Human place and response learning: navigation strategy selection, pupil size and gaze behavior.

In this study, we examined the cognitive processes and ocular behavior associated with on-going navigation strategy choice using a route learning paradigm that distinguishes between three different wayfinding strategies: an allocentric place strategy, and the egocentric associative cue and beacon response strategies. Participants approached intersections of a known route from a variety of directions, and were asked to indicate the direction in which the original route continued. Their responses in a subset of these test trials allowed the assessment of strategy choice over the course of six experimental blocks. The behavioral data revealed an initial maladaptive bias for a beacon response strategy, with shifts in favor of the optimal configuration place strategy occurring over the course of the experiment. Response time analysis suggests that the configuration strategy relied on spatial transformations applied to a viewpoint-dependent spatial representation, rather than direct access to an allocentric representation. Furthermore, pupillary measures reflected the employment of place and response strategies throughout the experiment, with increasing use of the more cognitively demanding configuration strategy associated with increases in pupil dilation. During test trials in which known intersections were approached from different directions, visual attention was directed to the landmark encoded during learning as well as the intended movement direction. Interestingly, the encoded landmark did not differ between the three navigation strategies, which is discussed in the context of initial strategy choice and the parallel acquisition of place and response knowledge

The use of landmark-based wayfinding strategies across the adult lifespan

Individuals can employ different landmark-based wayfinding strategies to acquire spatial knowledge and support navigation. Allocentric strategy use is associated with a cognitive representation of a learned environment that allows flexible navigation, while egocentric strategy use is associated with uni-directional knowledge that only supports accurate navigation in tasks that involve reproducing learned behaviours. While many studies have investigated strategy use during navigation, how strategy use develops during spatial learning remains under- researched. Therefore, this thesis primarily investigated the processes underlying strategy selection. Participants’ strategy preference during various navigation tasks, including a novel strategy assessment paradigm developed specifically for this research, revealed that individuals adopt the most accurate strategy available – be it allocentric or egocentric – in accordance with the demands of the concurrent navigation task. Interestingly, when allocentric knowledge was required for accurate navigation, participants initially employed a suboptimal egocentric strategy before switching to an allocentric strategy, suggesting that egocentric knowledge precedes allocentric knowledge. Finally, participants were not subject to performance-related decrements associated with the effort of switching strategies. Interestingly, during spatial learning, participants acquired spatial knowledge related to alternative strategies, and selectively encoded landmarks that were compatible with the use of multiple strategies, which may explain why switching wayfinding strategies is cognitively efficient. This thesis also investigated the effects of aging on strategy selection. Strategy preference changes across the adult lifespan, with decreasing allocentric strategy use primarily attributed to reduced hippocampal function, and impaired egocentric strategy use associated with age-related learning and memory deficits. Analysis revealed that older adults exhibited a task-independent preference for egocentric strategy use, and therefore experienced difficulty with tasks that required allocentric knowledge. However, when egocentric strategy use most efficiently supported accurate navigation, younger and older adults performed similarly, suggesting that egocentric strategy use is largely unaffected by aging. Finally, age differences in strategy preference and spatial learning were observed when the most efficient route learning strategy differed between decision points, supporting findings of increasing susceptibility to switching costs with age. In summary, young adults flexibly employ a variety of strategies to optimise navigational efficacy, while older adults' strategy choices are affected by age-related difficulties with allocentric strategy use and increased vulnerability to strategy switching costs

The relationship between wayfinding performance, spatial layout and landmarks in virtual environments

Environmental factors, including landmarks that affect people’s wayfinding performance in unfamiliar environments have been discussed in a great number of studies. However, there is still no consensus on the factors that shape people’s performance or what makes a landmark preferable during wayfinding. Hence, this study aims to understand the impact of different spatial layouts, environmental conditions and landmarks on people’s wayfinding performance, and the factors that make landmarks salient. Sea Hero Quest (SHQ), an online game that has been played by more than 4.3 million people from 2016 to date, is selected as a case study to investigate the impact of different environments and other factors, in particular landmarks. Forty-five wayfinding levels of SHQ are analysed and compared using Geographic Information System (GIS) and Space syntax axial, segment and visibility graph analyses. A cluster analysis is conducted to examine the relationship between levels. Varying conditions associated with landmarks, weather and maps were taken into consideration. In order to investigate the process of selecting landmarks, visual, structural (whether landmarks are global or local) and cognitive saliency are analysed using web-based surveys, saliency algorithms and the visibility of landmarks. Results of this study show that the complexity of layouts plays a major role in wayfinding; as the complexity of layout increases, so does the time taken to complete the wayfinding task. Similarly, the weather condition has an effect; as the weather becomes foggy and visibility decreases, the time taken to complete the wayfinding task increases. It is discovered that landmarks that are visible for more than 25% of a journey can be defined as global landmarks whereas the rest can be defined as local landmarks. Findings also show that landmarks that are visually salient (objects with a unique colour and size) and structurally salient (objects that are closer to people) are registered more by people in unfamiliar environments. This study contributes to the existing literature by exploring the factors that affect people’s wayfinding performance by using the largest dataset in the field (so providing more accurate results), focusing on 45 different layouts (while current research studies mostly focus on one or two different layouts), by proposing a threshold to distinguish global and local landmarks, and analysing visual, structural and cognitive saliency through various measures

Moving through language: a behavioural and linguistic analysis of spatial mental model construction

Over the past few decades, our understanding of the cognitive processes underpinning our navigational abilities has expanded considerably. Models have been constructed that attempt to explain various key aspects of our wayfinding abilities, from the selection of salient features in environments to the processes involved in updating our position with respect to those features during movement. However, there remain several key open questions. Much of the research in spatial cognition has investigated visuospatial performance on the basis of sensory input (predominantly vision, but also sound, hapsis, and kinaesthesia), and while language production has been the subject of extensive research in psycholinguistics and cognitive linguistics, many aspects of language encoding remain unexplored. The research presented in this thesis aimed to explore outstanding issues in spatial language processing, tying together conceptual ends from different fields that have the potential to greatly inform each other, but focused specifically on how landmark information and spatial reference frames are encoded in mental representations characterised by different spatial reference frames. The first five experiments introduce a paradigm in which subjects encode skeletal route descriptions containing egocentric (“left/right”) or allocentric (cardinal) relational terms, while they also intentionally maintain an imagined egocentric or allocentric viewpoint. By testing participants’ spatial knowledge either in an allocentric (Experiments 1-3) or in an egocentric task (Experiments 4 and 5) this research exploits the facilitation produced by encoding-test congruence to clarify the contribution of mental imagery during spatial language processing and spatial tasks. Additionally, Experiments 1-3 adopted an eye-tracking methodology to study the allocation of attention to landmarks in descriptions and sketch maps as a function of linguistic reference frame and imagined perspective, while also recording subjective self-reports of participants’ phenomenal experiences. Key findings include evidence that egocentric and allocentric relational terms may not map directly onto egocentric and allocentric imagined perspectives, calling into question a common assumptions of psycholinguistic studies of spatial language. A novel way to establish experimental control over mental representations is presented, together with evidence that specific eye gaze patterns on landmark words or landmark regions of maps can be diagnostic of different imagined spatial perspectives. Experiments 4 and 5 adopted the same key manipulations to the study of spatial updating and bearing estimation following encoding of short, aurally-presented route descriptions. By employing two different response modes in this triangle completion task, Experiments 4 and 5 attempted to address key issues of experimental control that may have caused the conflicting results found in the literature on spatial updating during mental navigation and visuospatial imagery. The impact of encoding manipulations and of differences in response modality on embodiment and task performance were explored. Experiments 6-8 subsequently attempted to determine the developmental trajectory for the ability to discriminate between navigationally salient and non-salient landmarks, and to translate spatial relations between different reference frames. In these developmental studies, children and young adolescents were presented with videos portraying journeys through virtual environments from an egocentric perspective, and tested their ability to translate the resulting representations in order to perform allocentric spatial tasks. No clear facilitation effect of decision-point landmarks was observed or any strong indication that salient navigational features are more strongly represented in memory within the age range we tested (four to 11 years of age). Possible reasons for this are discussed in light of the relevant literature and methodological differences. Globally, the results presented indicate a functional role of imagery during language processing, pointing to the importance of introspection and accurate task analyses when interpreting behavioural results. Additionally, the study of implicit measures of attention such as eye tracking measures has the potential to improve our understanding mental representations, and of how they mediate between perception, action, and language. Lastly, these results also suggest that synergy between seemingly distinct research areas may be key in better characterising the nature of mental imagery in its different forms, and that the phenomenology of imagery content will be an essential part of this and future research

Moving through language: a behavioural and linguistic analysis of spatial mental model construction

Over the past few decades, our understanding of the cognitive processes underpinning our navigational abilities has expanded considerably. Models have been constructed that attempt to explain various key aspects of our wayfinding abilities, from the selection of salient features in environments to the processes involved in updating our position with respect to those features during movement. However, there remain several key open questions. Much of the research in spatial cognition has investigated visuospatial performance on the basis of sensory input (predominantly vision, but also sound, hapsis, and kinaesthesia), and while language production has been the subject of extensive research in psycholinguistics and cognitive linguistics, many aspects of language encoding remain unexplored. The research presented in this thesis aimed to explore outstanding issues in spatial language processing, tying together conceptual ends from different fields that have the potential to greatly inform each other, but focused specifically on how landmark information and spatial reference frames are encoded in mental representations characterised by different spatial reference frames. The first five experiments introduce a paradigm in which subjects encode skeletal route descriptions containing egocentric (“left/right”) or allocentric (cardinal) relational terms, while they also intentionally maintain an imagined egocentric or allocentric viewpoint. By testing participants’ spatial knowledge either in an allocentric (Experiments 1-3) or in an egocentric task (Experiments 4 and 5) this research exploits the facilitation produced by encoding-test congruence to clarify the contribution of mental imagery during spatial language processing and spatial tasks. Additionally, Experiments 1-3 adopted an eye-tracking methodology to study the allocation of attention to landmarks in descriptions and sketch maps as a function of linguistic reference frame and imagined perspective, while also recording subjective self-reports of participants’ phenomenal experiences. Key findings include evidence that egocentric and allocentric relational terms may not map directly onto egocentric and allocentric imagined perspectives, calling into question a common assumptions of psycholinguistic studies of spatial language. A novel way to establish experimental control over mental representations is presented, together with evidence that specific eye gaze patterns on landmark words or landmark regions of maps can be diagnostic of different imagined spatial perspectives. Experiments 4 and 5 adopted the same key manipulations to the study of spatial updating and bearing estimation following encoding of short, aurally-presented route descriptions. By employing two different response modes in this triangle completion task, Experiments 4 and 5 attempted to address key issues of experimental control that may have caused the conflicting results found in the literature on spatial updating during mental navigation and visuospatial imagery. The impact of encoding manipulations and of differences in response modality on embodiment and task performance were explored. Experiments 6-8 subsequently attempted to determine the developmental trajectory for the ability to discriminate between navigationally salient and non-salient landmarks, and to translate spatial relations between different reference frames. In these developmental studies, children and young adolescents were presented with videos portraying journeys through virtual environments from an egocentric perspective, and tested their ability to translate the resulting representations in order to perform allocentric spatial tasks. No clear facilitation effect of decision-point landmarks was observed or any strong indication that salient navigational features are more strongly represented in memory within the age range we tested (four to 11 years of age). Possible reasons for this are discussed in light of the relevant literature and methodological differences. Globally, the results presented indicate a functional role of imagery during language processing, pointing to the importance of introspection and accurate task analyses when interpreting behavioural results. Additionally, the study of implicit measures of attention such as eye tracking measures has the potential to improve our understanding mental representations, and of how they mediate between perception, action, and language. Lastly, these results also suggest that synergy between seemingly distinct research areas may be key in better characterising the nature of mental imagery in its different forms, and that the phenomenology of imagery content will be an essential part of this and future research