A meta-analysis of functional magnetic resonance imaging studies of divergent thinking using activation likelihood estimation.

There are conflicting findings regarding brain regions and networks underpinning creativity, with divergent thinking tasks commonly used to study this. A handful of meta-analyses have attempted to synthesise findings on neural mechanisms of divergent thinking. With the rapid proliferation of research and recent developments in fMRI meta-analysis approaches, it is timely to reassess the regions activated during divergent thinking creativity tasks. Of particular interest is examining the evidence regarding large-scale brain networks proposed to be key in divergent thinking and extending this work to consider the role of the semantic control network. Studies utilising fMRI with healthy participants completing divergent thinking tasks were systematically identified, with 20 studies meeting the criteria. Activation Likelihood Estimation was then used to integrate the neuroimaging results across studies. This revealed four clusters: the left inferior parietal lobe; the left inferior frontal and precentral gyrus; the superior and medial frontal gyrus and the right cerebellum. These regions are key in the semantic network, important for flexible retrieval of stored knowledge, highlighting the role of this network in divergent thinking.

A systematic investigation of conceptual color associations.

Associations with colors are a rich source of meaning, and there has been considerable interest in understanding the capacity of color to shape our functioning and behavior as a result of color associations. However, abstract conceptual color associations have not been comprehensively investigated, and many of the effects of color on psychological functioning reported in the literature are therefore reliant on ad hoc rationalizations of conceptual associations with color (e.g., blue = openness) to explain effects. In the present work we conduct a systematic, cross-cultural, mapping of conceptual color associations using the full set of hues from the World Color Survey (WCS). In Experiments 1a and 1b we explored the conceptual associations that English monolingual, Chinese bilingual, and Chinese monolingual speaking adults have with each of the 11 Basic English Color Terms (black, white, red, yellow, green, blue, brown, purple, pink, orange, gray). In Experiment 2 we determined which specific physical WCS colors are associated with which concepts in these three language groups. The findings reveal conceptual color associations that appear to be universal across all cultures (e.g., white - purity; blue - water/skyrelated; green - health; purple - regal; pink - "female" traits) as well as culture specific (e.g., red and orange - enthusiastic in Chinese; red - attraction in English). Importantly, the findings provide a crucial constraint on, and resource for, future work that seeks to understand the effect of color on cognition and behavior, enabling stronger a priori predictions about universal as well as culturally relative effects of conceptual color associations on cognition and behavior to be systematically tested. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Chromatic Perceptual Learning but No Category Effects without Linguistic Input.

Perceptual learning involves an improvement in perceptual judgment with practice, which is often specific to stimulus or task factors. Perceptual learning has been shown on a range of visual tasks but very little research has explored chromatic perceptual learning. Here, we use two low level perceptual threshold tasks and a supra-threshold target detection task to assess chromatic perceptual learning and category effects. Experiment 1 investigates whether chromatic thresholds reduce as a result of training and at what level of analysis learning effects occur. Experiment 2 explores the effect of category training on chromatic thresholds, whether training of this nature is category specific and whether it can induce categorical responding. Experiment 3 investigates the effect of category training on a higher level, lateralized target detection task, previously found to be sensitive to category effects. The findings indicate that performance on a perceptual threshold task improves following training but improvements do not transfer across retinal location or hue. Therefore, chromatic perceptual learning is category specific and can occur at relatively early stages of visual analysis. Additionally, category training does not induce category effects on a low level perceptual threshold task, as indicated by comparable discrimination thresholds at the newly learned hue boundary and adjacent test points. However, category training does induce emerging category effects on a supra-threshold target detection task. Whilst chromatic perceptual learning is possible, learnt category effects appear to be a product of left hemisphere processing, and may require the input of higher level linguistic coding processes in order to manifest.

Modeling learned categorical perception in human vision.

A long standing debate in cognitive neuroscience has been the extent to which perceptual processing is influenced by prior knowledge and experience with a task. A converging body of evidence now supports the view that a task does influence perceptual processing, leaving us with the challenge of understanding the locus of, and mechanisms underpinning, these influences. An exemplar of this influence is learned categorical perception (CP), in which there is superior perceptual discrimination of stimuli that are placed in different categories. Psychophysical experiments on humans have attempted to determine whether early cortical stages of visual analysis change as a result of learning a categorization task. However, while some results indicate that changes in visual analysis occur, the extent to which earlier stages of processing are changed is still unclear. To explore this issue, we develop a biologically motivated neural model of hierarchical vision processes consisting of a number of interconnected modules representing key stages of visual analysis, with each module learning to exhibit desired local properties through competition. With this system level model, we evaluate whether a CP effect can be generated with task influence to only the later stages of visual analysis. Our model demonstrates that task learning in just the later stages is sufficient for the model to exhibit the CP effect, demonstrating the existence of a mechanism that requires only a high-level of task influence. However, the effect generalizes more widely than is found with human participants, suggesting that changes to earlier stages of analysis may also be involved in the human CP effect, even if these are not fundamental to the development of CP. The model prompts a hybrid account of task-based influences on perception that involves both modifications to the use of the outputs from early perceptual analysis along with the possibility of changes to the nature of that early analysis itself.

Tactile elevation perception in blind and sighted participants and its implications for tactile map creation.

OBJECTIVE: Our goal was to determine the optimal elevation of tactile map symbols. BACKGROUND: Tactile perception research predicts that symbol elevation (vertical height) and texture on tactile maps could influence their readability. However, although research has shown that elevation influences detection and discrimination thresholds for single tactile stimuli and that the physiological response of fingertip receptors varies with texture, little is known about the influence of these parameters on the identification of stimuli in the context of multiple symbols as found on tactile maps. METHOD: Sighted and visually impaired participants performed tactile symbol identification tasks. In Experiment 1, we measured the effect of elevation on identification accuracy. In Experiment 2, we measured the effect of elevation and symbol texture on identification speed. RESULTS: Symbol elevation influenced both speed and accuracy of identification; thresholds were higher than those found in work on detection and discrimination but lower than on existing tactile maps. Furthermore, as predicted from existing knowledge of tactile perception, rough features were identified more quickly than smooth ones. Finally, visually impaired participants performed better than sighted ones. CONCLUSION: The symbol elevations necessary for identification (0.040 to 0.080 mm) are considerably lower than would be expected on the basis of existing tactile maps (generally 0.5 mm or higher) and design guidelines (0.4 mm). APPLICATION: Tactile map production costs could be reduced and map durability increased by reducing symbol elevation. Furthermore, legibility of maps could be improved by using rough features, which are read more easily, and smaller symbols, which reduce crowding of graphics.

Your hand or mine? The extrastriate body area.

Visual images of our own and others' body parts can be highly similar, but the types of information we wish to extract from them are highly distinct. From our own body we wish to combine visual information with, at least, somatosensory, proprioceptive and motor information in order to guide our interpretation of sensory events and our actions upon the world. For others' bodies we only have visual information available, but from that we can derive much useful social information including their age, health, gender, emotional state and intentions. Consequently, a challenge for the brain is to sort visual images of our own bodies, to be integrated with processing from other sensory modalities, from highly similar images of others' bodies for social cognition. We explored the possibility that the extrastriate body area (EBA) may help to accomplish this sorting. Previous work had suggested that the EBA is responsive to images of both our own and others' body parts but does not distinguish between them. Here, using fMRI adaptation, we provide evidence that the right EBA contains separate neural sub-populations that are selectively sensitive to images of our own or others' body parts. Thus, we argue that the right EBA may perform an important sorting of body part images by identity (including self-recognition) and may interact both with brain areas involved in sensory processing and social cognition having identified our own and others' body part images respectively.

Channel surfing in the visual brain.

Vision provides us with an ever-changing neural representation of the world from which we must extract stable object categorizations. We argue that visual analysis involves a fundamental interaction between the observer's top-down categorization goals and the incoming stimulation. Specifically, we discuss the information available for categorization from an analysis of different spatial scales by a bank of flexible, interacting spatial-frequency (SF) channels. We contend that the activity of these channels is not determined simply bottom-up by the stimulus. Instead, we argue that, following perceptual learning a specification of the diagnostic, object-based, SF information dynamically influences the top-down processing of retina-based SF information by these channels. Our analysis of SF processing provides a case study that emphasizes the continuity between higher-level cognition and lower-level perception.

Retinotopic sensitisation to spatial scale: evidence for flexible spatial frequency processing in scene perception.

Observers can use spatial scale information flexibly depending on categorisation task and on their prior sensitisation. Here, we explore whether attentional modulation of spatial frequency processing at early stages of visual analysis may be responsible. In three experiments, we find that observers' perception of spatial frequency (SF) band-limited scene stimuli is determined by the SF content of images previously experienced at that location during a sensitisation phase. We conclude that these findings are consistent with the involvement of relatively early, retinotopically mapped, stages of visual analysis, supporting the attentional modulation of spatial frequency channels account of sensitisation effects.

The nature of learned categorical perception effects: a psychophysical approach.

Categorical perception is often cited as a striking example of cognitive influences on perception. However, some evidence suggests the term is a misnomer, with effects based on cognitive not perceptual processing. Here, using a psychophysical approach, we provide evidence consistent with a learned categorical perception effect that is dependent on analysis within the visual processing stream. An improvement in participants' discrimination between grating patterns that they had learned to place in different categories was 'tuned' around the orientation of the patterns experienced during category learning. Thus, here, categorical perception may result from attentionally modulated perceptual learning about diagnostic category features, based upon orientation-selective stages of analysis. This argues strongly that category learning can alter our perception of the world.

Expectancy effects on spatial frequency processing.

We explored top-down modulation of spatial frequency (SF) processing. When auditory pre-cueing directed observers' attention to one of two 4-octaves (SF) apart plaid components observers tended to perceive the cued component, suggesting selective attention to the SF channel they expected to carry task relevant information. In agreement, pre-cueing had no effect with components often processed by the same channel (0.5-octaves apart). Further, effects of expectancy were greater than of uncertainty and were SF tuned. Combined our findings suggest top-down modulation of early, cortical, SF processing. We argue this could similarly explain the previously reported influences of categorisation on SF processing.

Perceptual learning of luminance contrast detection: specific for spatial frequency and retinal location but not orientation.

Performance of a wide range of simple visual tasks improves with practice. Here we ask whether such learning occurs for the fundamental visual task of luminance contrast detection. In two experiments we find that contrast sensitivity increases following extensive practice at detecting briefly presented sinusoidal luminance gratings and that learning is maintained after six months. Learning is spatial frequency tuned, specific to retinal location and can be specific to one eye, but is not selective for orientation. The selectivity of learning implies that it is based on plasticity in early visual, as opposed to central cognitive, processing mechanisms.