A Neural Model for Context-dependent Sequence Learning

A novel neural network model is described that implements context-dependent learning of complex sequences. The model utilises leaky integrate-and-fire neurons to extract timing information from its input and modifies its weights using a learning rule with synaptic noise. Learning and recall phases are seamlessly integrated so that the network can gradually shift from learning to predicting its input. Experimental results using data from the real-world problem domain demonstrate that the use of context has three important benefits: (a) it prevents catastrophic interference during learning of multiple overlapping sequences, (b) it enables the completion of sequences from missing or noisy patterns, and (c) it provides a mechanism to selectively explore the space of learned sequences during free recall.     

Motion extrapolation of auditory–visual targets

Many tasks involve the precise estimation of speed and position of moving objects, for instance to catch or avoid objects that cohabit in our environment. Many of these objects are characterised by signal representations in more than one modality, such as hearing and vision. The aim of this study was to investigate the extent to which the simultaneous presentation of auditory and visual signals enhances the estimation of motion speed and instantaneous position. Observers are asked to estimate the instant when a moving object arrives at a target spatial position by pressing a response button. This task requires observers to estimate the speed of the moving object and to calibrate the timing of their manual response such that it coincides with the true arrival time of the moving object. When both visual and auditory motion signals are available, the variability in estimating the arrival time of the moving object is significantly reduced compared to the variability in the unimodal conditions. This reduction in variability is consistent with optimal integration of the auditory and visual speed signals. The average bias in the estimated arrival times depends on the motion speed: for medium speeds (17 deg/s) observers’ subjective arrival times are earlier than the true arrival times; for high speeds (47 deg/s) observers exhibit a (much smaller) bias in the other direction. This speed-dependency suggests that the bias is due to an error in estimating the motion speeds rather than an error in calibrating the timing of the motor response. Finally, in this temporal localization task, the bias and variability show similar patterns for motion defined by vision, audition or both.     

Some methodological deficiencies in studies on traffic accident predictors

The paper discusses some methodological problems in (psychological) research on traffic accident predictors and reviews a convenience sample of the literature. Three methodological aspects are identified as being important: reliability of accident predictors, time period for accidents used as dependent variable, and culpability for accidents. Papers are scrutinized and most are found to be wanting in these aspects. Traffic researchers do not adhere to, or hardly even discuss, these basic methodological problems. It is concluded that the current research into (psychological) accident predictors is fraught with methodological deficiencies. Why most studies seem to be deficient in these aspects is not clear, as several researchers have pointed out these problems.     

A direct link between gaze perception and social attention.

How information is exchanged between the cognitive mechanisms responsible for gaze perception and social attention is unclear. These systems could be independent; the “gaze cueing” effect could emerge from the activation of a general-purpose attentional mechanism that is ignorant of the social nature of the gaze cue. Alternatively, orienting to social gaze direction might be directly determined by the operation of cognitive mechanisms specifically dedicated to gaze perception. This second notion is the dominant assumption in the literature, but there is little direct support for this account. Here, we systematically manipulated observers' perception of gaze direction by implementing a gaze adaptation paradigm. Gaze cueing was reduced only in conditions where perception of specific averted gaze stimuli was impaired (Experiment 1). Adaptation to a pointing stimulus failed to impact gaze cueing (Experiment 2). Overall, these data suggest a direct link between the specific operation of gaze perception mechanisms and the consequential orienting of attention. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The use of force feedback and auditory cues for performance of an assembly task in an immersive virtual environment

Using an immersive virtual environment, this study investigated whether the inclusion of force feedback or auditory cues improved manipulation performance and subjective reports of usability for an assembly task. Twenty-four volunteers (12 males and 12 females) were required to assemble and then disassemble five interconnecting virtual parts with either auditory, force, or no feedback cues provided. Performance for the assembly task was measured using completion time and number of collisions between parts, while the users preferences across conditions were evaluated using subjective reports of usability. The results indicated that the addition of force feedback slowed completion time and led to more collisions between parts for males. In contrast, females exhibited no change in the mean completion time for the assembly task but did show an increase in collision counts. Despite these negative performance findings when adding force feedback, users did report perceived increases in realism, helpfulness and utility towards the assembly task when force feedback was provided. Unlike force feedback, the results showed that auditory feedback, indicating that parts had collided during the assembly task, had no negative performance effects on the objective measures while still increasing perceived realism and overall user satisfaction. When auditory cues and force feedback were presented together, performance times, number of collisions, and usability were not improved compared to conditions containing just auditory cues or force feedback alone. Based on these results, and given the task and display devices used in the present study, the less costly option of excluding auditory and force feedback cues would produce the best performance when measured by the number of collisions and completion time. However, if increased ratings of usability for an assembly task are desired while maintaining objective performance levels and reduced cost, then the inclusion of auditory feedback cues is best.     

计算听觉场景分析介绍

介绍了计算听觉场景分析的研究内容、理论依据、归类线索及意义,并以听觉的两大类型（数据驱动及图式驱动）为框架较详细地阐述了计算听觉场景分析系统的主要结构及研究进展,指出了信息双向互流将是未来CASA研究的主要模式。