The ethics of research involving animals - Nuffield Council on ...

T h e e t h i c s o f r e s e a r c h i n v o l v i n g a n i m a l s
a living animal (usually a rodent). This is because those who undertake such <strong>research</strong> believe
that this procedure is the most scientifically valid, and <strong>of</strong>ten the only way <strong>of</strong> determining
hormone function in physiology and development. <strong>The</strong> welfare implications for the <strong>animals</strong>
involved will vary depending on the kind <strong>of</strong> hormone and the dose administered. In humans,
hormonal imbalances can cause unpleasant symptoms, including lethargy and headaches.
Box 5.3: Example <strong>of</strong> <strong>research</strong> – How do
monkeys view faces?
Guo K, Robertson RG, Mahmoodi S et al. (2003) How do
monkeys view faces? – a study <strong>of</strong> eye movements Exp
Brain Res 150: 363–74.*
Perception <strong>of</strong> faces plays a crucial role in social
communication. <strong>The</strong> aim <strong>of</strong> this <strong>research</strong> was to study
accurately how faces are viewed by primates. <strong>The</strong>
<strong>research</strong>ers investigated the organisation <strong>of</strong> eye
movements in two adult male rhesus macaque monkeys
in response to facial images. Previous studies had
suggested similarities between humans and monkeys in
the neural mechanisms responsible for the perception
<strong>of</strong> faces. Thus, it was concluded that the results <strong>of</strong> this
study could be compared to findings obtained from
humans by less invasive means.
<strong>The</strong> monkeys underwent an operation under
anaesthesia to implant a head-restraint device (see
paragraph 4.47). Coils were then surgically implanted
into the white, outer layer <strong>of</strong> the eyeball (the sclera) so
that eye movements could be recorded. During
experiments, the monkeys were seated in ‘primate
chairs’ (see also Box 5.5), which enable the head <strong>of</strong> the
monkey to be fixed. <strong>The</strong> monkeys’ eye positions were
recorded while images <strong>of</strong> monkey and human faces
were presented on a computer screen.
It was already known that when monkeys are shown
faces <strong>of</strong> other monkeys, their eyes fix on the eyes in the
image. This particular experiment investigated the
visual process that occurs when the faces were
unfamiliar to the monkeys, and when the images were
inverted or scrambled. Differences in perceptual
processing when either a monkey or a human face was
shown were also assessed. It was found that the
monkeys exhibited similar eye scan patterns while
viewing both familiar and unfamiliar monkey faces, or
while viewing monkey and human faces. <strong>The</strong>re was a
greater incidence <strong>of</strong> fixation <strong>of</strong> the eye region <strong>of</strong> all the
face images, and particularly re-fixation <strong>of</strong> the eyes <strong>of</strong>
unfamiliar faces during the first few seconds,
confirming that the eyes are important for initial
identification. However, it was found that the eyes in
the scrambled face images were much less <strong>of</strong> a focus
than those in the upright or inverted faces. <strong>The</strong>
<strong>research</strong>ers concluded that, while viewing faces, the eye
movements in non-human primates are controlled by
more than one level <strong>of</strong> perceptual processing; i.e. that
the targeting <strong>of</strong> the eye region may occur at a relatively
low level <strong>of</strong> visual processing (before identification <strong>of</strong>
the object) and that the probability that the eyes will
become the eventual target in the image is affected by
higher levels.
With regard to welfare implications, the implants could
have caused discomfort; the monkeys would also have
needed to be carefully trained to avoid psychological
distress caused by the restraint during the experiment.
No reinforcements in the form <strong>of</strong> ‘rewards’ or
‘punishments’ were given during this procedure.
* This is an example <strong>of</strong> animal <strong>research</strong> that has been carried
out in the UK and published in a peer-reviewed journal.
Details relate to this specific example and should not be taken
to represent a ‘typical’ animal experiment. It is important to
note that individually published experiments usually form one
part <strong>of</strong> a continuing area <strong>of</strong> <strong>research</strong>, and the significance <strong>of</strong>
the results may therefore be difficult to interpret.
Study <strong>of</strong> the immune system
5.7 Many studies on living <strong>animals</strong>, <strong>involving</strong> mainly mice and rats, have been conducted to
examine the vertebrate immune system, and most current knowledge is based on this
<strong>research</strong>. <strong>The</strong> immune systems <strong>of</strong> <strong>animals</strong> and humans protect them from infection. If the
adaptive immune system is challenged by a particular infectious agent that it has previously
overcome, it is able to do so on subsequent occasions much more quickly and effectively.
Research on the adaptive immune system usually involves an initial immunisation <strong>of</strong> <strong>animals</strong>
with foreign (from another animal) biological molecules or cells or microorganisms such as
bacteria. Immune responses are characterised by the production <strong>of</strong> immune cells and
antibodies, which specifically recognise and help eliminate the foreign molecules, cells or
microorganisms (all referred to as antigens). Experiments <strong>of</strong> this kind provided the first
evidence that the cells responsible for adaptive immune responses were a class <strong>of</strong> white
blood cells called lymphocytes. In these experiments, rats or mice were irradiated with X-rays
to kill most <strong>of</strong> their white blood cells, including lymphocytes, rendering them unable to
make adaptive immune responses. When different cell types were transferred into these
<strong>animals</strong>, only lymphocytes were found to reverse this deficiency. <strong>The</strong> welfare <strong>of</strong> the <strong>animals</strong>
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