Psychology

Permanent URI for this collectionhttps://uwspace.uwaterloo.ca/handle/10012/9892

This is the collection for the University of Waterloo's Department of Psychology.

Research outputs are organized by type (eg. Master Thesis, Article, Conference Paper).

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Now showing 1 - 9 of 9

Adapting to Change: The Role of Priors, Surprise and Brain Damage on Mental Model Updating
(University of Waterloo, 2017-04-24) Filipowicz, Alexandre; Anderson, Britt; Danckert, James
To make sense of the world, humans build mental models that guide actions and expectations. These mental models need to be receptive to change and updated when they no longer accurately predict observations from an environment. Although ubiquitous in our everyday lives, research is still uncovering the factors that guide mental model building and updating. A significant challenge arises from the need to characterize how mental models can be both robust to noisy, stochastic fluctuations, while also being flexible to environmental changes. The current thesis explores this trade-off by examining some of the main components involved in updating. Chapter 2 proposes a novel task to measure the influence of prior mental models on the way new information is integrated. Chapter 3 tests the role of unexpected, ‘surprising’ events on our ability to detect changes in the environment. Chapter 4 measures the strategies used to explore new mental models, after a change has been detected, and how specific forms of brain damage influence these strategies. The results from this thesis provide novel insights into the behavioural and neural mechanisms that underlie mental model updating. The last chapter situates these results in existing literature, and suggests directions for future research.
Empirical Adequacy of Ranking Theory: A Behavioural and Theoretical Investigation of Human Uncertainty Representation
(University of Waterloo, 2024-12-12) Go, Hanbin; Anderson, Britt
Measuring and quantifying degrees of belief poses a fundamental challenge, prompting an exploration of how humans navigate uncertainty. This study investigated the application of ranking theory to human belief systems, focusing on its effectiveness in measuring degrees of disbelief across diverse contexts. Experiments 1 and 2 confirmed the reliability of negative ranks as a robust measure of disbelief in uncertain situations where belief might be shaped by personal experiences, societal, and cultural norms. Experiment 3 extended the framework by introducing positive ranks, providing a more comprehensive representation of belief and disbelief, and enabling finer distinctions between disbelief, neutrality, and belief. Experiment 4 examined ranking functions within a dynamic learning environment, demonstrating that ranks aligned more closely with objective probabilities than subjective probabilities when outcomes were clearly defined and consistently observed. Experiments 5 and 6 explored the Ellsberg Paradox, showing that ranking functions reduced ambiguity aversion and provided a more true reflection of participants’ beliefs compared to traditional choice-based methods. Overall, the findings supported ranking theory as an effective framework for understanding belief systems, highlighting its potential to simplify the cognitive demands of uncertainty assessment and reduce biases commonly associated with subjective probability models. This work laid a foundation for future research to explore ranking theory’s application in psychology as a metric for belief and its broader relevance in decision-making processes.
The Interdependence of Attention, Memory, and Performance Based Reward
(University of Waterloo, 2016-06-15) Haskell, Christie Rose Marie; Anderson, Britt
Attention is frequently described as a distinct process with distinct effects, and many researchers have suggested that it has a distinct place in the brain. And yet attention is necessarily entangled with the systems required to complete experimental tasks. Perceptual experiments entangle attentional effects with the properties of perceptual neurons, experiments with transient stimuli entangle the effects of memory with attention, and the early experiments on attention in primates entangled the effects of attention and reward. The purpose of the present thesis, therefore, was to disentangle the effects of attention from the effects of memory and reward on orientation judgements across ten experiments. In all experiments, participants were required to make an orientation judgement from memory of a grating (Chapter 2) or Gabor (Chapters 3 & 4) that appeared briefly on the display. Chapter 2 presents five experiments combining a manipulation of spatial attention using an exogenous luminance cue that was 100%, 80%, or 50% valid with a manipulation of memory consolidation using sequential and simultaneous presentation of two circular gratings. Valid cuing improved performance only when two stimuli appeared together and improved it to the level of performance on uncued sequential trials, whereas invalid cueing always reduced performance. Further, mixture model fitting results indicated that non-predictive cues improved performance by reducing guessing and predictive cues improved performance by increasing precision. These results suggest that, when the demand on memory is greater than a single stimulus, attention is a bottom-up process that prioritizes stimuli for consolidation, thus attention and memory are dependent and synergistic, and that the mechanism by which spatial attention affects precision may be dependent on how we implicitly monitor our environment for statistical regularities. Predictive cues communicate importance about a spatial location and reward is another mechanism that communicates importance, and this is what motivated the experiments presented in Chapter 3. Chapter 3 presents four experiments combining a manipulation of spatial attention via a 50% valid luminance cue with a manipulation of performance-based reward that was communicated to participants by either sound, time, or points. The reward received could be either finely or coarsely related to participant errors and this was manipulated between subjects. Sound and time were ineffective at communicating the reward distribution, but when participants were awarded points, valid cuing improved performance and kurtosis was increased on valid trials only when rewards were finely related to their performance suggesting a dependent relation between reward and attention. One explanation for these results is that reward increases vigilance and attention increases visual search efficiency. The experiment presented in Chapter 4 evaluates this hypothesis. Viewing time was fixed by requiring participants to fixate at the target location to control its offset. We found that under these conditions the effects of cueing and reward were eliminated. Taken together, these results provide evidence that it is not possible to fully disentangle the effects of attention from the system(s) used to perform the task suggesting that spatial attention is not a separate mechanism unto itself, but a property of perception.
Mental Model Updating and Eye Movements
(University of Waterloo, 2020-08-31) Go, Hanbin; Anderson, Britt; Danckert, James
Two studies investigated what eye movements can reveal about how we process surprising information and use it to update mental models. Mental models guide our actions to make decisions in a dynamic environment. Participants made saccades to visual targets presented one at a time, radially, around an invisible perimeter, while their eyes were tracked. Target locations were normally distributed and changed at an unannounced point during the task. In Experiment 1, the distribution changed to one with non-overlapping regions of target locations. Saccadic latencies were slower when targets appeared in areas of low as opposed to high spatial probability. The length of time participants looked at targets, dwell time, increased when unexpected, low probability events occurred. In a second study, the mean of the distribution was held constant, but variance changed in three ways; a narrow-to-wide variance shift; a wide-to-narrow shift, and a no-shift condition. Hence distribution shifts were not as apparent as study 1, especially for the wide-to-narrow variance shift. Participants reported trials on which they perceived a shift in the target distribution, via a mouse click. Participants were poor at determining the distributional shifts. On trials with reported distribution change, participants dwelled on the target longer and were slower to generate saccades. When presented with a narrow-to-wide distribution shift, saccadic latencies were slower for targets from the new wide-distribution (unexpected, low probability), however, no changes were observed in dwell time, suggesting that participants deemed the highly surprising events as random noise with no predictive value for future events, and hence felt no need to update their predictive model. Results suggest that slower saccadic latency reflects surprise, whereas longer dwell time reflects updating of a mental model.
Perception of Probabilities which are Subject to Change
(University of Waterloo, 2022-08-29) Schirmeister, Julia; Anderson, Britt
To navigate stochastic and changing environments, people need to keep track of ongoing probabilities as those probabilities are subject to change. Two distinct theories of mental-model updating are compared. In trial-by-trial updating models, every sample is immediately integrated into a working estimate of the probability. In change-point detection, a single estimate of the probability is maintained until evidence accumulates to reject that model to adapt a new model. Disentangling these theories of updating frequencies has been difficult due to a confound found in previous tasks. Participants have been given their last response as their default response, and this has made it easier for them to maintain the same estimate rather than update it. This favours change-point models. To address whether response-maintenance is due to the extra effort it takes to update a response, participants were separated into two groups. In the Automatic condition, participants were given their old response as default. In the Manual condition, participants were given no default and were asked to generate a new estimate of the probability every trial. While offering a default response was found to partially explain response maintenance in previous tasks, it did not fully explain it. Participants in the Manual group showed spontaneous meticulous response maintenance over long series of trials despite being asked to respond anew every trial. This suggests that the hypothesis-testing strategy developed in the change-point detection literature is a fundamental component of probability estimation and is not an artifact of previous task designs.
The Perceptual Mechanisms of Probability Effects
(University of Waterloo, 2018-04-13) Jabar, Syaheed; Anderson, Britt
Environmental statistics impact human behaviour. The more likely something is to occur, the faster and more accurate we are at detecting it. This probability effect has been studied in numerous forms. However, there is no clear account of the mechanisms driving the effect. While attention and decision-making has been implicated, these interpretations largely hinge on the task employed. Instead, probability might have an earlier effect, one that is perceptual in nature. This thesis explores the idea that feature (e.g. orientation, color, etc.) probability shapes perception through selective tuning of the relevant neurons. Particularly, where orientation probability is involved, V1 neurons preferring the likely orientations are selectively sharpened. To test this hypothesis, a mixture of established tasks (Chapter 2) and novel behavioural paradigms (Chapters 3/4) were utilized. An electrophysiological examination specifically aimed at V1 was also carried out (Chapter 5). Neural modelling was then done to link the behaviour to a concrete neural mechanism, which generated predictions that could be evaluated by additional behavioural data (Chapters 6/7). These diverse methods provide converging evidence for the tuning hypothesis of feature probability, and argue for an interdisciplinary approach in cognitive research.
Probabilistic Adaptation and Voluntary Attention
(University of Waterloo, 2019-04-25) Griffin, Sean; Anderson, Britt
The following experiments considered the general phenomenon of behavioural adaptation in response to statistical regularities—which we refer to as probability learning (PL). In particular, these experiments focused on spatial PL and its relationship with spatial attention. Evidence suggests that the set of neural mechanisms responsible for spatial PL might intersect with those which mediate the voluntary expression of spatial attention. Furthermore, inductions of spatial PL are typically successful in the absence of explicit awareness on the behalf of participants. These findings raise the question of whether spatial PL inductions can be used to subtly alter voluntary behaviour by altering attentional biases. If this is the case, spatial PL inductions could have a wide range of applications—for example as tools in skill training and marketing. We investigated a potential cross-task influence of spatial PL on voluntarily expressed patterns of spatial attention. We used a behavioural task based on the Tse Illusion to measure voluntary shifts in spatial attention (Illusion Task; Tse, Caplovitz, & Hsieh, 2006). We used a feature discrimination task (PL Task) derived from Druker and Anderson (2010) to induce spatial PL. Experiments 1, 2, and 3 combined the Illusion Task with the PL Task in a pre-test/post-test design. Experiment 3’s inclusion of eye tracking permitted us to explore mechanistic hypotheses concerning the cross-task translation of behavioural adaptation. All three experiments revealed that condition-specific variation of the PL Task’s spatial probability distribution produced predictable changes in PL Task performance. Experiment 3 supported the utility of eye-tracking as a tool for understanding the processes underlying spatial PL along with the impact of spatial PL on voluntary attention. We found that we could reliably induce spatially-specific changes in involuntary attention. We produced consistent and robust estimates of the impact of such spatial PL on our feature discrimination task—and, found the effect to be largely driven by changes in eye-movement generation and consequently target acquisition. Finally, we discovered that spatial PL did not influence the expression of voluntary attention in a subsequent task.
Probability Antimatching
(University of Waterloo, 2023-07-20) DiBerardino, Peter; Anderson, Britt
We present a conceptual inversion of probability matching called ``probability antimatching.'' Where probability matching describes a decision strategy of stimulus pursuit, probability antimatching describes an analogous decision strategy of stimulus avoidance. We present three behavioural studies where participants played a computer game of hide-and-seek. Participants played hide-and-seek against a simulated computer opponent that selected rooms for hiding/seeking according to a given probability distribution. Seeking trials replicate traditional probability matching. Hiding trials demonstrate probability antimatching. In Study 1, we formally present our methodology of expressing participant seeking and hiding behaviour as a linear combination of Euclidean vectors. Participant seeking strategies, $\vec{s}$, are well-represented by a linear combination of the optimal maximizing strategy, $\vec{x}$, and the probability matching strategy, $\vec{m}$. Participant hiding strategies, $\vec{h}$, are equally well-represented by a linear combination of the optimal minimizing strategy, $\vec{n}$, and the probability antimatching strategy, $\vec{a}$. We define $\vec{a}$ as a vector reflection of $\vec{m}$ over the uniform distribution vector, $\vec{u}$. This operation is denoted $\vec{a} = refl_{\vec{u}}(\vec{m}) = 2\vec{u} - \vec{m}$. In Study 2, we replicate the findings of Study 1 using data collected online. In Study 3, we demonstrate that our conceptualization of probability antimatching extends to probability distributions that have non-unique optimal hiding/seeking strategies and distributions that have invalid reflections (that result in negative probability values). Across our three studies, we find that hiding/seeking strategies are influenced by the number of rooms presented during hide-and-seek, corresponding to the dimensionality of the underlying probability distributions. However, the direction of this effect fails to replicate across our studies.
Updating Local and Global Probability Events During Maze Navigation
(University of Waterloo, 2022-08-29) Chen, Sixuan; Anderson, Britt
Our mental models consist of relational knowledge. We apply this knowledge about whether something is near to or far from something else to solve tasks. As a specific exam- ple, when we navigate in our environment, we have global (far) location goals that we could navigate to using local (near) landmarks. The question for the present study is whether relational knowledge can be probabilistically and differently represented at global and local levels. To test this, we had participants navigate a maze in which the wall structure was hidden, but in which participants were given global and local cues. We manipulated the reliability of the global and local cues across experimental trials and experiments. Our results demonstrated separable effects for global and local cues. Participants made good estimates of global and local cues’ reliability, however, their estimates of global cue re- liability were less accurate than their estimates of local ones potentially due to inherent differences in how global and local information is represented. Their use of local cues roughly matched the ground truth local cues reliability whereas their use of global cues did not match the ground truth global cue reliability. In addition, participants relied on both local and global cues when they navigated in the mazes but with local cues dominant possibly because of their confidence in local cue reliability estimates, preference for cues associated with more immediate reward, and feedback proximity. Altogether, this study characterizes the mental representations of uncertain global and local cues and suggests that people negotiate between different probabilistic information when making decisions in maze navigation.

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Browsing Psychology by Author "Anderson, Britt"