Perception

Learning to effectively execute goal-directed tasks generally requires guidance from knowledgeable experts that can direct the performer’s attention toward important environmental features. However, specifying the optimal attentional strategies is difficult due to the subjective nature of perceptions and the complexity of the underlying neural processes. The current skill acquisition literature emphasizes action-based contingencies through Predictive and Ecological models when examining attentional processes, while Perceptual Control Theory advocates for perceptual-based mechanisms. To evaluate the efficacy of these models, this study implicitly primed one hundred fifteen participants to focus on action-based or perceptual-based aspects during an interceptive task. It was predicted that the perceptual-based priming condition would result in faster learning and greater resilience to environmental disturbances. However, the highly variable results did not show significant differences in learning rate or resilience between the action and perceptual-based conditions. Ultimately, the variability in the findings suggests that a superior performance depends on numerous factors unique to each performer. Consequently, instructional methods cannot rely on a single optimal attentional strategy for gathering environmental information. Instead, the dynamic interplay between the individual and the environment must be considered to foster the skill development of novice performers.

We examined how adult attachment styles influence human perception of support provision. We invited 119 couples to the lab, where they performed an exploration task. We also used pre- and post-exploration measures, including assessing adult attachment styles and partners' perception of support provided during the task. Three independent coders watched the videos of couples interacting and rated partners' support provision behavior. We utilized West and Kenny's (2011) truth and bias model to compare judgments (partners' perception of support received during the exploration task) with so-defined truth (combined rankings from coders). We used regression analysis to investigate how attachment orientation moderates the perception of support provision. On average, individuals tended to over-perceive helpfulness and under-perceive intrusiveness. Attachment avoidance was not a significant predictor of directional bias for helpfulness and intrusiveness. Results for the second exploratory hypothesis show those higher on attachment anxiety to have a weaker bias in underperceiving intrusiveness.

The main goal of video coding algorithms is to achieve high compression efficiency while
maintaining quality of the compressed signal at the highest level. Human visual system is
the ultimate receiver of compressed signal and final judge of its quality. This dissertation
presents work towards optimal video compression algorithm that is based on the
characteristics of our visual system. Modeling phenomena such as backward temporal
masking and motion masking we developed algorithms that are implemented in the state-of-
the-art video encoders. Result of using our algorithms is visually lossless compression
with improved efficiency, as verified by standard subjective quality and psychophysical
tests. Savings in bitrate compared to the High Efficiency Video Coding / H.265 reference
implementation are up to 45%.

Previous research has shown that priming of digits is a
function of the ordinal distance of the target digit from
the priming sequence and that under certain conditions this
effect may be automatic. The present experiment, which
employs a choice RT task, was designed to test automaticity
by manipulating subjects' expectancies and the time
available for processing the priming sequence.
Schematically valid primes (e.g., "1,2,3" preceding "4")
were presented on 30%, 50%, or 70% of the trials to a given
subject. Invalid primes (e.g., "5, 6, 7" preceding "4")
were presented on the remaining trials. There was a highly
significant effect of priming modified by interactions with
exposure time and frequency. Employing a cost-benefit
analysis to the frequency factor, it was found that the most
frequently occurring prime resulted in decreased response
latency but the less frequently occurring prime did not
result in an increase in response latency (benefit wihout
cost). On this basis, it is concluded that frequency
influences an automatic process in this experiment. Since
frequency interacts with priming, it is therefore argued
that priming also affects an automatic process.

A category effect of alphanumeric characters in a visual search paradigm
was examined to see whether the effect could be accounted for
by the number of memory comparisons or by an early stage of perceptual
processing. In Experiments 1 and 2, subjects searched for
targets in either a within-category or between-category condition.
The two experiments differed by the point in the trials where "catch
trials" were presented. Experiment 3 used new configurations based
on Gestalt principles which had been shown to influence target detection
times at an early level of perceptual processing. The results
of Experiments 1 and 2 favored a perceptual explanation mediating the
effect. In Experiment 3, the critical interaction of category and
Gestalt factors which would have demonstrated a competition in
perceptually parsing the display fell short of significance.

Can a distributed anatomical and functional architecture serve as the basis for sufficiently complex perceptual phenomena? In addressing this question, the conceptual notion of dynamical system and its relation to other paradigms is considered including its definition. The principal goal is to develop a dynamical framework on which to ground the theoretical study of perception and other physical phenomena. As an entry point, the perceptual dynamics of auditory streaming are modeled using a neurally inspired dynamical model of auditory processing. Traditional approaches view streaming as a competition of streams, realized within a tonotopically organized neural network. In contrast, streaming can be viewed as a dynamic integration process involving locations (information convergence zones) other than the sensory specific neural subsystems. This process finds its realization in the synchronization of neural ensembles. Consequently, the model employs two interacting dynamical systems. The first system responds to incoming acoustic stimuli and transforms them into a spatiotemporal neural field dynamics. The second system is a classification system coupled to the neural field and evolves to a stationary state in the absence of input. The states of the classification system at any time t are identified with a single perceptual stream or multiple streams. Several results in human perception are modeled including temporal coherence and fission boundaries (van Noorden, 1975), and crossing of motions (Bregman, 1990). The model predicts phenomena such as the existence of two streams with the same pitch. So far, this has not been explained by the traditional stream competition models. A psychophysical study provides proof of existence of this phenomenon. Using set theoretical expressions on fMRI data, evidence was found showing that the percept of auditory streaming involves regions (convergence zones) other than just the primary auditory areas. This is a necessary condition for the existence of the network architecture proposed in the auditory streaming model. Networks specific and common to both amplitude and frequency streaming were identified. This lends support to models of perception conceived as interacting neural subnetworks acting as functional differentiation areas and information convergence zones for the classification of the perceptual world as suggested by the introductory question.