Marcus R Watson

York University · Department of Biology

Learning and synesthesia are profoundly interconnected. On the one hand, the development of synesthesia is clearly influenced by learning. Synesthetic inducers – the stimuli that evoke these unusual experiences – often involve the perception of complex properties learned in early childhood, e.g., letters, musical notes, numbers, months of the year,...

Visual search can be made more efficient by adopting a passive cognitive strategy (i.e., letting the target "pop" into mind) rather than by trying to actively guide attention. In the present study, we examined how this strategic benefit is linked to eye movements. Results show that participants using a passive strategy wait longer before beginning...

Typically, the search for order in grapheme-color synesthesia has been conducted by looking at the frequency of certain letter-color associations. Here, we report stronger associations when second-order similarity mappings are examined--specifically, mappings between the synesthetic colors of letters and letter shape, frequency, and position in the...

Learning to identify objects as members of categories is an essential cognitive skill and learning to deploy attention effectively is a core component of that process. The present study investigated an assumption imbedded in formal models of categorization: error is necessary for attentional learning. Eye-trackers were used to record participants’...

Background: Understanding the neurobiological substrates of psychiatric disorders requires comprehensive evaluations of cognitive and motivational functions in preclinical research settings. The translational validity of such evaluations will be supported by (1) tasks with high construct validity that are engaging and easy to teach to human and non...

Prospective gains and losses influence cognitive processing, but it is unresolved how they modulate flexible learning in changing environments. The prospect of gains might enhance flexible learning through prioritized processing of reward-predicting stimuli, but it is unclear how far this learning benefit extends when task demands increase. Similar...

Flexible learning of changing reward contingencies can be realized with different strategies. A fast learning strategy involves using working memory of recently rewarded objects to guide choices. A slower learning strategy uses prediction errors to gradually update value expectations to improve choices. How the fast and slow strategies work togethe...

Nonhuman primates (NHP’s) are self-motivated to perform cognitive tasks on touchscreens in their animal housing setting. To leverage this ability, fully integrated hardware and software solutions are needed that work within housing and husbandry routines while also spanning cognitive task constructs of the Research Domain Criteria (RDoC). Here, we...

The Campbell-Robson chart is a highly popular figure used in psychophysics and visual perception textbooks to illustrate the Contrast Sensitivity Function (CSF). The chart depicts a grating which varies logarithmically in spatial frequency (SF) from left to right and in contrast from bottom to top. Campbell and Robson’s (1964) intuition was that th...

Background: Nonhuman primates (NHPs) are self-motivated to perform cognitive tasks on touchscreens in their animal housing setting. To leverage this ability, fully integrated hardware and software solutions are needed, that work within housing and husbandry routines while also spanning cognitive task constructs of the Research Domain Criteria (RDoC...

Flexible learning of changing reward contingencies can be realized with different strategies. A fast learning strategy involves using working memory of recently rewarded objects to guide choices. A slower learning strategy uses prediction errors to gradually update value expectations to improve choices. How the fast and slow strategies work togethe...

Prospective gains and losses modulate cognitive processing, but it is unresolved whether gains and losses can facilitate flexible learning in changing environments. The prospect of gains might enhance flexible learning through prioritized processing of reward-predicting stimuli but is unclear how far this learning benefit extends when task demands...

Saccade detection is a critical step in the analysis of gaze data. A common method for saccade detection is to use a simple threshold for velocity or acceleration values, which can be estimated from the data using the mean and standard deviation. However, this method has the downside of being influenced by the very signal it is trying to detect, th...

Significance The perceptual validity of synesthesia has been established by behavioral and neuroimaging evidence; however, its developmental origins remain unclear. Here we tested the hypothesis that synesthesia arises when there is less experience-dependent pruning during development. We did so by comparing adults with and without synesthesia on a...

Saccade detection is a critical step in the analysis of gaze data. A common method for saccade detection is to use a simple threshold for velocity or acceleration values, which is typically estimated from the data using the mean and standard deviation. However, this method has the downside of being influenced by the very signal it is trying to dete...

Background: There is a growing interest in complex, active, and immersive behavioral neuroscience tasks. However, the development and control of such tasks present unique challenges. New method: The Unified Suite for Experiments (USE) is an integrated set of hardware and software tools for the design and control of behavioral neuroscience experi...

1.1 Background There is a growing interest in complex, active, and immersive behavioral neuroscience tasks. However, the development and control of such tasks present unique challenges. 1.2 New Method The Unified Suite for Experiments ( USE ) is an integrated set of hardware and software tools for the design and control of behavioral neuroscience...

Many studies of vision and cognition require novel three-dimensional object sets defined by a parametric feature space. Creating such sets and verifying that they are suitable for a given task, however, can be time-consuming and effortful. Here we present a new set of multidimensional objects, Quaddles, designed for studies of feature-based learnin...

Depth perception is the ability of humans and other sighted animals to see objects as having volume (as opposed to seeing flat silhouettes) and to see the relative position of objects in a three-dimensional environment (as opposed to in a twodimensional picture). This ability is crucial for everyday action. Pushing an elevator button requires infor...

Previously learned reward values can have a pronounced impact, behaviorally and neurophysiologically, on the allocation of selective attention. All else constant, stimuli previously associated with a high value gain stronger attentional prioritization than stimuli previously associated with a low value. The N2pc, an ERP component indicative of atte...

Many studies of vision and cognition require novel three-dimensional object sets defined by a parametric feature space. Creating such sets and verifying that they are suitable for a given task, however, can be extremely time-consuming and effortful. Here we present a new set of multidimensional objects, Quaddles , designed for a study of feature-ba...

This call to revolution in theories of visual search does not go far enough. Treating fixations as uniform is an oversimplification that obscures the critical role of the mind. We remind readers that what happens during a fixation depends on mindset, as shown in studies of search strategy and of humans' ability to rapidly resume search following an...

Inspired by Vicker's (2016) comprehensive review of the quiet eye (QE) in athletics, we review two sets of findings from laboratory studies of typical university students performing visual search tasks. These studies also point to a relationship between longer fixation durations and improved performance , in keeping with the QE in elite athletes. T...

Patients with the autosomal recessive disorder phenylketonuria (PKU) have elevated phenylalanine levels that impede production of tyrosine, a precursor to dopamine. Lowered dopamine levels lead to a number of deficits, including lowered visual contrast sensitivity (Diamond & Herzberg, 1996; Gramer et al, 2013; Stemerdink et al, 1999). In the presen...

Synaesthesia is a neurological condition in which input to one sense causes an automatic and consistent extra percept, often in another sense (e.g., C sharp elicits a pale yellow). Synaesthesia is hypothesized to arise, at least in part, from less-than-normal neural pruning of the exuberant connections in sensory cortical areas during infancy (revi...

Many theories of category learning incorporate mechanisms for selective attention, typically implemented as attention weights that change on a trial-by-trial basis. This is because there is relatively little data on within-trial changes in attention. We used eye tracking and mouse tracking as fine-grained measures of attention in three complex visu...

Depth perception is the ability to see the three-dimensional volume of objects and the spatial layout of objects relative to one another and the viewer. Humans accomplish depth perception using a variety of cues, including some based on how the eyes and brain function in concert and others that rely on lawful regularities in the environment. The to...

Does person perception--the impressions we form from watching others--hold clues to the mental states of people engaged in cognitive tasks? We investigated this with a two-phase method: In Phase 1, participants searched on a computer screen (Experiment 1) or in an office (Experiment 2); in Phase 2, other participants rated the searchers' video-reco...

Humans have an extremely flexible ability to categorize regularities in their environment, in part because of attentional systems that allow them to focus on important perceptual information. In formal theories of categorization, attention is typically modeled with weights that selectively bias the processing of stimulus features. These theories ma...

We used an eye-tracker to investigate the allocation of overt attention during feedback on a categorization task. Results suggest several conclusions: (1) Participants spend a significant amount of time attending to stimuli re-presented during feedback, indicating that this re-presentation may play an important role in learning. (2) Participants sp...