Biology Reference
In-Depth Information
These 'food calls' have been observed in a wide range of birds and primates, and a
number of possible explanations have been given, which include attracting others to
increase safety from predation, attracting potential mates and claiming ownership of a
resource (Searcy & Nowicki, 2005).
Mark Elgar (1986a, 1986b) observed that house sparrows often gave 'chirrup' calls
when they found food and that when others joined them they then flew down to feed
together. Playback of these calls confirmed that they attracted others. Furthermore,
sparrows adjust their level of calling in response to the likely benefit of attracting
others - individuals chirruped less when food was harder to share (a single lump of
bread rather than crumbs) and when predation risk was lower (nearer to cover; see also
the section on feeding and danger in Chapter 4).
Chirruping
attracts other
house sparrows
Human language
The evolution of human language was a major evolutionary transition that represents
a crucial difference between humans and other animals (Maynard Smith & Szathmary,
1995). Humans have a vocabulary of thousands of words, which can be arranged into
sentences capable of carrying an indefinitely large number of meanings. This has led
to the possibility for rapid cultural evolution, with traits being passed from one
generation to the next through teaching or social learning, rather than through genes.
Most research into human language has come from the field of linguistics, which has
focused on more mechanistic and proximate issues. However, we can also examine
language from a behavioural ecology perspective, asking questions such as what
factors would have favoured the evolution of language, and what maintains the
honesty of language?
Considering what maintains the honesty of human language, it is possible to imagine
that both social costs of lying (punishment or reputation; a form of handicap analogous
to badges of status) and common interest could have played a role, possibly in different
situations. For example, one individual might tell another which restaurant they are
going to because they want to meet there; whereas another individual might give
information about whether they have spare food because their reputation would suffer
if it was later found out that they had lied. Recent research has started to open up
possibilities for examining such issues, by examining the evolution of language in
controlled laboratory settings. Bruno Galantucci (2005) tested whether novel
communication systems could rapidly evolve in a laboratory setting. People were put
into pairs and made to play a game on the computer where the financially rewarded aim
was to get two 'agents' into the same room. The players were not allowed to interact
directly and instead could only communicate by drawing on a small digitizing pad,
which then sent the drawing to the other players. Galantucci found that whilst the
common interest of the financial reward led to most pairs solving the game by developing
a communication system, some did not, even after 160 minutes. In the pairs where a
communication system did arise, it took different forms. In some cases communication
was icon based, with individuals using different symbols to label the rooms, whereas in
others communication was map based, with individuals using the position or orientation
Honesty in human
language could be
maintained by the
social cost of lying
and/or common
interest
