Age-related changes may have been influenced by differences in
the interpretation of the instructions, but the overall response
pattern of older adults makes this unlikely. If older adults simply
misunderstood the instructions, thinking that they were required to
indicate when someone was displaying a happy facial expression,
they would not have shown sensitivity to the differences between
enjoyment and nonenjoyment smiles (i.e., they would likely have
said that every smiling individual was happy). Another possibility
is that older adults misinterpreted the label not happy as meaning
unhappy. However, if this were the case, then it would also seem
logical that older adults would have categorized those displaying
neutral expressions as happy because they also did not look unhappy.
In fact, older adults rarely categorized individuals with
neutral expressions as happy. This finding also suggests that the
bias found in this study was not due to older adults immediately
responding that an individual was happy without fully examining
the images. It therefore seems plausible that these results may
reflect an age-related positivity bias toward thinking that those
who are smiling are feeling happy even when their smiles do not
involve facial information that specifies underlying feelings of
happiness. This suggestion supports the SST, which proposes that
older adults tend to enhance positive emotional experience, resulting
in a bias toward positive interpretation of information
(Carstensen et al., 2003). In summary, the present study revealed
age-related similarities in the ability to discriminate between enjoyment
and nonenjoyment smiles but also a difference in that
older adults had a greater bias toward thinking that any smiling
individual was feeling happy