As we all know, our experiences in life can affect our behaviour. We are inclined to think of the effects of experience on our behaviour as a modification of the software (psychology) of our brains, and not of the brain structure. However, there is now good evidence that maltreatment during early childhood can have enduring physical effects on the developing brain, leading to seriously maladaptive behaviour.
Our current biotechnological abilities do not allow us to repair this physical damage and this may have implications for the design of effective therapies to treat victims of childhood abuse. This whole subject was described by Martin Teicher in an article in Scientific American (March 2002).
Childhood abuse typically occurs during a period when the developing brain is being physically altered by experience. The extreme stress inflicted by the abuse can leave a permanent mark on brain structure and function.The abuse triggers a sequence of chemical and neurological changes that cause irreversible changes in the neural development of the brain. The details of these many chemical and neurological changes can be consulted in the original article by Teicher.
The behavioural ill-effects triggered by childhood physical or sexual abuse are well documented and can manifest themselves at any age in internally and/or externally expressed forms. Internal expression includes depression, anxiety, suicidal thoughts and post-traumatic stress. External expression can appear as aggression, delinquency, hyperactivity or substance abuse.
Teicher describes borderline personality disorder (BPD), a condition strongly associated with abuse suffered in early childhood. A person with BPD pictures others in black and white terms, building them up to heroic proportions and shortly thereafter tearing them down again after suffering a perceived slight. People with BPD can have sudden outbursts of intense anger and periodic bouts of paranoia. They tend to feel empty, to form intense unstable relationships, to experience self-destructive impulses, and to seek relief through substance abuse.
Teicher explains things in an evolutionary context. Evolution has produced a human brain that is moulded by experience during development. Historically, this must have had an adaptive advantage, even when severely stressful experiences were encountered during early development - surely a commonplace occurrence over the greater part of our evolutionary history.
ON balance, behaviours produced as a result of experiencing stress during early development were adaptive in the harsh conditions that pertained during our early evolutionary history. Today these same behaviours are no longer useful, but are harmful - e.g. the tendency to react aggressively to challenge without hesitation. In our gentler modern society, social bulwarks ensure that almost everyone can survive to the age of sexual maturity, barring fatal accident or disease.
The incidence of childhood abuse and neglect is high. Teicher reports that over three million allegations of childhood abuse and neglect are received annually in America and subsequent investigation finds evidence to substantiate about one million of these. These figures must be viewed with even greater concern now that there is evidence that such abuse inflicts permanent physical damage on the developing brain.
The new findings also have implications for the development of appropriate treatments for victims of childhood abuse. Teichner seems to be pessimistic in this regard in view of the underlying physical damage. However, promising new therapies are being developed. Of course the best solution to this problem is prevention.
And what about the question of personal responsibility for one's actions? Is a person who suffered childhood abuse and, as a consequence became deeply disturbed and subjected another person to severe abuse, personally responsible for his/her actions?
In my view the answer is yes, but calculation of the extent of responsibility must take mitigating circumstances into account. Extreme, but fairly common, responses to the question I pose divide into polar opposites. On one side are those who only consider punishment as a response to someone convicted of serious abuse. On the other side are those who absolve the perpetrator of personal responsibility, ascribing all blame to social conditioning, and prescribing only rehabilitation for the individual.
I don't agree with either of these positions. It seems to me that, while we remain in touch with reality, we can recognise decent behaviour and we each have a responsibility to behave decently, no matter how difficult it may be for us to exercise that decency. Of course, when making judgments on someone who has abused others, one must summon up sympathy in proportion to the genuine difficulties that person laboured under. But, to deny personal responsibility is to live in a world where nobody incurs blame for wrongdoing or merits praise for doing good.
William Reville is associate professor of biochemistry and director of microscopy at UCC.