A vulgar man often scratches his head when perplexed in mind; and I
believe that he acts thus from habit, as if he experienced a slightly
uncomfortable bodily sensation, namely, the itching of his head,
to which he is particularly liable, and which he thus relieves.
Another man rubs his eyes when perplexed, or gives a little cough
when embarrassed, acting in either case as if he felt a slightly
uncomfortable sensation in his eyes or windpipe.[6]

From the continued use of the eyes, these organs are especially
liable to be acted on through association under various states
of the mind, although there is manifestly nothing to be seen.
A man, as Gratiolet remarks, who vehemently rejects
a proposition, will almost certainly shut his eyes or turn
away his face; but if he accepts the proposition, he will
nod his head in affirmation and open his eyes widely.
The man acts in this latter case as if he clearly saw the thing,
and in the former case as if he did not or would not see it.
I have noticed that persons in describing a horrid sight often
shut their eyes momentarily and firmly, or shake their heads,
as if not to see or to drive away something disagreeable;
and I have caught myself, when thinking in the dark of a
horrid spectacle, closing my eyes firmly. In looking suddenly
at any object, or in looking all around, everyone raises
his eyebrows, so that the eyes may be quickly and widely opened;
and Duchenne remarks that[7] a person in trying to remember
something often raises his eyebrows, as if to see it.
A Hindoo gentleman made exactly the same remark to Mr. Erskine
in regard to his countrymen. I noticed a young lady earnestly
trying to recollect a painter's name, and she first looked
to one corner of the ceiling and then to the opposite corner,