Dean & Morris (2003) found that systematically manipulating the item type and ratings used on self-report measures of imagery it is possible to access introspections that predict spatial performance.

The question to emerge from the initial study was what aspect of the manipulation caused the predictive value of the new questionnaire over the VVIQ. To investigate, performance on five spatial tests was compared to introspective ratings on the VVIQ (Marks, 1973) and an extended version of the Dean & Morris (2003) imagery questionnaire. It was found that changing the item type and source of the item lead to introspective ratings that predict spatial ability.

Ratings of shapes that are more similar to those used in spatial tests can predict performance compared with ratings of real world objects recalled from long term memory that cannot. The effect of item type leads to the conclusion that there are processes associated with particular items that are unique and at present unexplained. Such findings are difficult to interpret in terms of the structural limitations of present models of the imagery system.

IntroductionThe construct of mental imagery has long been considered a fundamental source of individual differences in spatial ability and performance on spatial tasks (Cooper, 1975 cf. Kosslyn, 1994., Kyllonen, 1996.

, Nisbett & Wlson, 1977., Shephard & Metzler., Paivio, 1970). It is interesting to note therefore how measures based on introspective reports of the conscious experience of imagery had previously found no relationship with performance on spatial tasks in which imagery is thought to play a functional role (Richardson, 1977a., Sheehan & Neisser, 1969).Dean & Morris (2003) suggest that the central problem in imagery research stems from the inability of self-report measures to capture the processes underlying imagery.

Although it is frequently suggested that mental images are related to the solution of spatial problems, none of these imagery measures actually deal with items involved in tests of spatial ability. The images required by the measures almost always hinge on items recalled or constructed from long-term memory (see VVIQ; Marks, 1973., QMI; Betts, 1909, cf. Dean & Morris, 2003) where as spatial tasks require the manipulation of imagined objects, which themselves, are arbitrary and unfamiliar. In line with Dean & Morris (2003) problems with existing measures could thus arise because images evoked from long term memory could possibly be the result of processes independent of those used when perceiving and imagining items required in tests of spatial ability.

Traditionally research has focussed on vividness of imagery as if it were a single ability (Marks, 1973., Sheehan & Neisser, 1969). In conflict however evidence suggests that the use of vividness as a single measure is inherently flawed (Mckelvie, 1995, cited in Dean & Morris, 2003). According to Kosslyn’s (1980, 1994) computational account, imagery is best conceived as a collection of abilities, the end product of which is usually described as “seeing with the minds eye” (Kosslyn, Sukel ; Bly, 1999, p.276). The quasi-pictorial surface images experienced are the result of a number of processes and their influence on the “visual buffer” (Kosslyn, 1994, p.

400).Dean ; Morris (2003) found that by changing the ratings on a newly constructed imagery questionnaire based on the main principles of Kosslyn’s theory (1980, 1994) it was possible to find significant correlations with performance on spatial tests, whereas no correlation was obtained from ratings on the VVIQ. The new ratings captured more of the imagery processes than vividness alone, however the largest change was found to be due to item type imagined by participants, vividness ratings for shapes used in spatial tests correlated significantly with performance on spatial tests, in comparison vividness ratings for items recalled from long term memory did not. Such findings yield sufficient answers as to why previous measures have found no correlation; the large effect of item type suggests that it is central to the predictive ability of the questionnaire.At a closer inspection of the findings however, it should be noted that two dimensions of the items had been changed from those of the VVIQ. The item type (real world objects/scenes vs. line drawings of shapes) and the nature of the item (recalled from long term memory vs. perceived and imagined).

Thus it is not clear from the original study which of these manipulations was central to the predictive ability of the questionnaire.The current experiment aimed put these unsettled issues at rest. An extended version of the imagery questionnaire used in the original study (Dean & Morris, 2003) was employed in order to contrast all possible dimensions of the four variables. Additionally the VVIQ (Marks, 1979) was included to test the predictive ability of the new questionnaire with that of the previously failed measures. In line with Dean & Morris (2003) the current experiment aimed to investigate the relationship between self-reports of imagery based on the newly developed questionnaire and performance on five spatial tests.

Specifically it is the role of the current paper to report on the correlation between the new ratings across different item types with performance on the Comprehensive Ability Battery Spatial Test (CAB-S; Hakstian & Cattell, 1976, cited in Dean & Morris, 2003).MethodDesignThe current experiment employed a correlation design. The independent variables were the individual items and the ratings for the new questionnaire and the VVIQ. There were five dependant variables reflecting a measure of spatial ability; Comprehensive ability battery spatial test (CABS), the Vandenberg test of mental rotation (VAND), visualisation of rotations (VR), visualisation of views (VV) and space relations (SR).ParticipantsAn opportunity sample of 226 undergraduate students volunteered to take part in the experiment as part of their course.

MaterialsThe five spatial tests used in the current experiment were the (CABS) test of mental rotation, the Vandenberg test of mental rotation, the Visualisation of views, the Visualisation of rotation and the Space relations test. The imagery questionnaires selected were the VVIQ (Marks, 1973) and an extended version of the questionnaire used in the study by Dean & Morris (2003). The questionnaire consisted of 14 questions and 8 items. Each item was systematically variated in order to contrast different dimensions of the variables.

Items were manipulated by virtue of a change in either the source of the item (perceived or recalled) or the type of image (everyday image or line drawing).ProcedureThe measures were completed by participants in two sessions with a 1 week interval in between sessions. In the first session participants completed the VVIQ and the new imagery questionnaire, in the second session participants completed the five spatial tests. The spatial tests were completed in the following order: CABS, Vandenberg, Visualisation of rotations, visualisation of views and space relations.Participants were allowed as long as they wanted to complete the VVIQ and the new imagery questionnaire.

Time constraints of 2 minutes were placed on the CABS and the Vandenberg tests, and 12 minutes each for the remaining spatial tests.