This type of planted obligation is a famous psychological principle called "reciprocity."

Sniping works on a simple psychological principle.

Bergson sees an internal psychological principle of development, hence the name of his book, "Creative Evolution."

Moreover, the more closely we attend to it, the more explicitly do we imitate it, by an evident psychological principle.

This is a correct psychological principle, for that matter, even when those practicing it do not fully understand the underlying facts.

There is no uniform psychological principle which determines that the three-headed snake in one story shall become a three-headed man in the next.

Well the important principles in magic are psychological principles, not mechanical principles.

Could parents better train their children if they made use of psychological principles?

Psychological principles verify the proverb that practice makes perfect.

Politicians are invoking the brain to justify arguments more sensibly grounded on social or psychological principles.

Talk to successful physicians and find out what use they make of suggestion and other psychological principles.

Do ideals and motives govern the world, but only as these ideals and motives are themselves produced according to biological or psychological principles?

A few words, however, will make it clear to the scientific mind that her phenomena can be easily accounted for on purely psychological principles, thus:

"If this argument is valid-andits validity is self-evident- it isimpossibletoimagine a case that may not be thus explained on psychological principles."