298 PROMOTING POTENTIALthese correlations, however. One question is whether cognitive functions
are being directly aff ected or the treatments merely result in changes to
general health and vitality. Th e latter, for example, have signifi cant ef-
fects on any demanding task, not just test per for mances.
And there are some inconsistencies. As regards the Dutch Famine
Study, for example, some follow- ups in adulthood have found “ little or no
suggestion of any impact of exposure to famine on cognitive functioning.”^13
In a study reported in 2014, a group of mothers received a protein- energy
supplement, in the form of biscuits, from week 20 of gestation to birth. A
control group received the same biscuits only for six months, starting
from delivery. As Stein says in his review, “In this study, no diff erences
were seen between the groups in several mea sures of cognitive develop-
ment mea sured at the mean age of 19 y[ears].”^14
Th ese studies suggest that cause and eff ect are more complicated than
expected. Again, it may be that timing is crucial to consequences. For
example, the review by Huff man and colleagues suggests there is no evi-
dence for improvements in growth following fatty acid supplementation
in children greater than two years of age. Nevertheless, the fi ndings have
suggested a fairly simple “growth” model from inputs to outputs and clear
implications for intervention. But these concern fairly well- defi ned, iden-
tifi able, material factors.
EFFECTS OF SOCIO- PSYCHOLOGICAL FACTORSMost research into environmental eff ects on mental development has
prioritized socio- psychological factors, which tend to be less well defi ned
than those just described. Consequently, some studies have been very
broad and others more specifi c. And they involve less well- defi ned causal
models of development and individual diff erences.
Demonstrating that “global” deprivation in infancy can have long-
term eff ects has been a longstanding research program. One of the best-
known contributions has been the English- Romanian Adoption Study. It
carried out regular assessments on a group of Romanian orphans who
had experienced a profoundly deprived institutional environment. As
well as being malnourished, they spent most of the time alone in cribs,
lacking physical, social, visual, and auditory stimulation. Th e study is of
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