In this chapter we shall study somewhat in detail the various types of tendencies classified and described in the previous chapter. Attention wiU be given (a) to their characteristics as mental states, (b) to the physiological processes that occasion them, and (c) to the inherited forms of behavior by which they are expressed. In a later chapter, there wiU be some discussion of acquired forms of behavior which result from various tendencies.
PHYSIOLOGICAL TENDENCIESAttention wiU be given, first, to the nature and expressions of physiological tendencies.
Tendencies as Subjective Responses
How Tendencies AriseThe term tendency, as we have previously defined it, implies a subjective state, process, or activity that prompts the individual to act. Because they prompt, lead, or motivate the organism to act in a vigorous manner, tendencies are also caUed urges, cravings, motives, drives, and desires. The problem immediatdy confronting us now is that of showing how these states or processes arise. In order to do this, let us consider the foUowing stimulus-response events:
s,
Bodily Condition
1, "Empty cdls' 2, Cdl poisons
Si(S,) Visceral Activity
Contraction of stomach wdls Muscdar tensk>ns ^s(S,) Consciotts StateSensation, fedings, "hunger" "Fatigue"
Somatic ResponsesCrying, eating, etc.
Relaxing, resting, playing, etc 143
EDUCATIONAL PSYCHOLOGYThe events diagrammed above seem to occur when we "fed" hungry or fatigued, these being selected as examples of physiological tendencies in general, Reading Example 1 across the page, Si is the initial stimulus preceding hunger. It is represented as "empty cells" or body ceUs depleted of their storedup energy. This condition, usuaUy described as a tissue need, leads to Ri, a visceral activity consisting of relativdy intense stomach contractions. Though this is a response to Si, it serves as a stimulus to the various receptors in the stomach walls, S2, which initiate nerve impulses that give rise to the conscious state we call "hunger." In reality this state is a complex group of sensations and feelings, the conscious state designated as Rg. Because of the prompting or motivating character of this state it serves as a stimulus, S3, to arouse the organism to action, Rg. This activity is somatic, overt, or objective, consisting of various forms of bdiavior, from the crying of infants to the eating activities or work of the adult.Example No. 2 suggests how fatigue arises. This is an example of tendencies due to general or widespread bodily conditions rather than to definitdy localized areas, as is the case in hunger. Fatigue, as suggested under Si, is probably caused by the presence of certain poisons, chiefiy lactic acid, which are found in the muscles and nerve centers after prolonged vigorous activity. The poisons appear as a result of chemical action which takes place in the individual cdls when they are overworked. Fatigue, similarly to hunger, is experienced consciously as a group of sensations and feelings produced by strains and inhibitory effects of poisons in the muscles. T...
