humans retain many biological and psychological characteristics from their
animal ancestors that they share in common with other animals with the
same ancestors
impractical or unethical to do to humans
animals can be bred to see what effects show up in their descendants; they
can also be kept in a controlled environment and observed for long periods
Even if we accept evolutionary psychology, humans have evolved to be very
different from most other animal
Even if animals are genetically similar to humans, they only share a genotype
with us; they do not share a phenotype, which is a wider description of
biology and environment
Animals (Scientific Procedures) Act, 1986. Research needs a licence from
the Home Office; the premises must be licensed for animal research as must
every individual involved in the research. Laboratory animals must be
procured from “high quality suppliers” who comply with Home Office
standards.
Based on that, British Psychological Society (BPS) has published Guidelines
for Psychologists Working with Animals (2012).