The 1992 Darwin Lecture was delivered in the lecture theatre of the Linnean Society on 10 November 1992 by Professor Robert Hinde, Master of St John's College, Cambridge.
Professor Hinde said that by aggression he meant behaviour directed towards doing harm to others - not assertiveness which is a different but possibly related aspect of behaviour.
The levels of social complexity at which aggression can be studied are:
Agonistic behaviour is placed on a continuum from attack to fleeing. The factors that affect which of these conflicting tendencies is favoured and by how much are:
These phenomena can be studied in the context of threat displays, for example in birds. There are a number of possible interpretations of these displays:
Darwin thought that threat displays were true expressions of emotion. However, it is clear that deception is important to success in threatening; but it is probably more useful to analyse the phenomenon in terms of negotiation. Overall, the subject of threat postures and how they evolved, along with the conspicuous display structures often involved, remains a bit of a puzzle.
Ethological analogies are often used to explain human aggression, involving observations such as:
One should be wary of such analogies - human aggression is different. Aggression in children is sometimes classified as follows:
There are many schemes for classification of aggression in adults. One involves identifying a balance between propensities for aggressiveness, acquisitiveness and assertiveness. But none works really well.
The manifestation of aggressive behaviour is the result of in interplay between ontogenetic factors, predisposing factors and eliciting factors.
Family influences on the development of aggression include the following:
Regarding the last of these, the following model has been found useful:
A balance between strong control and warmth is the basis of minimising aggressive behaviour.
Extra-familial influences include:
Predisposing factors include:
Eliciting factors include:
Looking at aggression within families, some factors in child abuse are:
Family violence is influenced by:
There is good evidence that the likelihood of violence is transferred across the generations.
Returning to the issue of what factors are at work at different levels of social complexity, it is clear that
which makes a nonsense of the division of the behavioural sciences into discrete areas.
Aggression within groups is often status related and coalitions, especially with relatives, are often crucial.
A human group is defined as:
‘‘A collection of individuals who see themselves as interdependent and have established a group norm which distinguishes them from members of other groups.’’
The consequences of group formation are an accentuation of perceived in-group similarities and enhancement of group cohesiveness. Individuals strive for a coherent world view, are attracted to people who agree with their views and develop a group loyalty. Members tend to
Aggression between small groups is affected by:
So what does the analysis of human aggression tell us about the issue of international war? Professor Hinde argued that individual aggression has very little to do with the behaviour of soldiers in war time and that biologists have very little to contribute to the discussion. War must be seen as an institution that creates roles in the same way as other institutions:
| Institution | Roles |
| Marriage | Husband, wife |
| Parliament | Prime Minister, cabinet minister, MPs, voting public |
| War | Politicians, soldiers, generals, transport workers, munitions workers, medics |
So, we need to see what it is that contributes to the acceptance of war as an institution.
Everyday factors are:
Pervasive cultural factors are:
The distinctions between patriotism and nationalism are as follows:
| Patriotism | Nationalism |
| love of one's own nation | national superiority |
| much less hawkish about nuclear weapons | more hawkish about nuclear weapons |
| willing to risk one's life for one's country | less willing to risk one's life for one's country |
Propaganda typically attemps to strengthen the enemy image by reinforcing the following tendencies:
Finally Professor Hinde stressed that war is an institutionalised set of institutions - military, industrial and scientific amongst others. He hoped that he had emphasised that one can’t make blanket statements about aggression - it is necessary to establish what sort of aggression is being talked about at each level and what factors are relevant at each level. Society needs to achieve just the right balance between co-operation within groups and competition between groups.
Robert Peel