PROCESO ANALÍTICO JERÁRQUICO (AHP)

The multiple regression results revealed that 55.5% of the variance (R2 _{= .569) is}

explained by the predictors digit span forward and Corsi forward, F (2,64) = 40.97, MSE = 529.686, p < .001 (see table 4.).

Table 4: Results of the final stepwise multiple regression model for the mental rotation performance based on the following predictors: gender, age in months, ball skills, manual dexterity, balance, total motor score, Corsi backward, Corsi forward, digit span forward and backward, CPM are depicted.

Predictor ß T p

Digit span forward .600 6.001 < .01

Corsi forward .234 2.341 < .05 Gender .070 .792 > .25 Age .133 1.139 > .25 Ball skills .125 1.452 > .05 Manual dexterity .077 .816 > .25 Balance .088 .926 > .25

Total motor score .129 1.364 > .05

Corsi backward .039 .336 > .25

Digit span backward .173 1.151 > .25

6.3 Discussion

The relationship between mental rotation ability, working memory, and motor ability was investigated in this study.

A high correlation of the two working memory tests and mental rotation task as well as the working memory tests, balance, and mental rotation was shown. The correlation between balance and the PRT is in line with the study of Jansen and Heil (2010), who found a correlation between PRT and coordination, and was reproduced and expanded in this study for children as young as 3 and 4 years of age. Children with higher scores in the PRT performed better on the balance tasks. This study goes beyond that of Jansen and Heil (2010), because it was found that, in addition to motor ability, working memory is an important component of the mental rotation processes. Interestingly, when separating the children in two age groups, the motor effect was prominent in the younger age group, but not in the older one. For sure, this has to be taken with caution, because the number of participants was quite low in each age group. However, at least it gives a hint that there might be a change in the importance of motor processes in mental rotation in childhood. This is in line with the study conducted by Frick et al. (2009), who showed the importance of motor processes only in younger children. However, the results are contradictory to the study of Krüger and Krist (2009a). They investigated mental rotation using pictures of body parts and found that mental rotation ability was correlated to motor abilities for 7-year-old children and adults. But not for children aged 5-6 years. Our study revealed also that working memory processes do play a role within the mental rotation paradigm as young as 3-4 years of age. This is a new result, which deserves further attention. Since the separation in two age groups is limited due to the low number of participants in each group, the focus of the discussion is dedicated to the overall analysis.

Until now, evidence for the relationship between mental rotation and working memory has already been found using psycho-physiological methods (Heil et al., 1998; Band & Miller, 1997) and imaging technology (Anguera et al., 2010; Jordan et al., 2001; Suchan et al., 2006). However, to our knowledge, this is one of the first studies to find this connection on a behavioral level. As our results show when analyzing the data for all children, the performance on the test for the visuospatial sketchpad (Corsi forward) and the phonological loop (digit recall forward) are related to mental rotation:

children who performed better in working memory tasks showed better results in the PRT. This helps to clarify the relationship between working memory and mental rotation.

This involvement of working memory in mental rotation is in agreement with the findings of Hyun and Luck (2007), who examined the visual working memory during a mental rotation task with the assumption that storage of an object is needed to perform a mental rotation task. Using letters as stimuli, they found an interaction between mental rotation performance and the object working memory, but no involvement of the spatial working memory. This result supports the hypothesis of Carpenter et al. (1999) that during mental rotation the dorsal and ventral streams are activated and that the ventral stream is involved with storage, while the dorsal stream is involved with mental rotation. This separation of the processes of the visuospatial sketchpad is in line with the suggestion of the results of Bruyer and Scailquin (1998). They suggested that there are two subsystems in the visuospatial sketchpad, namely one that passively stores visuospatial information and one that recapitulates visuospatial information. Furthermore, their results showed that the interference of the visuospatial sketchpad decreased with increasing task complexity. Their results indicate that the visuospatial sketchpad is involved in at least two substages of mental rotation: first the rotated image is stored and in a later step this image is compared to the standard image.

As the separation of the two slave systems is stated in literature (Baddeley, 1992, 2000; Bruyer & Scailquin, 1998), the present study indicates that the involvement of the phonological loop in the mental rotation process needs further attention, at least concerning preschool children.

According to Gathercole et al. (2004), the involvement of the phonological loop in the processes of mental rotation might be that the phonological loop recodes non- phonological inputs into phonological forms. This is done so that the information can be held in the phonological store and be easily recalled as needed. Since the mental rotation ability was assessed using pictures in this study, the children might have relied on the rehearsal processes of the phonological loop to solve the mental rotation task. This might explain the connection between the digit span forward test and the mental rotation. As this test measures the storage capacity of one slave system of working memory, it is assumed that during mental rotation the rotated

object needs to be stored in order to compare it to the shown stimuli. Normally, the phonological loop and its rehearsal processes are used for storing familiar objects. The objects used in this study were considered familiar objects and this process becomes more important with age. In young children, the phonological loop is not fully developed. Therefore, it is possible that they rely more heavily on the processes of the visuospatial sketchpad (Gathercole et al., 2004). However, this theory is not supported by our study, since we did find a correlation between the phonological loop and mental rotation for children from 3-6 years old.

Further evidence for the involvement of the phonological loop in mental rotation abilities might be found in studies with dyslexic children. Dyslexia is a reading disability, the cause of which is still controversially discussed. It is still not clear whether it can be attributed to phonological deficits or if the problem lies elsewhere (Démonet, Taylor, & Chaix, 2004; Vidyasagar & Pammer, 2010). If the involvement of the phonological loop is important for mental rotation, as it is suggested in this study and in the study of Rüssler, Scholz, Jordan, and Quaiser-Pohl (2005), a study which demonstrates impaired mental rotation ability in children with dyslexia (irrespective of the stimulus material used), could help to further define the role of the phonological loop in mental rotation as well as the underlying cause of dyslexia.

To our knowledge, this is the first study which has investigated the relationship between working memory processes, motor ability, and mental rotation performance. Also, it is the first study that has shown that the connection between motor ability and mental rotation diminishes when working memory processes can be taken into account. Continued investigation into the relationship between mental rotation and working memory is needed to understand the underlying processes involved. Furthermore, the relationship between motor ability, working memory, and mental rotation might also be considered in executive function research. Since working memory is one aspect of the executive functions of cognitive abilities and has been linked to motor abilities on both a behavioral and a neuroanatomical level (Pangelinan et al., 2011), the executive functions may play an important role in the relationship between these different aspects. Wassenberg et al. (2005) already indicated a relationship between attention, executive functioning, and motor performance. Future research must investigate how all of these aspects influence mental rotation and cognition under special attention of age.

The presented results and discussion of both this experiment and the other two experiments are discussed in a wider context in the final concluding discussion. The presented results and discussion of this experiment as well as the results and discussion of the other two experiments are discussed in a broader understanding in the final discussion. Thereby, an extended point of view regarding the topic of mental rotation and the underlying processes is considered.