Studies examining the association between laboratory
measures of stress-related cardiovascular (CV) reactivity
and responses to psychological challenges in the natural
environment have yielded mixed results. Frequently, single
laboratory tasks have been used to predict responses to
natural stressors on a single occasion of measurement.
Because aggregation broadens the range of stimuli sampled
and reduces measurement error, laboratory-to-life generalizability
should be more easily detected when multiple predictor
and criterion observations are used. Sixty students in
a public speaking course were administered multitask assessments
of CV reactivity during two laboratory sessions and during
two in-class public speech assignments. CV responses to
the classroom speeches were greater among those who showed
larger responses in the laboratory, and these associations
became stronger as measures were aggregated across multiple
samples of behavior. These results support the generalizability
of CV reactivity as a measure of individual difference,
and they help to shed light on previous inconsistent findings
in this area.