(pre DIS) I undertook an analysis of agricultural societies while studying for my MSc at the University of Melbourne, and published an ethological analysis of early farming which was re-published in 2000.
Evolutionary psychologists propose that human behaviour is produced by domain-specific ‘mental organs’ which evolved to produce adaptive responses in the human environment of evolutionary adaptedness (EEA). For humans the EEA is the Pleistocene era, which ends with the adoption of agriculture and appearance of complex societies. In a modern environment containing novel stimuli, behavioural responses can be non-adaptive. Behaviour is controlled at a proximate level by neural reward circuits which define the range of behaviour an animal can perform, via psychological reward when the animal achieves reproductive advantage and dysphoria in situations where reproductive success is unlikely. A feature of our modern environment is the wide availability of technologies for achieving psychological reward without reproductive success (see Nesse 1994). My suggestion was that these cultural artifacts constitute a significant subset of the novel stimuli identified by evolutionary psychology as
causing non-adaptive behaviour. By artificially inducing reward, these artifacts reduce the subjective importance of competing for and achieving reproductive success. Attenuation of individual competition supports new social structures which depend on segments of the population foregoing resources for the benefit of non-kin.
This model can be applied whenever an artificially-rewarding artifact is identified. My 1993 paper applies it to opioid peptides which are known to exist in some of the staples of early agriculture. Because complex social structures usually followed the adoption of agriculture in human populations, I argued that exorphins helped these social structures to appear.
Hillman et al (2003) suggested that exorphins could motivate the maintenance of agriculture, though not its initial adoption.
Hillman G, Hedges R, Moore A, Colledge, S., and Pettitt, P. (2001)
New evidence of Lateglacial cereal cultivation at Abu Hureyra on the Euphrates
Holocene 11 (4): 383-393
The ethological view of a mismatch between neurophysiological mechanisms of reward and the modern availability of pharmacological reward was first articulated by Nesse. Recently Sullivan and Hagen suggested that some self-administration may be adaptive.
Nesse, R. M. (1994)
An evolutionary perspective on substance abuse.
Ethology and Sociobiology, 15: 339#8211;348
Sullivan, R.J. and Hagen, E.H. (2002)
Psychotropic substance-seeking: evolutionary pathology or adaptation?
Addiction, 97: 389-400
Pharmacological research into exorphins has been primarily carried out by Takahashi and Fukudome’s group in Japan, and Teschemacher’s group in Germany. Recent publications include:
Yoshikawa M. Takahashi M. Yang S. (2003)
Delta opioid peptides derived from plant proteins
Current Pharmaceutical Design. 9(16):1325-30
Teschemacher, H. (2003)
Opioid receptor ligands derived from food proteins
Current Pharmaceutical Design, 9: 1331-1344
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