- Smoking as a Costly Signal
Signalling is the idea that in a population of individuals, some will send out signals as a sign of their quality (e.g. fitness as a mate) and some will receive signals to appraise potential mates. Senders benefit from having their signals accepted whereas receivers benefit from accepting signals from fit individuals. Say there is a poor signal and a good signal (i.e. the latter has a better chance of being accepted). Senders will want to send the good signal if they can. Costly signalling implies that they have to pay a greater cost for sending the better signal. Importantly, lower quality individuals pay a greater cost than higher quality individuals. Therefore there will tend to be an efficient separation such that receivers can be fairly confident that by accepting a costly signal they will be accepting a higher quality mate.In the animal kingdom, the peacock’s tail is a great example of costly signalling. The larger the tail, the more difficult it is for the peacock to fly. It seems surprising then that peacocks would evolve to have these cumbersome tails: surely they aren’t adaptive? Amotz Zahavi proposed the Handicap Principle to explain this: a male peacock with a large tail is signalling to peahens that he is so fit that he can still evade predators even with the handicap of a large tail (apologies for the terminology).Yesterday I asked myself why the dramatic increase in the price of cigarettes (at least in my part of the world) seemed to coincide with a dramatic decrease in their ‘coolness’. I thought that if I looked at the phenomenon from a costly signalling perspective then surely an increase in the cost of the signal should allow higher quality senders to more effectively separate themselves from lower quality ones.
A quick Google search returned the paper linked above. This doesn’t match my intuition for where I’m from but Dewitte (writing from Belgium) claims that adolescent smoking has become more popular and that the reason for this is in fact, costly signalling. Adolescents who are healthier (at least before they start smoking!) can signal their fitness by adopting this habit, effectively saying “I’m so healthy that I can afford to smoke”. Note the similarity to the peacocks. Although everyone can choose to smoke, less healthy people (say someone with asthma) pays a higher cost by smoking such that receivers can reliably infer that anyone who smokes doesn’t have underlying health problems (such that they are more attractive).