The Psychology of Impulses By Dr David Lewis-Hodgson
Impulsivity (or impulsiveness) can be generally defined as the act of saying or doing things on the spur of the moment. A personality trait characterised by behaving without giving sufficient consideration to the likely consequences.
As a concept, impulsivity covers a wide range of poorly conceived, prematurely expressed, unduly risky, or inappropriate behaviours that often have undesirable and undesired outcomes.
It is a trait many would sooner deny than defend.
We prefer to see ourselves as thoughtful, rational, beings. To believe that we take important decisions only after careful reflection and slow deliberation.
In fact we far more frequently act on an emotion-driven impulse rather than after logical and reasoned reflection.
Whether motivated by joy, anger, resentment or the desire for revenge we think, speak and act impulsively. We blurt out indiscretions, rush to judgements, reach snap decisions and leap to conclusions. We make spur of the moment choices, make seat-of-the-pants assumptions and leaps of faith.
It doesn’t matter that we know better.
It doesn’t matter that we’re aware of the remorse we will later feel for our impulses, words and deeds. When the results of some ill-judged words or reckless action return to haunt us the only explanation we can come up with is, often: “It seemed like a good idea at the time.”
Impulsive behaviours are the root cause of the majority of personal and social problems, including drug and alcohol addiction, ranging from obesity, excessive spending, dysfunctional relationships, underachievement at school and beyond, smoking, unplanned and unwanted pregnancies, emotional difficulties and an inability to fulfil one’s ambitions.
At some point, our self-control simply deserts us and we fall in love with the wrong person, impulsively buy products we don’t need, take reckless financial risks, agree to a second helping of that delicious but waist expanding chocolate cake, allow “a couple of drinks” to turn into a steady flow of alcohol until closing time, jeopardise our health through over indulgence or succumb to peer group pressure and take part in highly dangerous youthful pranks.
As a personality trait, impulsivity should be seen as part of normal behavior that enables us to function adaptively in a rapidly changing world.
Among the young acting impulsively is relatively common and, especially in males, persists through adolescence and into the early twenties as the frontal regions (the decision making areas) of their brains slowly develop. The orbitofrontal cortex and right inferior frontal gyrus have been shown to play a part in impulse control.*
Recent studies suggest that impulsivity involves a number of factors  with some researchers proposing a 3-factor model involving:
(1) Attention – “quickly becoming bored”
(2) Motor function – “action”
(3) Cognition (“failure to plan”).
- Positive urgency – acting rashly whilst displaying a positive mood.
- Negative urgency – acting rashly whilst in a negative mood.
- Absence of premeditation – an inability to anticipate the future consequences of actions.
- Lack of perseverance – an inability to follow through on a task.
- Sensation seeking – positive feelings towards risk.
While, as mentioned above, impulsivity has a genetic component and is likely to be inheritable, it may also occur as the result of various pathologies such as traumatic brain injury (TBI), hypoxic ischemic encephalopathy, intrauterine hypoxia, bacterial or viral infections or neurotoxicity as a result of chemical exposure.
 Corsini, R. J. (1999),
 Berlin, HA; Rolls, ET; Kischka, U (2004)
 Salmond, CH; Menon, DK; Chatfield, DA; Pickard, JD; Sahakian, BJ (2005)
 Evenden, J.L. (1999)
* See References – Bibliography .