Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Individual audio-only results for six contrasts as a function of age and contrast. Data points show the number of correct responses in eight trials. Scores of seven or eight are significantly better than chance at the .035 level and are indicated by open symbols. Overlapping data points have been shifted slightly to ensure visibility.
