Saccades compress space, time and number

It has been suggested that space, time and number are represented on a common subjective scale. Saccadic eye movements provide a fascinating test. Saccades compress the perceived magnitude of spatial separations and temporal intervals to approximately half of their true value. The question arises as to whether saccades also compress number. They do, and compression follows a very similar time course for all three attributes: it is maximal at saccadic onset and decreases to veridicality within a window of approximately 50ms. These results reinforce the suggestion of a common perceptual metric, which is probably mediated by the intraparietal cortex; they further suggest that before each saccade the common metric for all three is reset, possibly to pave the way for a fresh analysis of the post-saccadic situation.     

Stimulus generalization as a function of the delay between training and testing procedures: a reevaluation

Three groups of 12 pigeons each were trained to discriminate between lights of 550 mμ (S^D), correlated with 1-min variable-interval reinforcement and 570 mμ (S^Δ), correlated with extinction. Group A was tested for wavelength generalization in extinction 1 min after meeting the discrimination criterion; Group B was tested 24 hr later; Group C was tested 24 hr later after a 3-min (reinforced) warm-up with the S^D. The post-discrimination gradient of Group B was significantly flatter and showed significantly greater area shift than that of Groups A and C. The gradient of Group C was similar to that of Group A, indicating that the warm-up eliminated the effect of the delay period.     

Ignorance,Information and Autonomy

People have a powerful interest in geneticprivacy and its associated claim to ignorance,and some equally powerful desires to beshielded from disturbing information are oftenvoiced. We argue, however, that there is nosuch thing as a right to remain in ignorance,where a right is understood as an entitlementthat trumps competing claims. This doesnot of course mean that information must alwaysbe forced upon unwilling recipients, only thatthere is no prima facie entitlement to beprotected from true or honest information aboutoneself. Any claims to be shielded frominformation about the self must compete onequal terms with claims based in the rights andinterests of others. In balancing the weightand importance of rival considerations aboutgiving or withholding information, if rightsclaims have any place, rights are more likelyto be defensible on the side of honestcommunication of information rather than indefence of ignorance. The right to free speechand the right to decline to acceptresponsibility to take decisions for othersimposed by those others seem to us moreplausible candidates for fully fledged rightsin this field than any purported right toignorance. Finally, and most importantly, ifthe right to autonomy is invoked, a properunderstanding of the distinction between claimsto liberty and claims to autonomy show that theprinciple of autonomy, as it is understood incontemporary social ethics and English law,supports the giving rather than the withholdingof information in most circumstances.     

The knowing visual self

Like all information-processing systems, biological visual systems are limited by internal and external noise; but this noise never actually impinges on our conscious perception. An article recently published in the Journal of Vision suggests that, at least for orientation judgments, the visual system has access to its own noisiness and sets thresholds accordingly. This could well be a general principle in perception, with important and wide ranging consequences.     

The contribution of visual and vestibular information to spatial orientation by 6- to 14-month-old infants and adults

Although there is much research on infants' ability to orient in space, little is known regarding the information they use to do so. This research uses a rotating room to evaluate the relative contribution of visual and vestibular information to location of a target following bodily rotation. Adults responded precisely on the basis of visual flow information. Seven-month-olds responded mostly on the basis of visual flow, whereas 9-month-olds responded mostly on the basis of vestibular information, and 12-month-olds responded mostly on the basis of visual information. Unlike adults, infants of all ages showed partial influence by both modalities. Additionally, 7-month-olds were capable of using vestibular information when there was no visual information for movement or stability, and 9-month-olds still relied on vestibular information when visual information was enhanced. These results are discussed in the context of neuroscientific evidence regarding visual-vestibular interaction, and in relation to possible changes in reliance on visual and vestibular information following acquisition of locomotion.     

Provision of Genetics Services on Guam

Guam’s geographic isolation and lack of community resources have resulted in unique healthcare needs. In 2006, the Western States Genetic Services Collaborative (WSGSC) conducted a genetics needs assessment and found that professional development is limited, families lack access to genetic services, and improved coverage of genetic testing is needed. With funding from the WSGSC, a Guam genetics outreach clinic was established and staffed by genetic counselors and a medical geneticist from Hawaii. Four clinics have been held to date. Although several challenges have been encountered, including minimal coverage of genetic testing by Guam insurance companies, limited referrals for families with private insurance, and inappropriate referral indications, the outreach clinic has been successful at increasing access to genetic services and improving professional development. With more collaborative work by staff from Guam, Hawaii, and the WSGSC, provision and reimbursement of genetic services and testing will continue to improve.     

It looks easy! Heuristics for combinatorial optimization problems

Human performance on instances of computationally intractable optimization problems, such as the travelling salesperson problem (TSP), can be excellent. We have proposed a boundary-following heuristic to account for this finding. We report three experiments with TSPs where the capacity to employ this heuristic was varied. In Experiment 1, participants free to use the heuristic produced solutions significantly closer to optimal than did those prevented from doing so. Experiments 2 and 3 together replicated this finding in larger problems and demonstrated that a potential confound had no effect. In all three experiments, performance was closely matched by a boundary-following model. The results implicate global rather than purely local processes. Humans may have access to simple, perceptually based, heuristics that are suited to some combinatorial optimization tasks.     

Musical training generalises across modalities and reveals efficient and adaptive mechanisms for reproducing temporal intervals

Expert musicians are able to time their actions accurately and consistently during a musical performance. We investigated how musical expertise influences the ability to reproduce auditory intervals and how this generalises across different techniques and sensory modalities. We first compared various reproduction strategies and interval length, to examine the effects in general and to optimise experimental conditions for testing the effect of music, and found that the effects were robust and consistent across different paradigms. Focussing on a ‘ready-set-go’ paradigm subjects reproduced time intervals drawn from distributions varying in total length (176, 352 or 704 ms) or in the number of discrete intervals within the total length (3, 5, 11 or 21 discrete intervals). Overall, Musicians performed more veridical than Non-Musicians, and all subjects reproduced auditory-defined intervals more accurately than visually-defined intervals. However, Non-Musicians, particularly with visual stimuli, consistently exhibited a substantial and systematic regression towards the mean interval. When subjects judged intervals from distributions of longer total length they tended to regress more towards the mean, while the ability to discriminate between discrete intervals within the distribution had little influence on subject error. These results are consistent with a Bayesian model that minimizes reproduction errors by incorporating a central tendency prior weighted by the subject's own temporal precision relative to the current distribution of intervals. Finally a strong correlation was observed between all durations of formal musical training and total reproduction errors in both modalities (accounting for 30% of the variance). Taken together these results demonstrate that formal musical training improves temporal reproduction, and that this improvement transfers from audition to vision. They further demonstrate the flexibility of sensorimotor mechanisms in adapting to different task conditions to minimise temporal estimation errors.