Imagination, [66].

Imitation, [236], [282].

Inclination, [126].

Individual differences, [8], [10], [28], [82], [125], [129], [199], [222].

Industrial experiments, [67].

Industry, [59], [160], [191].

Inhibition, [84], [162], [176], [203].

Injuries, [213].

Intelligence, [102].

Interest, [194].