Scene layout from ground contact,occlusion, and motion parallax

An important factor in determining perceived scene layout is optical contact between objects and the ground surface (“ground contact”). The relation between ground contact and occlusion was investigated in four experiments with stationary and motion parallax scenes containing a pole that occluded or was occluded by one or more cylinders. Some judgements were inconsistent with occlusion in stationary scenes, but judgements were consistent with occlusion in motion parallax scenes. When the range of object positions consistent with occlusion did not include the positions specified by ground contract or by motion parallax, the ground contact and motion parallax information still had a quantitative effect on the perceived position of the object within the range consistent with occlusion. These results demonstrate a cooperative interaction between ground contact, occlusion, and motion parallax in determining perceived layout in 3-D scenes.     

独生与非独生儿童认知发展的比较研究(广州市)

为了研究中国独生子女政策可能造成的独生和非独生儿童的认知能力的差别,分别在广州七所小学一年级和五年级中选择了146名和171名独生与非独生儿童。用11项认知能力测验对这些儿童进行测查。一年级独生儿童在言语记忆和一般常识项目上的成绩优于非独生儿童。研究认为,一年级独生儿童在与一般认知能力有关的项目上具有优势。而五年级的独生儿童在认知作业成绩上,没有表现出显著性的优势。另外,独生男童在一般常识方面优于独生女童。作者用独生儿童受到较大的父母关注和投资来解释一年级独生对非独生儿童在认知方面的优势。随着儿童的自然成熟和学业教育,两者之间的差距会逐渐缩小,从而使五年级独生儿童未能在认知方面表现出明显的优势。     

Dichotic listening and otoacoustic emissions: shared variance between cochlear function and dichotic listening performance in adults with normal hearing

The present study investigated a possible connection between speech processing and cochlear function. Twenty-two subjects with age range from 18 to 39, balanced for gender with normal hearing and without any known neurological condition, were tested with the dichotic listening (DL) test, in which listeners were asked to identify CV-syllables in a nonforced, and also attention-right, and attention-left condition. Transient evoked otoacoustic emissions (TEOAEs) were recorded for both ears, with and without the presentation of contralateral broadband noise. The main finding was a strong negative correlation between language laterality as measured with the dichotic listening task and of the TEOAE responses. The findings support a hypothesis of shared variance between central and peripheral auditory lateralities, and contribute to the attentional theory of auditory lateralization. The results have implications for the understanding of the cortico-fugal efferent control of cochlear activity.     

Stereokinetic phenomena revisited: The oscillating tilted bar, the swinging gate and the vertical contracting bar

We present here a revised version of our mathematical modelling of the stereokinetic phenomena known as the “oscillating tilted bar”, the “swinging gate” and the stereokinetic phenomenon elicited by a vertical, periodically contracting line segment simultaneously undergoing a lateral displacement from left to right and conversely in the frontal plane of an observer. The criticisms of Liu, Z. [(2004). On the minimal relative motion principle—The oscillating tilted bar. Journal of Mathematical Psychology, 48, 196-198] and Rokers and Liu [(2004). On the minimal relative motion principle—Lateral displacement of a contracting bar. Journal of Mathematical Psychology, 48, 292-295.] helped us in reformulating our models, eliminating discrepancies and ambiguities. Characteristic of the present modelling is the clear definition of a multi-stage mathematical procedure matching different requirements posed by the Visual System, as we know them from our experimental observations.     

Generalizing attentional control across dimensions and tasks: Evidence from transfer of proportion-congruent effects

Three experiments investigated transfer of list-wide proportion congruent (LWPC) effects from a set of congruent and incongruent items with different frequency (inducer task) to a set of congruent and incongruent items with equal frequency (diagnostic task). Experiments 1 and 2 mixed items from horizontal and vertical Simon tasks. Tasks always involved different stimuli that varied on the same dimension (colour) in Experiment 1 and on different dimensions (colour, shape) in Experiment 2. Experiment 3 mixed trials from a manual Simon task with trials from a vocal Stroop task, with colour being the relevant stimulus in both tasks. There were two major results. First, we observed transfer of LWPC effects in Experiments 1 and 3, when tasks shared the relevant dimension, but not in Experiment 2. Second, sequential modulations of congruency effects transferred in Experiment 1 only. Hence, the different transfer patterns suggest that LWPC effects and sequential modulations arise from different mechanisms. Moreover, the observation of transfer supports an account of LWPC effects in terms of list-wide cognitive control, while being at odds with accounts in terms of stimulus–response (contingency) learning and item-specific control.     

Endurance exercise selectively impairs prefrontal-dependent cognition

Two experiments are reported that examine the possibility that exercise selectively influences different types of cognition. To our knowledge, these experiments represent the first attempt to study higher-cognitive processes during exercise. Theoretical thinking was guided by the transient hypofrontality hypothesis. In both experiments, athletes who exercised at a sustained, moderate pace were compared to sedentary controls on two neuropsychological tests, one that is generally regarded as heavily dependent on prefrontal cognition and one that is relatively insensitive to prefrontal operation. Results showed that during exercise performance on tests demanding prefrontal-dependent cognition was impaired, while at the same time, cognitive processes requiring little prefrontal activity were unaffected.     

Effects of a violation of an expected increase or decrease in intensity on detection of change within an auditory pattern

An infrequent physical increase in the intensity of an auditory stimulus relative to an already loud frequently occurring “standard” is processed differently than an equally perceptible physical decrease in intensity. This may be because a physical increment results in increased activation in two different systems, a transient and a change detector system (signalling detection of an increase in transient energy and a change from the past, respectively). By contrast, a decrease in intensity results in increased activation in only the change detector system. The major question asked by the present study was whether a psychological (rather than a physical) increment would continue to be processed differently than a psychological decrement when both stimuli activated only the change detector system. Participants were presented with a sequence of 1000 Hz tones that followed a standard rule-based alternating high-low intensity pattern (LHLHLH). They were asked to watch a silent video and thus ignore the auditory stimuli. A rare “deviant” was created by repeating one of the stimuli (e.g., LHLHLLLH. The repetition of the high intensity stimulus thus acted as a relative, psychological increment compared to what the rule would have predicted (the low intensity); the repetition of the low intensity stimulus acted as a relative, psychological decrement compared to what the rule would have predicted (the high intensity). In different conditions, the intensity difference between the low and high intensity tones was either 3, 9 or 27 dB. A large MMN was elicited only when the separation between the low and high intensities was 27 dB. Importantly, this MMN peaked significantly earlier and its amplitude was significantly larger following presentation of the psychological increment. Thus, a deviant representing an increment in intensity relative to what would be predicted by the auditory past is processed differently than a deviant representing a decrement, even when activation of the transient detector system is controlled. The psychological increment did not however elicit a later positivity, the P3a, often thought to reflect the interruption of the central executive and a forced switching of attention.