Making a Task Difficult: Evidence That Device-Oriented Steps Are Effortful and Error-Prone

Errors in the execution of procedural tasks can have severe consequences. Attempts to ameliorate these slip errors through increased training and motivation have been shown to be ineffective. Instead, we identified the steps in a task procedure on which errors are most likely to occur, so that these might be designed out of the task procedure in the first place. Specifically, we considered whether device-oriented steps (i.e., steps in the task procedure that do not directly contribute to the achievement of the task goal) are more error-prone than task-oriented steps (i.e., steps that do directly contribute to the task goal). Two experiments are reported in which participants were trained to perform a novel procedural task. Across conditions, we manipulated the extent to which each step in the task procedure appeared to contribute to the achievement of the task goal (i.e., alternating the assignment of a task step between device- and task-oriented), while keeping the interface and underlying task procedure the same. Results show that participants made more errors and took longer to complete a task step when it played a device-oriented role rather than a task-orientated role. These effects were exacerbated by the introduction of a secondary task designed to increase working memory load, suggesting that when a task step plays a device-oriented role it is more weakly represented in memory. We conclude that device-oriented task steps are inherently problematic and should be avoided where possible in the design of task procedures

Investigating the Role of Executive Processes in Young Children's Prospective Memory

Prospective memory (PM) is the ability to remember to carry out one's intentions. This is a critical ability for children to develop in order to function independently in their daily activities. This dissertation examines the role of executive functioning in preschoolers' PM in two studies that vary the executive demand at different stages of the PM task. Study 1 investigated the role of task difficulty during the retention interval prior to the PM task. A difficult working memory task during the delay period resulted in worse PM performance in 4- and 5-year-olds compared to an easy working memory task. In addition, children's working memory, planning ability, and theory of mind correlated with PM but only in the difficult filler task condition. Study 2 examined age differences between 4- and 5-year-olds in PM task performance when the task: (1) was embedded in an easy or difficult ongoing task, (2) had an instruction to focus on the intention versus an instruction to focus on the distractor activity during the retention interval, and (3) varied in the salience of prospective targets. Overall, 5-year-olds performed better on the PM task than 4-year-olds. Children also had superior PM when targets were salient compared to non-salient and marginally superior PM when they received an instruction to monitor their intention compared to when they received an instruction to focus on the distractor activity. In addition, positive relations between executive functioning and PM were documented. Taken together, these studies suggest that disrupting or encouraging monitoring has a direct impact on PM performance in certain conditions. The implications of these results for theories that suggest differing roles for controlled processes in PM are discussed

Visual motion processing and human tracking behavior

The accurate visual tracking of a moving object is a human fundamental skill that allows to reduce the relative slip and instability of the object's image on the retina, thus granting a stable, high-quality vision. In order to optimize tracking performance across time, a quick estimate of the object's global motion properties needs to be fed to the oculomotor system and dynamically updated. Concurrently, performance can be greatly improved in terms of latency and accuracy by taking into account predictive cues, especially under variable conditions of visibility and in presence of ambiguous retinal information. Here, we review several recent studies focusing on the integration of retinal and extra-retinal information for the control of human smooth pursuit.By dynamically probing the tracking performance with well established paradigms in the visual perception and oculomotor literature we provide the basis to test theoretical hypotheses within the framework of dynamic probabilistic inference. We will in particular present the applications of these results in light of state-of-the-art computer vision algorithms

Eye and hand movements disrupt attentional control

Voluntary attentional control is the ability to selectively focus on a subset of visual information in the presence of other competing stimuli–a marker of cognitive control enabling flexible, goal-driven behavior. To test its robustness, we contrasted attentional control with the most common source of attentional orienting in daily life: attention shifts prior to goal-directed eye and hand movements. In a multi-tasking paradigm, human participants attended at a location while planning eye or hand movements elsewhere. Voluntary attentional control suffered with every simultaneous action plan, even under reduced task difficulty and memory load–factors known to interfere with attentional control. Furthermore, the performance cost was limited to voluntary attention: We observed simultaneous attention benefits at two movement targets without attentional competition between them. This demonstrates that the visual system allows for the concurrent representation of multiple attentional foci. Since attentional control is extremely fragile and dominated by premotor attention shifts, we propose that action-driven selection plays the superordinate role for visual selection