Complex sentence: The Taylor Manifest Anxiety Scale, often shortened to TMAS, is a test of anxiety as a personality trait, it was created by Janet Taylor in 1953 to identify subjects who would be useful in the study of anxiety disorders.
Split into simpler sentences: The Taylor Manifest Anxiety Scale is a test of anxiety as a personality trait. It was developed by Janet Taylor in 1953 to identify subjects who would be useful in the study of anxiety disorders.