intensity scale A sequence of thresholds such that progressively stronger stimuli are needed before the appropriate patterns of behaviour result. These stimuli may be increasingly intensive repetitions of a single stimulus (e.g. a spider that is only slightly hungry does not respond to prey; when rather more hungry it turns toward the prey; when still more hungry it initiates an attack).

intensity scale A sequence of thresholds such that progressively stronger stimuli are needed before the appropriate patterns of behaviour result. These stimuli may be increasingly intensive repetitions of a single stimulus (e.g. a spider that is only slightly hungry does not respond to prey; when rather more hungry it turns toward the prey; when still more hungry it initiates an attack).