Mathematics education researchers have examined the relationship between visualization and mathematics for decades (e.g., Arcavi, 2003; Bishop, 1991; Duval, 1999; Fennema & Tartre, 1985; Presmeg, 1986). Studies have linked spatial visualization ability, such as measured in mental rotation tasks, directly to mathematics self-efficacy (Pajares & Kranzler, 1995; Weckbacher & Okamoto, 2014), which in turn influences mathematics achievement (Casey, Nuttall, & Pezaris, 1997). With the important role that spatial visualization plays in learning mathematics, the recent identification of congenital aphantasia (Zeman, Dewar, & Della Sala, 2015), which is the lack of mental imagery ability, has raised new questions for mathematics education researchers. This study investigated the differences in mental rotation test performance and vividness of spatial imagery between people who have aphantasia and people who do not as a first step toward examining how aphantasia may affect mathematics learning and education. Results confirmed prior aphantasia research showing that there was no significant difference in mental rotation test performance between people with aphantasia and those without aphantasia, despite people with aphantasia reporting significantly lower vividness of spatial imagery. Results also showed that there was less difference in mental rotation test performance between the genders for people with aphantasia, while gender played a significant role in mental rotation test performance for people without aphantasia. People with aphantasia also reported lower self-efficacy in the arts than people without aphantasia. Implications of these results will be discussed within the context of current research, and possible directions for future research will be offered.

Gaining knowledge about methods of memory enhancement is important because it allows us to develop effective strategies and interventions to increase memory performance, optimize cognitive function, and potentially alleviate memory-related challenges such as age-related cognitive decline or memory disorders. This thesis aims to examine the influence of age on self-reported mental imagery (MI) experiences and investigate the potential effects of age and MI on memory training performance using the Method of Loci (MoL). The thesis utilizes data collected from a mobile application from a previous research project conducted at Umeå University. The main findings of this thesis indicate that older adults spent more time on encoding and retrieval tasks, suggesting a decline in cognitive processing speed. However, there was no significant decline in MI ability with age, challenging previous research and suggesting that MI ability may remain relatively stable throughout the lifespan. The findings also suggest that there was no significant correlation between higher MI ability and performance in MoL training. Participants rating themselves as having weaker MI were often achieving high levels in the MoL-training, indicating the potential utilization of alternative cognitive strategies than MI. Spending more time on encoding and retrieval tasks was associated with better performance in MoL training. The findings suggest that age-related declines in processing speed may not necessarily hinder individuals' ability to utilize MoL effectively. However, the findings challenge the idea that MI is such a decisive factor in MoL training and raise questions about which other mechanisms work together for a successful result.

Minnespalats eller locimetoden är en gammal mnemoteknik som använts sedan antikens Grekland och är idag väl använd hos världsmästare i minne. Mnemotekniken går ut på att mentalt visualisera en känd plats, och de saker man ska komma ihåg placeras sedan ut på olika delar av denna plats, vanligtvis i en specifik följd. Det har visat sig vara en strategi som man kan lära sig och bli bättre på och därmed öka mängden information som man kan komma ihåg. En förutsättning för att använda Locimetoden kan tänkas vara att man har förmågan att visualisera. I denna studie ville jag undersöka om personer som har afantasi; saknar förmågan att mentalt visualisera, kan använda Locimetoden. 18 personer deltog i experimentet. Genom en kvasiexperimentell design jämfördes deltagare med låg visualiseringsförmåga mot de med högre visualiseringsförmåga. De fick träna i två veckor på Locimetoden i en digital app där högre nivåer kunde uppnås ju längre sekvenser som de lyckades memorera. Resultatet visade endast signifikanta skillnader när det gällde självskattning för hur svårt det var att använda Locimetoden, i afantasi-gruppen svarade en majoritet att det var svårt i jämförelse med kontrollgruppen som svarade att det var enkelt. Det ska dock noteras att deltagandet var mycket lågt, specifikt för de i afantasi-gruppen men resultatet ger ändå en indikation. Det behövs merforskning för att kunna dra några slutsatser kring personer med afantasi och olika mnemotekniker. / Memory palace or the Method of Loci (MoL) is an old mnemonic technique that has been used since ancient Greece and is today well used by world champions in memory. The mnemonic technique involves mentally visualizing a known place and then placing the things to be remembered in different parts of this place, usually in a specific sequence. It has been shown to be a strategy that one can learn and become better at, thereby increasing the amount of information that one can remember. A prerequisite for using MoL could be that you have the ability to visualize. In this study I wanted to investigate if people who have aphantasia; lacks the ability to mentally visualize, can use MoL. 18 people participated in the experiment. Through a quasi-experimental design, participants with low visualization skills were compared to those with higher visualization skills. They practiced MoL for two weeks in a digital appwhere higher levels could be achieved if they managed to memorize longer sequences. The result only showed significant differences when it came to self-estimation of how difficult it was to use MoL, all participants in the aphantasia group answered that it was difficult compared to the control group who answered that it was easy., it should be noted that participation was very low, specifically for those in the aphantasia group, but the result still gives an indication. More research is needed to draw any conclusions about people with aphantasia and different mnemonic techniques.

Mental images are unique mental representations and the depictive view in the imagery debate states that mental images have similar spatial structures as their corresponding external object. The propositional view, however, contends that beliefs about the external world influence a mental image – also known as the cognitive penetrability theory –, therefore mental images cannot be described in visual terms. People with self-described aphantasia, those considered lacking visual mental images, offer a new opportunity to approach this issue. The current study employed the mental rotation task (MRT), where a three-dimensional object needs to be mentally aligned with another one that is rotated to a different angular position. To test the effects of beliefs on mental images, different instruction conditions were used on the MRT. Twenty-seven participants (21 females, mean age 47 years) with self-described aphantasia completed an online experiment, consisting of the MRT, the Object-Spatial Imagery Questionnaire (OSIQ), and the Vividness of Visual Imagery Questionnaire (VVIQ). While participants scored low on the VVIQ and higher on the spatial items than on the object items of the OSIQ, the key finding was that increasing reaction time with increasing angular disparity on the MRT was not influenced by different instruction types. This suggests that the theory of cognitive penetrability is not applicable on mental rotation in aphantasia, highlighting the importance to revise how mental images (or the lack of them) are understood and described.