OK. This is MUCH more complicated than it looks. You're getting into
molecular and cellular processes here as well as the biochemistry and etc.
of learning. Temperament, i.e., the level of reactivity to stimuli, level
of energy, speed of movement is set at "baseline" by the genetic code.
The animal is conceived with a baseline temperament. This is part
of the skeleton structure upon which Personality is based. An animal
has certain traits encoded in the DNA at conception. Whether these
traits are expressed in behavior depends on many things, which I will enumerate
for you below.
During gestation there are many events which may impact on the expression
of 'behavioral' traits. Such as level of noxious stimuli perceivable
by the fetus, nutritional status of the mother/fetus unit, trauma of any
type to the fetus or mother, hydration, heat, cold, etc. These all impact
the development of every trait [behavioral or physical] that the animal
has.
Once the animal is born, a whole new set of circumstances comes into
play in the development of Personality. LEARNING has an enormous impact.
So does IMPRINTING/BONDING. So do all forms of environmental situations
and stimuli. This harkens back to the Nature/Nurture controversy so popular
in the 1960's and 1970's. Among those knowledgeable in the biochemistry,
molecular biology, organismic biology, and population biology of behavior
and learning, THERE IS NO SUCH CONTROVERSY ANYMORE. There is intensive
and extensive interaction at all levels of development among genetic endowment,
environmental impact, and learning. Let me give you some examples:
An animal may have a high energy, highly reactive, what we call 'irritable'
temperament [that is biologically irritable which means it responds actively
to stimuli] but has a very low level of trauma, low level of external stimuli,
and they will develop a mellow but "frisky" personality [to use a 'scientific'
term]. Similarly, an animal may have a low energy, low responsive, non
irritable temperament and be exposed to trauma, poor nutrition, and lack
of bonding and turn into The Beast From Hell.
These effects are not 'psychological', they are pure physiology and
biochemistry. The effects of learning can override almost anything!
A high energy animal can be reduced to a shaking trembling mass of twitches
by a highly traumatic environment that gives him/her no way to avoid the
trauma. Give them a way to avoid the trauma the same animal may become
aggressive and belligerent.
A low energy animal may become lethargic and depressed by chronic trauma
or if they can see a way to avoid, they can become aggressive or run away.
So... what [you've heard] lacks accuracy and uses thinking that has
been out of date for 20 yrs.
Norla M. Antinoro, PhD.