The role of attention is especially important in perception

The role of attention is especially important in perception as it  determines which information is inputted and encoded (which also affects  memory and learning). Most variations in processing are due to  individual differences in cognition and/or environmental conditions that  may impact attention. However, perceptual “deficits” are often caused  by neurological abnormalities that impact everyday functioning. How  might any of the above factors affect one or more aspects of perception?  Provide examples.