Mediating variables are prominent in psychological theory and research. A mediating variable transmits the effect of an independent variable on a dependent variable. Differences between mediating variables and confounders, moderators, and covariates are outlined. Statistical methods to assess mediation and modern comprehensive approaches are described. Future directions for mediation analysis are discussed.

Humans, being highly social creatures, rely heavily on the ability to perceive what others are doing and to infer from gestures and expressions what others may be intending to do. These perceptual skills are easily mastered by most, but not all, people, in large part because human action readily communicates intentions and feelings. In recent years, remarkable advances have been made in our understanding of the visual, motoric, and affective influences on perception of human action, as well as in the (...) elucidation of the neural concomitants of perception of human action. This article reviews those advances and, where possible, draws links among those findings.Acronyms and DefinitionsApparent motion: perception of smooth motion from brief, successive exposures of static imagesChameleon effect: tendency for people to mimic the actions of others without even knowing itCommon coding principle: theory that perceiving and acting share common mental representationsDynamic noise: an array of randomly positioned dots that can camouflage perception of PL animations when the noise dots are sufficiently denseEvent-related potential : electrical brain activity registered from the scalpExtrastriate body area : brain region activated when a person views a human body or body partsFunctional magnetic resonance imaging : widely used technique that reveals brain activation patterns based on hemodynamic responses to neural activityInversion effect: difficulty of perceiving PL animations when they are shown upside downKinematics: analysis of the motions of objects without regard to the forces producing themMirror neurons: brain cells responsive when an animal engages in an activity or when it watches another animal engaged in that activityPoint-light animations: biological activity portrayed by small light tokens placed on the major body parts of an actorPositron emission tomography : brain imaging technique that uses radioactively labeled tracers to allow visualization of active brain areasSpatiotemporal jitter: means of degrading perception of PL animations, where the relative timing and positions of the moving dots are perturbedSuperior temporal sulcus : region of the cortex the posterior portion of which contains neurons selectively responsive to human activityTemplate-matching model: theory that perception of biological motion results from concatenation of static views of the bodyTranscranial magnetic stimulation : technique producing a brief disruption of neural processing. (shrink)