70 Chapter 5The sensitive period
This is a time in an animal’s life when external experience can have the greatest influ-
ence on later behaviour. In cats, this period starts at around 2 weeks of age when the
kitten not only becomes sufficiently aware of its surroundings but it is also a time when
neural development and increased plasticity enhances the ability to learn (Knudsen,
2004). This increased sensitivity to learning starts to decline at around 7 weeks of age,
which may also be related to the emergence of adult-type escape and fear responses
at around 6–8 weeks of age (Kolb and Nonneman, 1975).
The sensitive period is not the only time when learning takes place, but the expe-
riences that a kitten is exposed to during this time can have the greatest influence in
shaping its behaviour for the rest of its life. The two learning processes that are of
most importance during this time are socialization and habituation:
● Socialization is the process whereby a young animal develops social attachments
and learns to recognize and to develop appropriate social behaviour with mem-
bers of its own species and with members of other species that it lives with.
● Habituation is the process whereby an animal learns to ignore non-threatening
events and stimuli.
Cats that have not experienced sufficient or appropriate socialization with people or
habituation to household noises, etc. during the sensitive period are likely to be unsuit-
able as domestic pets.
Socialization to cats, other species and people
A kitten’s early experience can affect how it interacts with other cats as an adult. Cats
that have had limited socialization with conspecifics are more likely to be fearful and
potentially aggressive towards other cats and demonstrate signs of distress if confined
with other cats later in life. Cats with a history of positive experience with other cats
during the sensitive period generally appear less stressed and more tolerant around
other cats as adults (Kessler and Turner, 1999).
Because the sensitive period starts to decline before pet kittens go to their new
homes, the only other cats that many kittens are exposed to are its mother and
littermates. Studies have shown that close-bonded relationships are far more likely to
exist between littermates that remain together than between non-related cats that live
in the same household (Bradshaw and Hall, 1999). It is unclear, however, if this is
simply because of the development of attachments during the sensitive period, regard-
less of relatedness, or if being related increases the likelihood of continued
attachment.
Experimenters have successfully raised and socialized kittens with other species,
even with animals that would normally be regarded as either prey or predator. In
studies where kittens were raised with rats, they grew up into cats that did not regard
similar rats as prey, although they would still attack rats of other strains (Kuo, 1930).
In another experiment, where kittens were raised with puppies, at 12 weeks of age
the kittens showed no fear and would happily play with other puppies, whereas kit-
tens of the same age with no experience of puppies showed fear, avoidance and defen-
sive behaviour (Fox, 1969).