Object attention sharpens the tuning of the perceptual template and interacts with task precision

Perceptual learning (PL) can significantly improve human performance in perceptual tasks primarily through template reweighting. Previous studies have documented how PL changes perceptual template in stimulus feature space. We investigated how PL reweights visual information in time. With a dynamic external noise paradigm and the elaborated perceptual template model (ePTM) analysis, we found that training with an orientation identification task in the zero external noise condition reduced contrast thresholds in both zero and high external noise conditions, whereas training in the high external noise condition only reduced contrast thresholds in high external noise conditions. The ePTM analysis showed that training in both zero and high external noise changed the overall amplitude, but not the shape of the temporal window of the perceptual template to exclude external noise across time, and training in zero external noise additionally reduced additive internal noise. Our results provided additional constraints for models of PL. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

The improvements due to small incision lenticule extraction (SMILE) in vision, e.g., in spherical equivalent (SE) and visual acuity (VA), has been widely recognized. However, the contrast sensitivity (CS) change after SMILE was not certain. Here, we investigated the effect of SMILE on CS before, 1 day after and 7 days after surgery and then clarified the corresponding mechanism by using a perceptual template model (PTM). In addition, the relationship among SE, VA, and CS was discussed. The quick contrast sensitivity function (qCSF) was applied to measure CS with high precision and accuracy. We found that (1) CS was significantly improved 1 day after SMILE and was also increased 7 days after the surgery, (2) CS improvements were dependent on spatial frequency and external noise, (3) the increase in CS was due to the decreased internal additive noise and an enhanced perceptual template, and (4) Greater SE improvements predicted better VA improvements 1 day after SMILE, and a positive correlation between SE improvements and AULCSF improvements 7 days after SMILE was observed. These findings help us better understand the effect of SMILE and provide effective indicators for future visual research.

The external noise paradigm and perceptual template model (PTM) have successfully been applied to characterize observer properties and mechanisms of observer state changes (e.g. attention and perceptual learning) in several research domains, focusing on individual level analysis. In this study, we developed a new hierarchical Bayesian perceptual template model (HBPTM) to model the trial-by-trial data from all individuals and conditions in a published spatial cuing study within a single structure and compared its performance to that of a Bayesian Inference Procedure (BIP), which separately infers the posterior distributions of the model parameters for each individual subject without the hierarchical structure. The HBPTM allowed us to compute the joint posterior distribution of the hyperparameters and parameters at the population, observer, and experiment levels and make statistical inferences at all these levels. In addition, we ran a large simulation study that varied the number of observers and number of trials in each condition and demonstrated the advantage of the HBPTM over the BIP across all the simulated datasets. Although it is developed in the context of spatial attention, the HBPTM and its extensions can be used to model data from the external noise paradigm in other domains and enable predictions of human performance at both the population and individual levels.

The discrimination of two stimuli can be measured as a contrast threshold at a constant stimulus difference (i.e., +/− 45 deg orientation) or as an orientation threshold at a given contrast. Both can be understood together within an elaborated perceptual template model (ePTM) that incorporates the effects of judgment precision, or non-orthogonal stimuli for discrimination (Jeon, Lu, & Dosher, 2008). Perceptual learning improvements in contrast thresholds have been studied in different external noise conditions (Dosher & Lu, 1998, 1999), while stimulus difference thresholds have not. Here we investigate orientation psychometric functions and thresholds and perceptual learning. (1) Orientation thresholds in zero noise and in high noise improve with practice in a peripheral orientation discrimination experiment in which the angles of discrimination are altered by an adaptive staircase; threshold angle difference narrowed gradually with practice. (2) Orientation psychometric functions were measured at three contrast levels and eight external noise levels to measure orientation threshold TvC functions at fovea; consistent with prior reports (Lu & Dosher, 2004) foveal performance showed little or no effect of learning comparing the first to the last half of sessions. (3) A similar experiment measured orientation discrimination at 5 deg in the periphery; peripheral discrimination performance showed perceptual learning between the first and last half of sessions, with larger learning effects in high external noise. In both (2) and (3) the ePTM provided a very good account of the orientation psychometric functions in different levels of external noise. These results widely validate the elaborated perceptual template model in accounting for accuracy as a joint function of orientation difference, contrast, and external noise, with perceptual learning resulting in reduced impact of external and additive internal noises.

We investigated the mechanisms by which perceptual learning improves performance with practice using high- and low-pass filtered external noise. Observers were trained in a 4AFC orientation identification task with Gabor stimuli embedded in external noise at two spatial locations. The spatial frequency characteristics of external noise were systematically manipulated through high-pass and low-pass filtering and added to the signal stimulus. Contrast thresholds were measured as a function of the cutoff spatial frequency of the high-pass and low-pass filters and practice. Adaptive staircases adjusted contrasts to track 79.4 and 70.7 percent correct with 1620 trials per session for a total of 18 sessions. Observers identified the orientation of the Gabor in the pre-cued location in each trial. Different spatial frequency conditions and locations were intermixed randomly during training. This is the first study to use filtered external noises during training. Observers showed systematic reductions in contrast thresholds over the course of training. Although the amplitude of the threshold versus cutoff frequency functions decreased, the relationship between the low-pass and high-pass threshold versus cutoff spatial frequency functions remained substantially equivalent through the course of perceptual learning. The performance returned essentially to initial levels after a switch to new retinal locations of testing, indicating specificity of the learning. A perceptual template model elaborated to estimate spatial frequency sensitivity of the template (Lu & Dosher, 2001) was used to account for the threshold versus cutoff functions through the course of training. We found that perceptual learning improved performance in external noise without changing the spatial frequency tuning of external noise sensitivity, in parallel with previous findings in spatially cued attention (Lu & Dosher, 2004). The improved tuning of the perceptual template with practice may occur in orientation rather than spatial frequency tuning. Meeting abstract presented at VSS 2016

Working memory (WM) deficits are a core feature of schizophrenia (SZ) with prognostic significance. Past work indicates that abnormal perceptual encoding plays an important role in WM deficits, but the mechanism of this association is unclear. In this study, we tested the hypothesis that ‘noisy’ perception in SZ cascades to imprecise WM representations by using a human-observer model to estimate internal noise (IN) during visual perception and examining its relation with visual WM precision. Individuals with SZ and demographically-matched healthy controls (HC) completed a perceptual discrimination task to estimate IN levels and an analog visual WM task to examine how IN relates to WM precision. The perceptual discrimination task involved distinguishing orientations of briefly presented gratings (1 cycle/°; tilted ±45° from vertical) embedded in varying levels of external noise (0%–21%). Contrast thresholds were estimated, and IN was modeled from task performance with the perceptual template model. The WM task required reproducing remembered orientations of high-contrast gratings (same size and spatial frequency as in the discrimination task) with a manual dial at a 1s delay. WM precision was computed as the concentration of the von Mises distribution, fit from subjects’ orientation errors. Estimated IN during perceptual discrimination was significantly increased in SZ compared to HC. WM precision was reduced in SZ at every set size. IN was negatively correlated with WM precision for SZ and HC. IN was also negatively correlated with IQ, while WM precision was positively correlated with IQ. We found evidence of elevated IN levels during visual perception in SZ, which were inversely related to their visual WM precision. Results support a model of ‘noisy’ perception in SZ that may underlie broad cognitive impairment. While future work must identify the specific neural drivers of IN level, we posit that it might broadly reflect a functional imbalance of excitatory/inhibitory neurotransmission in related cortical networks. Findings underscore the link between perception and WM encoding in SZ and offer a novel computational strategy for identifying common pathophysiological mechanisms of SZ cognitive dysfunction.

The underlying mechanisms responsible for the improvements in cognition associated with video game play are less understood than the benefits. It is unclear whether cognitive improvements associated with video game play result from play in general (domain-general improvements) or from playing specific types of games (domain-specific improvements). These improvements may be evaluated through comparisons of two cognitive models: the domain-specific, transfer-appropriate processing model (TAPM) and the domain-general, perceptual template model (PTM). TAPM suggests that improvements in cognitive skills occur only when a training task requires their implementation, whereas PTM suggests that cognitive skills may be improved by non-task specific training which may lead to better allocate attentional resources. Performance metrics from selective attention and inhibitory control constructs were compared between participants with general video game experience, genre-specific experience, and no video game experience to determine how prior experience affected performance. The hypotheses related to cognitive improvements associated with video game play were not statistically supported in this study. The researchers concluded that there is a need for improved operationalization of video game experience, methodological approaches to address confounding variables (different game platforms and gaming habits), and development of more sensitive cognitive measures to better assess changes in cognition.