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

聋人必须比听力正常的人更多地依靠视觉信息来理解他们周围世界正在发生的事情。因此，聋人的大脑通常会进行重组，以帮助他们更好地利用可用的视觉信息。这项研究项目解决的问题是，更多地依赖视觉信息是否以及如何真正改变视觉体验。该项目还调查了聋人在婴儿期、儿童期和成年期的听力和视觉处理能力的差异。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，人们对这些变化是如何在发展过程中出现的知之甚少。这个项目调查发育过程中早期感觉体验改变的后果，测量对运动、形状、面部和物体的感知敏感度。聋人可能因为两个原因改变了视觉的这些方面的处理。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通道，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，以传达关键的语言信息。为了区分耳聋和ASL语言体验的影响，这些研究将比较聋人和听力正常的人的视觉敏感度，这些人要么是手语者，要么是非手语者。此外，耳聋的影响可能发生在早期的危急时期，而不是由于一生中积累的感官经历的改变。为了解决这一可能性，该项目还将研究一组在出生时开始一段时间的听觉剥夺后，在12-18个月左右接受人工耳蜗植入的“听力恢复”儿童。这些研究的结果将揭示感觉系统如何调整以适应改变的输入，并阐明大脑可塑性的机制，这可能对聋人和盲人以及那些在晚年失去听力或视力的人产生广泛的影响。

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.