G. Willemsen et al., Secretory immunoglobulin A and cardiovascular activity during mental arithmetic: effects of task difficulty and task order, BIOL PSYCH, 52(2), 2000, pp. 127-141
Secretory immunoglobulin A (sIgA) in saliva and cardiovascular activity wer
e measured at rest and during mental arithmetic. Task difficulty was manipu
lated by presenting easy, hard, and impossible versions of the mental arith
metic task in counterbalanced order, while task novelty was operationalised
as order of presentation (i.e. first, second, third). Mental arithmetic el
icited significant increases in sIgA concentration and sIgA secretion rate,
as well as significant cardiovascular effects. Performance decreased and r
ated difficulty increased with increasing task difficulty. However, sIgA an
d cardiovascular activity, with the exception of diastolic blood pressure,
were insensitive to variations in task difficulty. In contrast, sIgA concen
tration and a broad range of cardiovascular variables were influenced by ta
sk novelty, with more pronounced activity characterising the task version p
resented first, irrespective of its level of difficulty. Task novelty would
seem to be a more important determinant of sIgA and cardiovascular activit
y than task difficulty. (C) 2000 Elsevier Science B.V. All rights reserved.