The Effects of Deafness and Visual Language Experience on Visual Perception from Infancy to Adulthood

聋人必须比正常人更多地依赖视觉信息来理解他们周围发生的事情。因此，聋人的大脑通常会进行重组，以帮助他们更好地利用现有的视觉信息。这个研究项目解决的问题是对视觉信息的依赖是否以及如何改变视觉体验。该项目还调查了听力正常和失聪的人在婴儿期、儿童期和成年期的视觉处理差异。有证据表明，聋人的视觉方面会发生改变或增强，这为人类大脑的可塑性提供了证据，以弥补声音的缺失。然而，对于这些变化是如何在开发过程中出现的，我们知之甚少。该项目研究了在发育过程中改变早期感官体验的后果，测量了对运动、形式、面孔和物体的感知敏感性。聋人改变这些视觉方面的处理可能有两个原因。首先，听觉输入的缺乏迫使聋人更多地依赖于他们完整的视觉形态，其次，许多聋人使用视觉语言（美国手语，ASL），这可能会增强视觉处理的某些方面，传达重要的语言信息。为了区分耳聋和美国手语语言体验的影响，研究将比较手语和非手语聋人的视觉敏感性。此外，耳聋的影响可能发生在早期的关键时期，而不是由于一生中积累的感官体验改变。为了解决这种可能性，该项目还将包括研究一组“听力恢复”的儿童，他们在出生后的一段听力剥夺期后，在12-18个月左右接受了耳蜗植入。这些研究的结果将揭示感觉系统如何适应改变的输入，并阐明大脑可塑性的机制，这可能对聋哑人、盲人以及那些后来失去听力或视力的人有广泛的影响。

Deaf individuals must rely more than hearing individuals on visual information to understand what is happening in the world around them. As a result, the brains of deaf people typically reorganize to help them make better use of the available visual information. The questions addressed by this research project are whether and how greater reliance on visual information actually changes visual experiences. The project also investigates how differences between hearing and deaf people's visual processing develop across infancy, childhood, and adulthood.There is evidence that aspects of vision are altered or enhanced in deaf people, providing evidence for plasticity of the human brain to compensate for the absence of sound. Yet, very little is known about how these alterations emerge during development. This project investigates the consequences of altered early sensory experience during development, measuring perceptual sensitivity to motion, form, faces, and objects. Deaf people may have altered processing of these aspects of vision for two reasons. First, lack of auditory input compels deaf people to rely more on their intact visual modality, and, second, many deaf people use a visual language (American Sign Language, ASL), which may enhance certain aspects of visual processing that convey critical linguistic information. To tease apart effects of deafness versus ASL language experience, the studies will compare visual sensitivity in Deaf and Hearing individuals who are either Signers or Nonsigners. Also, effects of deafness could occur during an early critical period rather than due to accumulated altered sensory experiences across the lifespan. To address this possibility, the project will also involve studying a group of "Hearing Restored" children who received cochlear implants around 12-18 months, following a period of auditory deprivation starting at birth. Results from these studies will reveal how sensory systems adjust to altered input and elucidate mechanisms of brain plasticity, which may have widespread implications for deaf and blind individuals, as well as for those who lose their hearing or sight later in life.