It wasn't until the early 1980s, though, that convincing evidence for classical conditioning of the gill and siphon withdrawal reflexes could be obtained.

This is not the time for minor last-minute arrangements, sudden nationalistic reactions, or withdrawal reflexes that are in danger of making this Treaty lose all its coherence, by introducing lots of accommodating opt-outs.

Electroencephalography suggests the capacity for functional pain perception in premature infants probably does not exist before 29 or 30 weeks; this study asserted that withdrawal reflexes and changes in heart rates and hormone levels in response to invasive procedures are reflexes that do not indicate fetal pain.