162
THE ESSEX NATURALIST
A Survey of Fallacies in Chelmsford
BY P. M. HAMMOND AND R. K. H. JONES
(King Edward VI School, Chelmsford)
The members of the Natural History Society of this school decided
to investigate the frequency of belief in certain well-known
biological fallacies amongst the adult population of the area.
Teams of two carried out a canvass in the district during which 271
people were asked twelve main and eight subsidiary questions designed
to test their belief in the following fallacies: —
That bats are blind.
That bats habitually get in people's hair.
That ostriches can eat almost anything without harm.
That ostriches bury their heads in sand.
That dragonflies sting.
That butterflies live only for a day.
That thunder turns milk sour.
That camels store water in their humps.
That edible mushrooms can be identified by their peeling or by not
blackening a silver spoon.
The questions were put in such a way that the answers were not
suggested to the "victims".
The results obtained were as follows : —
57 per cent of the sample said that bats were blind.
22 per cent said bats get into people's hair.
44 per cent thought ostriches could eat almost anything.
57 per cent thought ostriches buried their heads in sand.
32 per cent thought dragonflies stung and one-fifth of these claimed
to know people who had been stung by them.
33 per cent gave one or two days as the normal life span of a butter-
fly.
Only 19 per cent thought thunder turned milk sour.
54 per cent said camels stored water in their humps.
49 per cent held the very dangerous belief that it is safe to eat fungi
if they peel easily or fail to turn a silver spoon black.
The 95 per cent confidence limits for this sample, work out at ± 5
per cent, where 20 per cent subscribe to the fallacy; and at ± 6 per cent
where 60 per cent subscribe. In other words where 57 per cent of our
sample believe that bats are blind we can reasonably expect that between
51 per cent and 63 per cent of the whole population of Chelmsford will
hold the same belief.
It seems to us remarkable that in these days of education for all so
many such fallacies could have so great a currency, and even more
remarkable that some of them should ever have risen. Apart from the