Table 1.

Comparison of mental model theory and the theory of mental images.

	Mental model theory		Mental imagery
	Mental model	Mental image	Spatial mental image	Visual mental image
Structure	Structurally analogical to problem domain (Johnson-Laird, 1998); amodal or multi-modal (Knauff and Johnson-Laird, 2002); spatio-analogical (Knauff et al., 2003)	No concrete statements about structure are made	Spatio-analogical (Kosslyn et al., 2006); described as configuration of points in space (Kosslyn, 1994, p. 324)	Spatio-analogical, i.e., “depictive” (Kosslyn, 1994)
Anatomical localization	Parietal lobe plays a key role in mental model reasoning (Knauff et al., 2003)	Occipital lobe (specifically V2) (Knauff et al., 2003)	Posterior parietal lobe (Kosslyn et al., 2006)	Topographically organized areas of the occipital lobe (the visual buffer) (Kosslyn and Thompson, 2003)
Relationship between the two representations	Mental images are special cases of mental models (Johnson-Laird, 1998). Reasoning is realized with mental models (Knauff and Johnson-Laird, 2002)		Spatial mental images (object maps) set spatial parameters, e.g., location, size, and orientation for the shapes represented in a visual mental image (Kosslyn et al., 2006); a visual mental image represents a “visualized” part of a spatial mental image (Kosslyn et al., 2006, p. 138)
Content	Abstract relations, e.g., ownership, “worse than,” and spatial relations, e.g., orientation, distance, topology (for an overview, see Johnson-Laird, 2001)	Visual information, e.g., visual configuration seen from a certain perspective (Johnson-Laird, 1998)	Spatial properties, e.g., location, size, orientation (Kosslyn et al., 2006)	Visual/object properties, e.g., shape information, color, depth (Kosslyn et al., 2006)
Processes	Model construction, model inspection, model variation (Johnson-Laird and Byrne, 1991)	Mental images can be constructed from visualizable parts of an underlying mental model (Johnson-Laird, 1998); insights from image manipulation are reinterpreted within the underlying mental model (Johnson-Laird, 1998)	Construction, inspection, maintenance, manipulation (Kosslyn, 1994); inspection (including inference of new information) of visual mental images is explained by employing processes of visual perception on the content of the visual buffer; inference from spatial mental images is possible
Typical experimental paradigms	Different (often spatial) syllogisms without any references to visual imagination (for an overview, see Johnson-Laird, 2001)	Syllogisms with visual but non-spatial relations, e.g., “dirtier than” (Knauff and Johnson-Laird, 2002)	To our knowledge there is no paradigm to specifically induce spatial mental images	“Imagine,” “try to see mentally” (e.g., Kosslyn, 1973, 1980; Chambers and Reisberg, 1985; Borst et al., 2006)
Phenomena unique to theory	Preferred mental models (e.g., Jahn et al., 2007)		Spontaneous eye movements corresponding to the processed content in mental images (e.g., Johansson et al., 2006, 2012)