Tommy was a very easy baby. His mother remembers that he was happy to

lie in is crib for hours on end, watching his mobile. B age 2 Tommy was using

long, complicated sentences ad new the name of every mode of vehicle on

the road, as well as the names of most of the parts of their engines. At age 4

he took apart the family lawn mower and put it back together. However, his

preschool teacher was concerned about him. He took almost no interest in

the other children, choosing, when he spoke, to speak only to adults. When

he did talk, he invariably asked complex bur inappropriate questions on his

few topics of interest, such as mechanical objects. He dwelled incessantly on

a few events that were of great importance to him, such as the time the family

car doors would not open. Tommy seemed very bright in many ways and did

dwell on an IQ test that was part of his kindergarten screening. But in social

settings, he just did not know how to relate, and his language was used

primarily to talk about his own preoccupations rather than real interactions