Baldwin effect
From Wikipedia, the free encyclopedia
|
POSSIBLE COPYRIGHT INFRINGEMENT |
| If you have just labeled this page as a possible copyright infringement, please add the following to the bottom of Wikipedia:Copyright_problems/2007_April_8/Articles * {{subst:article-cv|Baldwin effect}} from [http://www2.create.human.nagoya-u.ac.jp/baldwin/introduction.html]. ~~~~ |
 The previous content of this page appears to infringe on the copyright of the text from the source(s) below and is now listed on Wikipedia:Copyright problems: Do not edit this page until an administrator has resolved this issue.
Unless the copyright status of the text on this page is clarified, it will be deleted one week after the time of its listing. |
|
|
|
The Baldwin effect, also known as Baldwinian evolution or ontogenic evolution, is an early evolutionary theory proposed by American psychologist James Mark Baldwin which proposes a mechanism for specific selection for general learning ability. Selected offspring would tend to have an increased capacity for learning new skills rather than being confined to genetically coded, relatively fixed abilities. In effect, it places emphasis on the fact that the sustained behavior of a species or group can shape the evolution of that species.
In 1896, Baldwin proposed that individual learning can explain evolutionary phenomena that appear to support Lamarckian inheritance. He saw the Baldwin Effect, which he called organic selection, as a reconciliation between Lamarckian evolution and Darwinian evolution. It proposed that the ability of individuals to learn can guide the evolutionary process, facilitating evolution by smoothing the fitness landscape. Baldwin further proposed that abilities that initially require learning are eventually replaced by the evolution of genetically determined systems that do not require learning. Thus learned behaviors may become instinctive behaviours in subsequent generations, without invoking the discredited Lamarckian inheritance. Unlike Lamarckian evolution, it does not involve direct transfer of learned abilities from generation to generation.
As an example, suppose a species is threatened by a new predator and there is a behavior that makes it more difficult for the predator to kill individuals of the species. Individuals who learn the behavior more quickly will obviously be at an advantage. As time goes on the ability to learn the behavior will improve (by genetic selection), and at some point it will seem to be an instinct.
The appearance of lactose tolerance in human populations with a long tradition of raising domesticated animals for milk production has been suggested as another example. This argument holds that a feedback loop operates whereby a dairy culture increases the selective advantage from this genetic trait, while the average population genotype increases the collective rewards of a dairy culture.
The Baldwin effect theory has always been controversial, with scholars being split in "Baldwin boosters" and "Baldwin sceptics". There have been a number of arguments against the effect. For example, it has been argued that the change from learning to instinct might not constitute an improvement, because only very stable environments where change is extremely slow would favour innate traits as opposed to the plasticity of learning (especially social learning, which doesn't have such high costs as individual learning by trial-and-error). The very mechanism of the transition has also been questioned, as genetic variations which "tend to decouple [...] behaviour from environmental signals" might be "distant from those genotypes that mediate plastic, learned response". [1]
[edit] See also
[edit] References
- Baldwin, Mark J. A New Factor in Evolution. The American Naturalist, Vol. 30, No. 354 (Jun., 1896), 441-451.
- Osborn, Henry F. Ontogenic and Phylogenic Variation. Science, New Series, Vol. 4, No. 100 (Nov. 27, 1896), 786-789.
- Baldwin, Mark J. Organic Selection. Science, New Series, Vol. 5, No. 121 (Apr. 23, 1897), 634-636.
- Hall, Brian K. Organic Selection: Proximate Environmental Effects on the Evolution of Morphology and Behaviour. Biology and Philosophy 16: 215-237, 2001.
- Bateson, Patrick. The Active Role of Behaviour in Evolution. Biology and Philosophy 19: 283-298, 2004.
- Sterelny, Kim. 2004. The Baldwin Effect and Its Significance: A Review of Bruce Weber and David Depew (eds) Evolution and Learning: The Baldwin Effect Reconsidered; MIT Press, Cambridge, Mass 2003, pp x, 341. To appear in: Evolution and Development. [2]
