Failure to Thrive

     Scientific language is so wonderfully circumlocutory sometimes.  Here, for example, is a masterpiece of euphemism:

     “It is difficult or impossible to study scientifically the impacts of culturally produced social isolation at the human level.  The variables are multitudinous and recalcitrant to experimental manipulation and control.” [emphasis mine]

     What that means is that, for ethical and logistical reasons, we cannot take two equal groups of human children, raise one in normal social and familial settings, raise the other alone in boxes with no human contact, and see what happens.

     This quote comes from the introduction of Harry Harlow’s famous 1965 paper, ‘Total Social Isolation in Monkeys’.  I have recently become obsessed with social isolation, an obsession triggered by an experiment on natural language carried out by Frederick II, Holy Roman Emperor (see previous post).  Frederick wanted to know what language, if any, human children spoke innately, so he took some infants and raised them alone in a room, with minimal care and no affection.  They all died.

     This is the most dire manifestation of a phenomenon, itself a marvel of medical delicacy, called ‘failure to thrive’ (in fact, ‘failure to thrive’ has been deemed too blunt, and is being phased out by ‘faltering growth’, which certainly does sound more hopeful).  ‘Failure to thrive’ refers either to insufficient growth, or inappropriate loss of weight, and among its many exogenous causes is extreme emotional neglect.

     The recognition that affection is a medical necessity for young primates came late to humanity, it seems, and Harry Harlow was one of the first people to scientifically document the fact.  His experiments remain extremely controversial; one of Harlow’s doctoral students, Gene Sackett, apparently attributed the genesis of the animal rights movement to reaction against them.

     For the 1965 paper, which does not contain his most extreme experiments, Harlow placed newborn macaques, only several hours old, in isolation chambers for periods of three, six, and twelve months, and then observed their reintroduction to social groups.  During the period of their isolation, the baby monkeys were fed adequately but deprived of any human or monkey contact.  Despite Frederick’s grisly precedent, none of the monkeys died during isolation; however, when released, two of the three month isolates refused to eat, and one starved itself to death.  Harlow calls this “emotional anorexia”, and describes the effect of coming out of isolation as “emotional shock”.

     Harlow found that the social impairments of the three month isolation could be reversed, while some of those of the six month isolation could not.  Twelve months of isolation “almost obliterated the animals socially”; they were unable even to learn how to play.  Harlow had to stop testing them because the normal, control animals became so aggressive towards the “helpless isolate animals” that experimenters were afraid that they would kill them.

     The paper summarizes:

     “The findings of the various total-isolation and semi-isolation studies of the monkeys suggest that sufficiently severe and enduring early isolation reduces these animals to a social-emotional level in which the primary social responsiveness is fear.”

Harlow 1965 - Figure 4

Figure 4 from the 1965 paper, “autistic self-clutching”, one of the symptoms of “emotional shock”.

For a very good scientific biography of Harlow and explanation of his social and scientific context, read Deborah Blum’s Love at Goon Park: Harry Harlow and the Science of Affection.

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