Perceptual compensation for reverberation in speech identification: effects of single-band, multiple-band and wideband noise contexts

Perceptual effects of room reverberation on a "sir" or "stir" test-word can be observed when the level of reverberation in the word is increased, while the reverberation in a surrounding 'context I utterance remains at a minimal level. The result is that listeners make more "sit" identifications. When the context's reverberation is also increased, to approach the level in the test word, extrinsic perceptual compensation is observed, so that the number of listeners' "sir" identifications reduces to a value similar to that found with minimal reverberation. Thus far, compensation effects have only been observed with speech or speech-like contexts in which the short-term spectrum changes as the speaker's articulators move. The results reported here show that some noise contexts with static short-term spectra can also give rise to compensation. From these experiments it would appear that compensation requires a context with a temporal envelope that fluctuates to some extent, so that parts of it resemble offsets. These findings are consistent with a rather general kind of perceptual compensation mechanism; one that is informed by the 'tails' that reverberation adds at offsets. Other results reported here show that narrow-band contexts do not bring about compensation, even when their temporal-envelopes are the same as those of the more effective wideband contexts. These results suggest that compensation is confined to the frequency range occupied by the context, and that in a wideband sound it might operate in a 'band by band' manner.

Brief cognitive behavioural therapy for extreme shape concern: an evaluation

Objectives. This study was designed to evaluate a new brief cognitive-behavioural intervention to reduce concerns about body shape. Design. Women with high levels of shape concern (N = 50) were randomly assigned to cognitive behaviour therapy or applied relaxation (AR). Baseline assessments were made and then women received their treatment immediately after this assessment, ('immediate' treatment) or 5 weeks after this assessment, during which time no treatment was given ('delayed' treatment, DT). Methods. Shape concern and related cognitions and emotions were assessed at baseline, post-treatment and at 4 and 12 week follow-up (FU). Results. Immediate treatment was superior to DT in reducing shape concerns, and this difference was maintained at 4 week FU. The cognitive behavioural intervention was more effective than AR in changing shape concern and this difference was largely maintained for 3 months. Conclusions. These initial findings support the further investigation of this brief intervention.

The spatial and temporal shape of oculomotor inhibition

Selecting a stimulus as the target for a goal-directed movement involves inhibiting other competing possible responses. Inhibition has generally proved hard to study behaviorally, because it results in no measurable output. The effect of distractors on the shape of oculomotor and manual trajectories provide evidence of such inhibition. Individual saccades may deviate initially either towards, or away from, a competing distractor - the direction and extent of this deviation depends upon saccade latency, target predictability and the target to distractor separation. The experiment reported here used these effects to show how inhibition of distractor locations develops over time. Distractors could be presented at various distances from unpredictable and predictable targets in two separate experiments. The deviation of saccade trajectories was compared between trials with and without distractors. Inhibition was measured by saccade trajectory deviation. Inhibition was found to increase as the distractor distance from target decreased but was found to increase with saccade latency at all distractor distances (albeit to different peaks). Surprisingly, no differences were found between unpredictable and predictable targets perhaps because our saccade latencies were generally long (similar to 260-280 ms.). We conclude that oculomotor inhibition of saccades to possible target objects involves the same mechanisms for all distractor distances and target types. (C) 2009 Elsevier Ltd. All rights reserved.

A longitudinal study of perceptual grouping by proximity, luminance and shape in infants at two, four and six months

Grouping by luminance and shape similarity has previously been demonstrated in neonates and at 4 months, respectively. By contrast, grouping by proximity has hitherto not been investigated in infancy. This is also the first study to chart the developmental emergence of perceptual grouping longitudinally. Sixty-one infants were presented with a matrix of local stimuli grouped horizontally or vertically by luminance, shape or proximity at 2, 4, and 6 months. Infants were exposed to each set of stimuli for three presentation durations. Grouping was demonstrated for luminance similarity at the earliest testing age, 2 months, by shape similarity at 4 months, but was not observed for grouping by proximity. Grouping by shape similarity showed a distinctive pattern of grouping ability across exposure durations, which reflected familiarity preferences followed by novelty preferences. This remained stable across age. No link was found between the emergence of perceptual grouping ability and the exposure duration required to elicit grouping. We conclude by stressing the importance of longitudinal studies of infant development in furthering our understanding of human cognition, rather than relying on assumptions from the adult endstate.

The roles of perirhinal cortex, postrhinal cortex, and the fornix in memory for objects, contexts, and events in the rat

Investigation of the anatomical substructure of the medial temporal lobe has revealed a number of highly interconnected areas, which has led some to propose that the region operates as a unitary memory system. However, here we outline the results of a number of studies from our laboratories, which investigate the contributions of the rat's perirhinal cortex and postrhinal cortex to memory, concentrating particularly on their respective roles in memory for objects. By contrasting patterns of impairment and spared abilities on a number of related tasks, we suggest that perirhinal cortex and postrhinal cortex make distinctive contributions to learning and memory: for example, that postrhinal cortex is important in learning about within-scene position and context. We also provide evidence that despite the strong connectivity between these cortical regions and the hippocampus, the hippocampus, as evidenced by lesions of the fornix, has a distinct function of its own-combining information about objects, positions, and contexts.

A novel shape feature for fast region-based pedestrian recognition

A new class of shape features for region classification and high-level recognition is introduced. The novel Randomised Region Ray (RRR) features can be used to train binary decision trees for object category classification using an abstract representation of the scene. In particular we address the problem of human detection using an over segmented input image. We therefore do not rely on pixel values for training, instead we design and train specialised classifiers on the sparse set of semantic regions which compose the image. Thanks to the abstract nature of the input, the trained classifier has the potential to be fast and applicable to extreme imagery conditions. We demonstrate and evaluate its performance in people detection using a pedestrian dataset.

Customer experience quality: an exploration in business and consumer contexts using repertory grid technique

This study proposes a conceptual model for customer experience quality and its impact on customer relationship outcomes. Customer experience is conceptualized as the customer’s subjective response to the holistic direct and indirect encounter with the firm, and customer experience quality as its perceived excellence or superiority. Using the repertory grid technique in 40 interviews in B2B and B2C contexts, the authors find that customer experience quality is judged with respect to its contribution to value-in-use, and hence propose that value-in-use mediates between experience quality and relationship outcomes. Experience quality includes evaluations not just of the firm’s products and services but also of peer-to-peer and complementary supplier encounters. In assessing experience quality in B2B contexts, customers place a greater emphasis on firm practices that focus on understanding and delivering value-in-use than is generally the case in B2C contexts. Implications for practitioners’ customer insight processes and future research directions are suggested.