We can understand why the young are much more affected than the old； and women more than men； and why the opposite sexes especially excite each other's blushes。 It becomes obvious why personal remarks should be particularly liable to cause blushing； and why the most powerful of all the causes is shyness； for shyness relates to the presence and opinion of others； and the shy are always more or less self…conscious。 With respect to real shame from moral delinquencies； we can perceive why it is not guilt； but the thought that others think us guilty； which raises a blush。 A man reflecting on a crime committed in solitude； and stung by his conscience； does not blush； yet he will blush under the vivid recollection of a detected fault； or of one committed in the presence of others； the degree of blushing being closely related to the feeling of regard for those who have detected； witnessed； or suspected his fault。
Breaches of conventional rules of conduct； if they are rigidly insisted on by our equals or superiors； often cause more intense blushes even than a detected crime； and an act which is really criminal； if not blamed by our equals； hardly raises a tinge of colour on our cheeks。 Modesty from humility； or from an indelicacy； excites a vivid blush； as both relate to the judgment or fixed customs of others。
From the intimate sympathy which exists between the capillary circulation of the surface of the head and of the brain； whenever there is intense blushing； there will be some； and often great； confusion of mind。 This is frequently accompanied by awkward movements； and sometimes by the involuntary twitching of certain muscles。
As blushing； according to this hypothesis； is an indirect result of attention； originally directed to our personal appearance； that is to the surface of the body； and more especially to the face； we can understand the meaning of the gestures which accompany blushing throughout the world。 These consist in hiding the face； or turning it towards the ground； or to one side。 The eyes are generally averted or are restless； for to look at the man who causes us to feel shame or shyness； immediately brings home in an intolerable manner the consciousness that his gaze is directed on us。 Through the principle of associated habit； the same movements of the face and eyes are practised； and can； indeed； hardly be avoided； whenever we know or believe that； others are blaming； or too strongly praising； our moral conduct。 CHAPTER XIV。
CONCLUDING REMARKS AND SUMMARY。
The three leading principles which have determined the chief movements of expressionTheir inheritanceOn the part which the will and intention have played in the acquirement of various expressions The instinctive recognition of expressionThe bearing of our subject on the specific unity of the races of manOn the successive acquirement of various expressions by the progenitors of man The importance of expressionConclusion。
I HAVE now described； to the best of my ability； the chief expressive actions in man； and in some few of the lower animals。 I have also attempted to explain the origin or development of these actions through the three principles given in the first chapter。 The first of these principles is； that movements which are serviceable in gratifying some desire； or in relieving some sensation； if often repeated； become so habitual that they are performed； whether or not of any service； whenever the same desire or sensation is felt； even in a very weak degree。
Our second principle is that of antithesis。 The habit of voluntarily performing opposite movements under opposite impulses has become firmly established in us by the practice of our whole lives。 Hence； if certain actions have been regularly performed； in accordance with our first principle； under a certain frame of mind； there will be a strong and involuntary tendency to the performance of directly opposite actions； whether or not these are of any use； under the excitement of an opposite frame of mind。
Our third principle is the direct action of the excited nervous system on the body； independently of the will； and independently； in large part； of habit。 Experience shows that nerve…force is generated and set free whenever the cerebro…spinal system is excited。 The direction which this nerve…force follows is necessarily determined by the lines of connection between the nerve…cells； with each other and with various parts of the body。 But the direction is likewise much influenced by habit； inasmuch as nerve…force passes readily along accustomed channels。
The frantic and senseless actions of an enraged man may be attributed in part to the undirected flow of nerve…force； and in part to the effects of habit； for these actions often vaguely represent the act of striking。 They thus pass into gestures included under our first principle； as when an indignant man unconsciously throws himself into a fitting attitude for attacking his opponent； though without any intention of making an actual attack。 We see also the influence of habit in all the emotions and sensations which are called exciting； for they have assumed this character from having habitually led to energetic action； and action affects； in an indirect manner； the respiratory and circulatory system； and the latter reacts on the brain。 Whenever these emotions or sensations are even slightly felt by us； though they may not at the time lead to any exertion； our whole system is nevertheless disturbed through the force of habit and association。 Other emotions and sensations are called depressing； because they have not habitually led to energetic action； excepting just at first； as in the case of extreme pain； fear； and grief； and they have ultimately caused complete exhaustion； they are consequently expressed chiefly by negative signs and by prostration。 Again； there are other emotions； such as that of affection； which do not commonly lead to action of any kind； and consequently are not exhibited by any strongly marked outward signs。 Affection indeed； in as far as it is a pleasurable sensation； excites the ordinary signs of pleasure。
On the other hand； many of the effects due to the excitement of the nervous system seem to be quite independent of the flow of nerve…force along the channels which have been rendered habitual by former exertions of the will。 Such effects； which often reveal the state of mind of the person thus affected； cannot at present be explained； for instance； the change of colour in the hair from extreme terror or grief； the cold sweat and the trembling of the muscles from fear； the modified secretions of the intestinal canal；and the failure of certain glands to act。
Notwithstanding that much remains unintelligible in our present subject； so many expressive movements and actions can be explained to a certain extent through the above three principles； that we may hope hereafter to see all explained by these or by closely analogous principles。
Actions of all kinds； if regularly accompanying any state of the mind； are at once recognized as expressive。 These may consist of movements of any part of the body； as the wagging of a dog's tail； the shrugging of a man's shoulders； the erection of the hair； the exudation of perspiration； the state of the capillary circulation； laboured breathing； and the use of the vocal or other sound…producing instruments。 Even insects express anger； terror； jealousy； and love by their stridulation。 With man the respiratory organs are of especial importance in expression； not only in a direct； but in a still higher degree in an indirect manner。
Few points are more interesting in our present subject than the extraordinarily complex chain of events which lead to certain expressive movements。 Take； for instance； the oblique eyebrows of a man suffering from grief or anxiety。 When infants scream loudly from hunger or pain； the circulation is affected； and the eyes tend to become gorged with blood： consequently the muscles surrounding the eyes are strongly contracted as a protection： this action； in the course of many generations； has become firmly fixed and inherited： but when； with advancing years and culture； the habit of screaming is partially repressed； the muscles round the eyes still tend to contract； whenever even slight distress is felt： of these muscles； the pyramidals of the nose are less under the control of the will than are the others and their contraction can be checked only by that of the central fasciae of the frontal muscle： these latter fasciae draw up the inner ends of the eyebrows； and wrinkle the forehead in a peculiar manner； which we instantly recognize as the expression of grief or anxiety。 Slight movements； such as these just described； or the scarcely perceptible drawing down of the corners of the mouth； are the last remnants or rudiments of strongly marked and intelligible movements。 They are as full of significance to us in regard to expression； as are ordinary rudiments to the naturalist in the classification and genealogy of organic beings。
That the chief expressive actions； exhibited by man and by the lower animals； are now innate or inherited；that is； have not been learnt by the individual；is admitted by every one。 So little has learning or imitation to do with several of them that they are from the earliest days and throughout life quite beyond our control； for instance； the relaxation of the arteries of the skin in blushing； and the increased action of the heart in anger。 We may see children； only two or three years old； and even those born blind； blushing from shame； and the naked scalp of a very young infant reddens from passion。 Infants scream from pain directly after birth； and all their features then assume the same form as during subsequent years。 These facts alone suffice to show that many of our most important expressions have not been learnt； but it is remarkable that some； which are certainly innate； require practice in the individual； before they are performed in a full and perfect manner； for instance； weeping and laughing。 The inheritance of most of our expressive actions explains the fact that those born blind display them； as I hear from the Rev。 R。 H。 Blair； equally well with those gifted with eyesight。 We can thus also understand the