The physicality of representation

Representation is typically taken to be importantly separate from its physical implementation. This is exemplified in Marr's three-level framework, widely cited and often adopted in neuroscience. However, the separation between representation and physical implementation is not a necessary feature of information-processing systems. In particular, when it comes to analog computational systems, Marr's representational/algorithmic level and implementational level collapse into a single level. Insofar as analog computation is a better way of understanding neural computation than other notions, Marr's three-level framework must then be amended into a two-level framework. However, far from being a problem or limitation, this sheds lights on how to understand physical media as being representational, but without a separate, medium-independent representational level.

Effects of pointing movements on visuospatial working memory in a joint-action condition: Evidence from eye movements

Previous studies showed that (a) performing pointing movements towards to-be-remembered locations enhanced their later recognition, and (b) in a joint-action condition, experimenter-performed pointing movements benefited memory to the same extent as self-performed movements. The present study replicated these findings and additionally recorded participants’ fixations towards studied arrays. Each trial involved the presentation of two consecutive spatial arrays, where each item occupied a different spatial location. The item locations of one array were encoded by mere visual observation (the no-move array), whereas the locations of the other array were encoded by observation plus pointing movements (the move array). Critically, in Experiment 1, participants took turns with the experimenter in pointing towards the move arrays (joint-action condition), while in Experiment 2 pointing was performed only by the experimenter (passive condition). The results showed that the locations of move arrays were recognized better than the locations of no-move arrays in Experiment 1, but not in Experiment 2. The pattern of eye-fixations was in line with behavioral findings, indicating that in Experiment 1, fixations to the locations of move arrays were higher in number and longer in duration than fixations to the locations of no-move arrays, irrespective of the agent who performed the movements. In contrast, no differences emerged in Experiment 2. We propose that, in the joint-action condition, self- and other-performed pointing movements are coded at the same representational level and their functional equivalency is reflected in a similar pattern of eye-fixations.

Distinct progressions of neuronal activity changes underlie the formation and consolidation of a gustatory associative memory

Acquiring new memories is a multi-stage process. Ample of studies have convincingly demonstrated that initially acquired memories are labile, and only stabilized by later consolidation processes. These multiple phases of memory formation are known to involve modification of both cellular excitability and synaptic connectivity, which in turn change neuronal activity at both the single neuron and ensemble levels. However, the specific mapping between the known phases of memory and the observed changes in neuronal activity remains unknown. Here we address this unknown in the context of conditioned taste aversion learning by continuously tracking gustatory cortex (GC) neuronal taste responses from alert rats in the 24 hours following a taste-malaise pairing. We found that the progression of neuronal activity changes in the GC depend on the neuronal organizational level. The population response changed continuously; these changes, however, were only reflected in the population mean amplitude during the acquisition and consolidation phases, and in the known quickening of the ensemble state dynamics after the time of consolidation. Together our results demonstrate how complex dynamics in different representational level of cortical activity underlie the formation and stabilization of memory within the cortex.

Reimagining GIS Instruction through Concept-Based Learning

Research in geographic information science has not yet found clear answers to the questions of what geographic information is about or what a geographic information system (GIS) contains. This lack of consensus makes it especially challenging to teach and learn GIS. Existing pedagogical approaches either focus on the representational level of data (e.g., “raster and vector”) or are too generic (e.g., “geo-referenced information”). This characterization of GIS and its content is difficult for learners to transfer and apply broadly. As instructors, we approach the challenge of teaching GIS from a conceptual basis. We describe our process to develop a set of core concepts of spatial information, which we use to redesign an undergraduate-level introductory GIS course. Our intervention focuses instruction on the kinds of questions that geographic information enables before training students to produce workflows and answers through system commands. The course redesign complements and informs ongoing research on core concepts of spatial information. Our results demonstrate that GIS courses can deliver more than software training, indicating both theoretical gains and didactic challenges.

Sparse deep predictive coding captures contour integration capabilities of the early visual system

Both neurophysiological and psychophysical experiments have pointed out the crucial role of recurrent and feedback connections to process context-dependent information in the early visual cortex. While numerous models have accounted for feedback effects at either neural or representational level, none of them were able to bind those two levels of analysis. Is it possible to describe feedback effects at both levels using the same model? We answer this question by combining Predictive Coding (PC) and Sparse Coding (SC) into a hierarchical and convolutional framework applied to realistic problems. In the Sparse Deep Predictive Coding (SDPC) model, the SC component models the internal recurrent processing within each layer, and the PC component describes the interactions between layers using feedforward and feedback connections. Here, we train a 2-layered SDPC on two different databases of images, and we interpret it as a model of the early visual system (V1 & V2). We first demonstrate that once the training has converged, SDPC exhibits oriented and localized receptive fields in V1 and more complex features in V2. Second, we analyze the effects of feedback on the neural organization beyond the classical receptive field of V1 neurons using interaction maps. These maps are similar to association fields and reflect the Gestalt principle of good continuation. We demonstrate that feedback signals reorganize interaction maps and modulate neural activity to promote contour integration. Third, we demonstrate at the representational level that the SDPC feedback connections are able to overcome noise in input images. Therefore, the SDPC captures the association field principle at the neural level which results in a better reconstruction of blurred images at the representational level.

Visualizing chemistry teachers’ enacted assessment design practices to better understand barriers to “best practices”

Even when chemistry teachers’ beliefs about assessment design align with literature-cited best practices, barriers can prevent teachers from enacting those beliefs when developing day-to-day assessments. In this paper, the relationship between high school chemistry teachers’ self-generated “best practices” for developing formative assessments and the assessments they implement in their courses are examined. Results from a detailed evaluation of several high school chemistry formative assessments, learning goals, and learning activities reveal that assessment items are often developed to require well-articulated tasks but lack either alignment regarding representational level or employ only one representational level for nearly all assessment items. Implications for the development of a chemistry-specific method for evaluating alignment are presented as well as implications for high school chemistry assessment design.

Lying and Deception in Development

Human self-consciousness and symbolic functioning bring deception to new levels, incomparable to all the other forms of deception found in other animals or in nature in general. It brings intention and open-ended delusional redescription of reality to fit our social needs, boost our self-worth, and maintain semblance of self-unity. Children learn and develop quickly the ability to use semblances as the primary tool in their navigation of the social world, gaining affiliation through the debunking and deliberate creation of false or pseudo beliefs. In fact, the catalogue of lies and deception found in toddlers starting at two years, even if they are at basic, putatively nonstrictly representational level (i.e., without explicit false belief understanding) is stunning.

Tablet Assessment of Word Comprehension Reveals Coarse Word Representations in 18-20-month-old Toddlers

The present study explores the viability of using tablets in assessing early word comprehension by means of a two-alternative forced-choice task. Forty-nine 18-20-month-old Norwegian toddlers performed a touch-based word recognition task, in which they were prompted to identify the labelled target out of two displayed items on a touchscreen tablet. In each trial, the distractor item was either semantically related (e.g., dog-cat) or unrelated (e.g., dog-airplane) to the target. Our results show that toddlers as young as 18 months can engage meaningfully with a tablet-based assessment, with minimal verbal instruction and child–administrator interaction. Toddlers performed better in the semantically unrelated condition than in the related condition, suggesting that their word representations are still semantically coarse at this age. Furthermore, parental reports of comprehension, using the Norwegian version of the MacArthur Bates Communicative Development Inventories, predicted toddlers’ performance, with parent-child agreement stronger in the semantically unrelated condition, suggesting that parents declare a word to be known by their child if it is understood at a coarse representational level. This study provides among the earliest evidence that remote data collection in infants before their second birthday is viable, as comparable results were observed from both in-lab and online administration of the touch-screen recognition task.

Phonologic representation and speech perception: The role of pause

We investigate the perception of pauses at intonational phrase (IP) boundaries in Brazilian Portuguese (BP) and addresses the discussion about the relation between speech production and perception. Twenty adult subjects, native speakers of BP, with no language disorders and no hearing complaints, took part in an experimental pause identification test. We used auditory stimuli in which the IP-boundary was marked by a combination of pause and pitch variation or pitch variation only. The results are the following: (i) when stimuli consisted of a combination of pause with pitch variation in the IP-boundary, pauses were identified significantly (ii) when the stimuli did not have pitch variation on IP-boundaries, pauses were not identified significantly, (iii) when only pitch variation occurred, without pause production, pauses were identified in the tested boundary. These results support the argument that speech perception does not depend entirely on recovering an acoustic pattern and provide evidence for the importance of phonologic representation for the perception and organization of the perceived auditory stimulus. Based on the results, we argue that pause perception would result from the perceptual illusion marked by the combination of different types of linguistic information, at a phonetic-acoustic and representational level.

Accounting for graded structure in adjective categories with valence-based opposition relationships

In contrast to noun categories, little is known about the graded structure of adjective categories. In this study, we investigated whether adjective categories show a similar graded structure and what determines this structure. The results show that adjective categories like nouns exhibit a reliable graded structure. Similar to nouns, we investigated whether similarity is the main determinant of the graded structure. We derived a low-dimensional similarity representation for adjective categories and found that valence differences in adjectives constitute an important organising principle in this similarity space. Valence was not implicated in the categories' graded structure, however. A formal similarity-based model using exemplars accounted for the graded structure by effectively discarding the valence differences between adjectives in the similarity representation through dimensional weighting. Our results generalise similarity-based accounts of graded structure and highlight a closely knit relationship between adjectives and nouns on a representational level.