The extraordinary triumph of the neuroscientists in California who have wired up a paralysed man’s brain so that his impulses to move can control a robot arm deserves a toast – and not just the drink that Erik Sorto can now raise unaided to his lips for the first time in 13 years. It also shows the importance of research on higher primates. Without detailed preliminary studies on monkeys, whose brains in important respects resemble our own, this kind of transformative treatment could never have been attempted.

Yet there is a determined pushback against all research on primates, which earlier this month drove one of Germany’s leading scientists out of the field. The prominent researcher Nikos Logothetis decided to abandon his work on macaques after a campaign against his work in Germany involving threats to him, his co-workers and their families. Logothetis’s experiments have established very clearly that the cloudy if colourful images shown by functional magnetic resonance imaging (fMRI) scans – which are the “brain scans” of popular science – actually correspond to the firing of individual neurons. This looks obvious, but it’s not in fact at all easy to prove; fMRI is necessarily coarse in its resolution of brain activity. There are something like 86bn neurons in the human brain, and in the interesting parts they are very closely packed together, so a precise determination of which does what requires a precision that fMRI just can’t deliver. The electrode patches used on Erik Sorto are only 4mm square.

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Partly owing to Logothetis’s work, we now know that the recognition of faces, which is important in social primates like ourselves and macaques, does sometimes involve the firing of single, specific neurons which have been trained to recognise particular faces, whether of people or monkeys. This is work that could only have been done using brain surgery to implant the electrodes which measure neuronal activity, and only on primates, whose social system is largely based on visual cues. Other social animals like dogs or rats can recognise one another as individuals, but seem to do so by smell rather than sight. But face processing is done in human brains in very similar ways to those in which it has evolved in macaques. So here is a specific and valuable advance in knowledge that could only have been attained by experimentation on animals that closely resemble us; experiments which are, as far as we can tell, almost painless.

Yet Logothetis has been driven from his primate lab. This is reminiscent of the prolonged campaign against Huntingdon Life Sciences in this country. In both cases the opponents of all animal experimentation gain their ends by frightening anyone less passionately intense. We must resist them. On 3 June the EU will review its humane rules on animal experiments. They should not be changed. This is not a fight between intellect and emotion, or reason and feeling, but between two modes of feeling and in the end compassion for humans, and that urge to understand which seems uniquely human should triumph over sentimentality and fear.