_Images._ Revived sensations, simpler than ideas. _Imitation._ Acting as we see others act. _Impulse._ Tendency to action. _Individualistic instincts._ Those instincts which more immediately serve individual survival. _Individual differences._ The mental and physical differences between people. _Inherited nature._ Those aspects of one's nature due directly to heredity. _Instincts._ Definite responses produced by definite stimuli through hereditary connections in the nervous system. _Intellectual habits._ Definite fixed connections between ideas; definite ways of meeting typical thought situations. _Intensity._ The amount or strength of a sensation or image, how far it is from nothing. _Interest._ The aspect given to experience or thinking by attention and pleasure. _Learning._ Establishing new bonds or connections in the nervous system; acquiring habits; gaining knowledge. _Memory._ The retention of experience; retained and reproduced experience. _Mental set._ Mental attitude or disposition. _Mind._ The sum total of one's conscious states from birth to death. _Nerve-path._ The route traversed by a nerve-stimulus or excitation. _Original nature._ All those aspects of mind and body directly inherited. _Perceive._ To be aware of a thing through sensation. _Perception._ Awareness of a thing through sensation or a fusion of sensations. _Plasticity._ Modifiability, making easy the formation of new bonds or nerve-connections. _Presupposition._ A theory or hypothesis on which an argument or a system of arguments or principles is based. _Primary._ First, original, elementary, perceptive experience as distinguished from ideational experience. _Reaction._ The action immediately following a stimulus and produced by it. _Reasoning._ Thinking to a purpose; trying to meet a new situation. _Reflex._ A very simple act brought about by a stimulus through an hereditary nerve-path. _Response._ The act following a stimulus and produced by it. _Retention._ Memory; modification of the nervous system making possible the revival of experience. _Science._ Knowledge classified and systematized. _Sensation._ Primary experience; consciousness directly due to the stimulation of a sense organ. _Sense._ To sense is to have sensation, to perceive. A sense is a sense organ or the ability to have sensation through a sense organ. _Sense organ._ A modified nerve-end with accompanying apparatus or mechanism making possible a certain form of stimulation. _Sensitive._ Capable of giving rise to sensation, or transmitting a nerve-current. _Sensitivity._ Property of, or capacity for being sensitive. _Sensory._ Relating to a sense organ or to sensation. _Situation._ The total environmental influences of any one moment. _Socialistic instincts._ The instincts related more directly to the survival of a social group. _Stimulation._ The setting up of a nerve process in a sense organ or in a nerve tract. _Stimulus._ That which produces stimulation.