitative research methods. The data were collected using open-ended questions and analyzed using descriptive and content analysis. The findings were presented under three categories which are the difficulties they have in teaching integers, the curriculum on the subject of integers, and the analogies found in textbooks or used by teachers and their efficiency. Recommendations were made based on these findings. Centralized Early Childhood Development Policy of the early childhood education.

Robotic surgery technology has made significant advances recently in a wide range of clinical applications. Despite the documented benefits of robotic-assisted surgery, the main limitation is that procedures take more time than traditional manual techniques. Human factors engineering will play a pivotal role in designing a surgeon-robot interface that can optimize the surgeon's performance to minimize such drawbacks. The Zeus surgical robot was used to perform a Fitts' aimed movement task with 10 subjects to determine the ...

The brain is probably the most interesting example of a complex network having 1/f1/f variability as determined through the analysis of EEG time series and magnetoencephalogram recordings. Herein we develop a theory of 1/f1/f noise of human cognition to explain the recent experimental observations that increasing the difficultly of cognitive tasks accelerates the transition from observed 1/f1/f noise to white noise in decision-making time series.

During postural and locomotor tasks, the orientation of the head with respect to space is maintained in order to serve as an egocentric reference value for maintaining balance. In young children during locomotor tasks, task difficulty determines the coordination of movements between head-trunk segments: the more difficult the task, the more the child limits the head on trunk movement ("en bloc") rather than letting the head move freely in space. For reaching tasks, however, there are no data about the development and maturation of coordination between the head and trunk movements and when the pattern of coordination is considered mature. The goal of this study was to characterize the development of head-trunk coordination during reaching from a sitting position in typically developing children. Forty-four typically-developing (TD) children aged from 2.8 to 11.8 years and six healthy adults participated. Children were divided into five groups (G1-G5) according to their age: 2-3, 4-5, 6-7, 8-9 and 10-11 years old. The task involved reaching towards and grasping a piece of food in the younger group or a wooden block in the older children and adults with the dominant hand, adequate to the grip size of each participant, and returning it to the mouth area to simulate self-feeding. The object was placed in line with the midline of the body at three different distances from the trunk according to the participant's arm length (two within and one beyond arm's length). Rotational movements of the head and trunk in three planes; yaw, roll and pitch, were recorded using three-dimensional tracking systems (Optotrak, Northern Digital, Model 3010 or Ariel Performance Analysis System). The variables analysed were relative head and trunk angle, absolute head and trunk angle, the anchoring index (AI) and initial direction of head and trunk rotation (direction index: DI). Patterns of head-trunk coupling were different along different axes of rotation and across groups. For the AI, a head-stabilized-on-trunk (HST) or "en bloc" pattern was observed with approximately the same frequency as a head-stabilized-in-space (HSS) pattern in the youngest children in the yaw plane for reaches within arm's length. In all other planes and for reaches of all distances, a HSS pattern was evident in the youngest children and remained consistent across the groups of children. Compared to the children, adult reaching was characterised by fixed head-trunk coordination (HST) in the roll plane at all reach distances, and greater decoupling in yaw plane motion for the two closest distances. There were no age-related differences in the pitch plane strategy which was mainly HSS. The DI patterns matured by 2-3 or 4-5 years of age, except for reaches to T1 in the pitch plane. In addition, in the roll plane, there was evidence of a two-step maturation that was not complete until adulthood. Maturation of strategies used to stabilize the head and trunk relative to each other and to the reaching arm differ across movement planes for a seated reaching task. Our data suggest that different aspects of head and trunk coordination during reaching movement mature at different rates, like for locomotor tasks previously described, and that the maturation follows a non-chronological and protracted course. These results can serve as a comparative database with which to contrast head and trunk coordination in children with movement disorders. However, in terms of typical development, these data should be considered specific for the task studied and may not reflect general principles of motor development.

We report results from a dual electroencephalography (EEG) study, in which two-member teams performed a simulated combat scenario. Our aim was to distinguish expert from novice teams by their brain dynamics. Our findings suggest that dimensionality increases in the joint brain dynamics of the team members is a signature of increased task demand, both objective, e.g. increased task difficulty, and subjective, e.g. lack of experience in performing the task. Furthermore in each team we identified a subspace of joint brain dynamics related to team coordination. Our approach identifies signatures specific to team coordination by introducing surrogate team data as a baseline for joint brain dynamics without team coordination. This revealed that team coordination affects the subspace itself in which the joint brain dynamics of the team members are evolving, but not its dimensionality. Our results confirm the possibility to identify signatures of team coordination from the team members’ brain dynamics.