activator
aggravation
agitation
animation
animator
antecedents
arousal
arouser
arousing
bait
base
basis
boost
bribe
call
carrot
catalyst
causation
cause
cause and effect
determinant
determinative
electrification
element
encouragement
energizer
etiology
exacerbation
exasperation
excitation
excitement
exhilaration
factor
fillip
fomentation
galvanization
goad
ground
grounds
human dynamo
impetus
impulse
incentive
incitation
incitement
inducement
stimuli
activity
attraction
distraction
disturbance
exertion
impression
influence
input
irritation
manifestation
perception
response
restraint
stimulation
stress
symptom
variation