Nature Vs. Nurture PSC 113 Jeff Schank Outline •  Emergence and Causa=on •  Nature vs. Nurture: What is Nature? What is Nurture? –  The Program/Blueprint Metaphors –  Developmental Programs –  Causal Loops and Levels of Organiza=on •  Reduc=onism and Holism Emergence and Causa=on •  With our modern no=on of Aristotelian causa=on, we can characterize biological and other complex systems in terms of the first three causes Flocks of Starlings Schools of Fish Herds of Mammals Nest Thermoregula=on in Social Insects FIG. 12 An Apis dorsata [giant honey bees] colony. Workers are spread out on the comb to reduce brood nest temperature (Photo by Ben Oldroyd). Julia C. Jones and Benjamin P. Oldroyd (2007 )Nest Thermoregula=on in Social Insects.ADVANCES IN INSECT PHYSIOLOGY VOL.33, pp. 153-­‐191) FIG. 10 Apis florea [wild bees] colony (Photo courtesy of Nadine Chapman).
Workers that form the protective curtain covering the comb move closer together
at low ambient temperatures, and further apart at high ambient temperatures.
Julia C. Jones and Benjamin P. Oldroyd (2007)Nest Thermoregulation in Social
Insects. ADVANCES IN INSECT PHYSIOLOGY VOL. 33, pp. 153-191)
Nest Thermoregula=on in Social Insects Nature vs. Nurture: What is Nature? What is Nurture? •  A program is “a series of coded instruc=ons which when fed into a computer will automa=cally direct its opera=on in carrying out a specific task”. (A blueprint is plan, scheme, or pafern for something, i.e., Aristotle's formal cause.) Developmental Programs •  Although development does not proceed in a way that is analogous to a computer program, perhaps if we just consider development as a kind of “black box” with the environment providing input •
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Closed programs require no specific input (experience) for development to proceed on its gene=cally predetermined course. Open programs, however, require input or experience in order for developmental program to proceed. Closed X Open Cri=cal and Sensi=ve Periods •  Cri7cal period: A span or period of =me during which specific environmental input is essen=al if an ability is to develop –  Cri7cal period hypothesis for Language: There is a cri=cal period for language acquisi=on that ends with the onset of puberty; if an individual has not received sufficient linguis=c input by then, the individual is incapable of acquiring language •  Sensi7ve period: A span or period of =me during which specific environmental input is important for the development of an ability, but at least some aspects of that ability can be learned or acquired without receiving the input during a sensi=ve period •  Ques7on: is the acquisi=on of language subject to a cri=cal period, sensi=ve period, or no period at all? Dis=nc=on between Cri=cal and Sensi=ve Periods Cri7cal X Sensi7ve X X ? Tes=ng the Cri=cal Period Hypothesis for Language •  The problem with the cri=cal period hypothesis is that it is not testable in the laboratory •  We cannot take children into a laboratory and raise them with no language input un=l they reach puberty •  However, there have been cases of people who, out of extreme neglect, mistreatment, or unfortunate circumstances, did not receive language input before puberty Genie •  Genie existed for 10 years in a closet =ed to a pofy chair •  She had no discernible linguis=c abili=es at the =me she was found (age 13) •  Video Problems •  What other developmental effects did isola=on have on Genie? •  Was the research adequately conducted? •  Did Genie really fail to acquire syntax and grammar? •  Has there been scien=fic misconduct in the case of Genie? Peter E. Jones •  Concludes that these claims are false or misleading –
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Genie was unable to acquire the morphology of English. Genie was unable to acquire the syntax of English. Genie’s uferances remained uninflected and telegraphic Genie’s uferances remained hierarchically flat. Genie’s linguis=c development leveled off during period 1 (1971-­‐1975). Causal Loops and Levels of Organiza=on Example of Causal Loop (I don’t know if it is accurate) Reduc=onism •  Defini7on: Reduc=onism is the view that explana=ons of things and/or their behavior should be in terms of things that are simpler, more obvious, and/or more easily understood than the things themselves •  Historical Background –  In the 17th and 18th centuries, the Bri=sh philosophers Locke, Berkeley, and Hume, were concerned with how we come to have knowledge of the world and how the mind works –  For all of the them, the mind was essen=ally a bundle of ideas –  Twen7eth Century Logical Empiricists: Rudolf Carnap was probably the leading figure of this movement –  The problem concerned the interpreta=on of the things scien=fic theories are about—How can we know a thing in itself? –  Answer: Define all scien=fic terms in terms of statements about observa=ons using set theory and logic—It turned out not to be possible Reduc=onism •  Historical Background con7nued… –  Behaviorism originated from the complete rejec=on of anthropomorphism, anecdotalism, and introspec7onism at the turn of the century as typified in the behaviorism of J. B. Watson and B. F. Skinner –  Behaviorists start from the proposi=on the behavior of organisms can be studied as natural events and they sought to discover laws of associa=on among behavior and s=muli resul=ng from learning –  Problems: Oversimplified the environment, ignored what happens inside the organism, and ignored social learning and context Reduc=onism: Nature vs. Nurture •  Especially in the 20th century to today, many researchers have assumed that the behavior of organisms can be explained by some propor=on of nature (genes) or nurture (environment, experience). •  What propor=on of IQ is determined by genes (nature) and what propor=on by experience (nurture)? •  This ques=on makes it sound as though we can always answer such •  ques=ons by giving some percentage such as 60% of IQ is determined by the genes and 40% is determined by experience •  Research in animal behavior has revealed the rela=onship between genes, •  Experience and development are far from this simple (e.g., consider the ring dove reproduc=ve cycle) •  Thus, the nature vs. nurture dis=nc=on is reduc=onis=c in that it ignores causal loops up and down levels of organiza=on