PitkÄnen, L. An aggression machine. I. The intensity of aggressive defence aroused by aggressive offence. Scand. J. Psychol., 1973, 14, 56–64.‐Sixty 9‐year‐old boys were tested with an aggression machine (PAM) designed by the writer. PAM allows the variation of both S (light) and R (pressing a button) intensities. The stimuli and responses were given the designations of offensive and defensive aggression, respectively. The following main hypotheses were supported: (1) The intensity of impulsive aggressive defence to an aggressive offence was adapted to the intensity of attack. (2) The intensity of aggressive defence was determined by the authority of the attacker, the defence being strongest when the attacker was a person of the same age and status, and least vigorous when the attacker was a figure of authority or a weaker person. (3) The correlations of the intensity of aggressive defence against different attackers depended on the similarity of their social position; the correlations were higher the closer the position.

Abstract.— The subjects consisted of two. matched, extremely aggressive (experimental = ExG and control = CoG) groups of twelve 8–year‐old boys. and of one criterion group (CrG) of extrovert, well‐controlled boys. Video‐tape recording of behaviour was used both in pretest (T1) and post‐test (T2). Between T1 and T2 the ExG was submitted to simulation exercises of 8 lessons given in a period of four weeks. The exercises consisted in social problem solutions on the purely cognitive (imaginary and symbolic) level and in role‐playing (behavioral level). The hypothesis was that the combination of cognitive training and observational learning with the aim of making children realise alternatives to aggression in coping with thwarting situations and their after‐effects. would influence individuals with strong aggressive habits to abandon theiraggressive reactions in favour of more constructive behaviour. As to aggression, the results supported the hypothesis. For constructive behaviour, (1) the ExG maintained the samelevel of control of social behaviour in T1 and T2, while a significant drop occurred in the GoC, and (2) the strategies of problem solution improved significantly in the ExG. In T2, the behaviour of the ExG resembled more closely that of the CoG than the behaviour of the CrG, as hypothesized.

PitkÄnen, L. The stability of aggressive and non‐agressive patterns of behaviour. Scand. Psychol., 1973, 14, 75–77.‐Six extreme groups (overtly aggressive, aggressive‐anxious, anxious, controlled extraverts, balanced controlled, and controlled introverts) had been composed on the basis of peer ratings. The differences between the groups were describable in terms of a two‐dimensional model including the main dimensions “number of overt responses” and “control of behaviour”. Independent teacher ratings after an interval of one year showed that the individual patterns of behaviour adopted for coping with thwarting situations were maintained in spite of the change of class environment.

PitkÄnen, L. An aggression machine. II. Interindividual differences in the aggressive defence responses aroused by varying stimulus conditions. Scand. J. Psychol., 1973, 14, 65–74.‐The subjects, six aggressive and nonaggressive groups of ten 9‐year old boys, selected by rating method, were tested with an “aggression machine” (PAM) constructed by the writer. The varying stimulus conditions included two situations of impulsive aggression and six variations of specified attackers. The results showed that (1) the larger part of the variance of the intensity of aggression in the PAM was accounted for by the situational variations than by interindividual differences in coping with thwarting situations as measured by a rating method. (2) The overtly aggressive boys showed strong discrimination between the situations, while the overtly nonaggressive boys were quite insensitive to situational variations. (3) The intensity of aggressive defence towards a boy of the same age correlated most highly with rated aggressiveness. (4) The latency, duration, and number of aggressive responses did not vary as easily as the intensity according to situations.