Physiologic and motor conditioning and generalization in children with minimal brain dysfunction

Twenty-six children diagnosed as having minimal brain dysfunctions (MBD) were compared with 26 controls in a conditinoing and generalization procedure. Skin resistance, heart rate, and muscle action potentials were monitored throughout. Success involved learning which of two tones signalled the accessibility of a penny. Whereas 92 per cent of controls reached the criterion of five successive correct responses, only 62 per cent of MBD’s did. Further, a third of the MBD’s were so maladaptive as to force procedural variations, while only a few minor irregularities occurred with the controls. Quality of performance was related to age, intelligence, and ability to discriminate and remember tones. Controls were more physiologically reactive than MBD’s, especially in skin resistance. Physiologic differentiation of the two tones was significant in both groups of children and appeared concurrently with motor differentiation. The only evidence of physiologic generalization was in the SR data of controls. The possibility that defective arousal structures, or defective coupling of arousal structures and other perceptual and motor structures, could account for the decreased physiologic reactivity, short attention spans, and poor concentration ofsome MBD’s is discussed. This research, in conformity with other laboratory studies of the brain, indicates that motivational as well as cognitive defects may be organically based.