pdf blood donation costly signalling
TRANSCRIPT
Its just a little blood Lyle, H. F., Smith, E. A., & Sullivan, R. J. (2009). Blood donations as costly signals of donor quality. Journal of Evolutionary Psychology, 7(4), 263-286.
Why do we give blood in the first place? • Blood donation is pure altruism, there is NO
direct benefit to the donor
• This may explain shortages in blood supply
• The Costly Signalling Theory suggests donors are honestly signalling cooperative intent and good genetic health !• AIM: to see if -
• donors are seen as generous (supported) and healthy (supported)
• the perceived costs reduce likelihood of donating (supported)
• and differ between donors & non donors (supported) !
• so we can encourage others
MEthod: • 346 college students
completed an online survey assessing (using likert scales): • Cost of donating (Anxiety, pain,
negative health consequences, inconvenience) • Perceived generosity of
donors vs blood demand • perceived health of
donors • Likelihood to make a
future donation • Compared donor and non
donor groups
Results: • a s i g n i f i c a n t n e g at i v e
relationship was found between likelihood of future donation and both potential negative health consequences and anxiety
• D o n o r s w e r e f o u n d t o b e considerably less concerned about anticipated pain and anxiety than non donors
• Blood donors were perceived by both groups to be healthy and disease free, but being physically fit was deemed unnecessary
Discussion: • A costly signal only
s e rv e s a p o s i t i v e f u n c t i o n i f t h e receiver understands its worth
• The results show that people understood the need for blood, and so consider donation a generous & altruistic act
• Reduced anxiety in donors may make them more attractive as an ally or potential mate as they appear to cope better under pressure
• f u t u r e r e s e a r c h should test w e t h e r generosity of d o n o r s generalises to other circumstances
Luke Costley White