The Time-Course of Visual Categorizations: You Spot the Animal Faster than the Bird

Background: Since the pioneering study by Rosch and colleagues in the 70s, it is commonly agreed that basic level perceptual categories (dog, chair…) are accessed faster than superordinate ones (animal, furniture…). Nevertheless, the speed at which objects presented in natural images can be processed in a rapid go/no-go visual superordinate categorization task has challenged this ‘‘basic level advantage’’. Principal Findings: Using the same task, we compared human processing speed when categorizing natural scenes as containing either an animal (superordinate level), or a specific animal (bird or dog, basic level). Human subjects require an additional 40–65 ms to decide whether an animal is a bird or a dog and most errors are induced by non-target animals. Indeed, processing time is tightly linked with the type of non-targets objects. Without any exemplar of the sam

Salivating for Knowledge: Potential Pharmacological Agents in Tick Saliva

Joppe Hovius and colleagues review anticoagulant and immunosuppressive proteins present in tick saliva, and discuss how immunologically targeting such molecules could prevent transmission of tick-borne pathogens

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Catégorisation rapide des scènes naturelles : L'objet, le contexte, et leurs interactions

In a world governed by physical laws, our brain is able to extract some invariants and to generate expectations to define our visual percept. However, as soon as we turn on the light of a dark room, as soon as we zap to a new tv channel, we understand nearly instantaneously the content of these new complex scenes. How rapidly are we able to extract the gist of natural scenes? Which influence has the context on the recognition of relevant object ? What are the necessary visual information and the underlying visual processing ? The first two papers of this thesis show our capacity to recognize context superordinate categories of natural scenes in less than 400 ms while the access to basic categories needs about 50 ms of additional processing. They reveal also that the presence of salient objects interferes with rapid context categorization. These short processing times that are very similar to those obtained in object categorization tasks suggest a global and parallel processing of the whole scene. The third paper shows that the context congruency with the object immediately influences object categorization processing and the last one analyses the visual information necessary in context processing. Based on such data, I support the idea of early crossed interactions between parallel bottom-up visual processings of object and context. A final study aimed at determining the minimal latency for such interactions by using ocular response rather than manual response. The implications of these fundamental results are discussed in the perspective of future researches.Dans un monde régi par les lois physiques, notre cerveau est capable d'extraire des invariants et de générer des attentes pour préciser notre percept visuel. Pourtant, en éclairant une pièce, ou en naviguant à travers les chaînes de télévision, nous comprenons quasi-instantanément l'essence de ces nouvelles scènes naturelles. A quelle vitesse peut-on extraire une représentation sémantique globale des scènes? Quelle est l'influence du contexte sur la reconnaissance de l'objet d'intérêt? Quelles sont les informations visuelles nécessaires et la nature des traitements sous-jacents? Les deux premiers articles démontrent notre capacité à reconnaître la catégorie superordonnée du contexte d'une scène en moins de 400 ms tandis que l'accès au niveau basique nécessite 50 ms de traitement additionnel. Ils démontrent aussi que la présence d'objets saillants interfère sur la catégorisation rapide du contexte. Ces temps de traitements très similaires à ceux enregistrés dans la catégorisation rapide d'objets suggèrent un traitement global et parallèle de l'ensemble de la scène. Le troisième article montre que la congruence (incongruence) du contexte avec l'objet influence immédiatement le traitement de l'objet et le dernier précise les informations visuelles à la base de l'analyse du contexte. Je défends ainsi l'idée d'interactions bidirectionnelles précoces entre les traitements visuels ascendants et parallèles de l'objet et du contexte et recherche dans une dernière étude la latence minimale de ces interactions en remplaçant réponse manuelle par réponse oculaire. L'implication de ces résultats fondamentaux est discutée dans la perspective des recherches à venir

Catégorisation rapide des scènes naturelles : L'objet, le contexte, et leurs interactions

In a world governed by physical laws, our brain is able to extract some invariants and to generate expectations to define our visual percept. However, as soon as we turn on the light of a dark room, as soon as we zap to a new tv channel, we understand nearly instantaneously the content of these new complex scenes. How rapidly are we able to extract the gist of natural scenes? Which influence has the context on the recognition of relevant object ? What are the necessary visual information and the underlying visual processing ? The first two papers of this thesis show our capacity to recognize context superordinate categories of natural scenes in less than 400 ms while the access to basic categories needs about 50 ms of additional processing. They reveal also that the presence of salient objects interferes with rapid context categorization. These short processing times that are very similar to those obtained in object categorization tasks suggest a global and parallel processing of the whole scene. The third paper shows that the context congruency with the object immediately influences object categorization processing and the last one analyses the visual information necessary in context processing. Based on such data, I support the idea of early crossed interactions between parallel bottom-up visual processings of object and context. A final study aimed at determining the minimal latency for such interactions by using ocular response rather than manual response. The implications of these fundamental results are discussed in the perspective of future researches.Dans un monde régi par les lois physiques, notre cerveau est capable d'extraire des invariants et de générer des attentes pour préciser notre percept visuel. Pourtant, en éclairant une pièce, ou en naviguant à travers les chaînes de télévision, nous comprenons quasi-instantanément l'essence de ces nouvelles scènes naturelles. A quelle vitesse peut-on extraire une représentation sémantique globale des scènes? Quelle est l'influence du contexte sur la reconnaissance de l'objet d'intérêt? Quelles sont les informations visuelles nécessaires et la nature des traitements sous-jacents? Les deux premiers articles démontrent notre capacité à reconnaître la catégorie superordonnée du contexte d'une scène en moins de 400 ms tandis que l'accès au niveau basique nécessite 50 ms de traitement additionnel. Ils démontrent aussi que la présence d'objets saillants interfère sur la catégorisation rapide du contexte. Ces temps de traitements très similaires à ceux enregistrés dans la catégorisation rapide d'objets suggèrent un traitement global et parallèle de l'ensemble de la scène. Le troisième article montre que la congruence (incongruence) du contexte avec l'objet influence immédiatement le traitement de l'objet et le dernier précise les informations visuelles à la base de l'analyse du contexte. Je défends ainsi l'idée d'interactions bidirectionnelles précoces entre les traitements visuels ascendants et parallèles de l'objet et du contexte et recherche dans une dernière étude la latence minimale de ces interactions en remplaçant réponse manuelle par réponse oculaire. L'implication de ces résultats fondamentaux est discutée dans la perspective des recherches à venir

Catégorisation rapide des scènes naturelles (l'objet, le contexte, et leurs interactions)

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

Early interference of context congruence on object processing in rapid visual categorization of natural scenes

International audienceWhereas most scientists agree that scene context can influence object recognition, the time course of such object/context interactions is still unknown. To determine the earliest interactions between object and context processing, we used a rapid go/no-go categorization task in which natural scenes were briefly flashed and subjects required to respond as fast as possible to animal targets. Targets were pasted on congruent (natural) or incongruent (urban) contexts. Experiment 1 showed that pasting a target on another congruent background induced performance impairments, whereas segregation of targets on a blank background had very little effect on behavior. Experiment 2 used animals pasted on congruent or incongruent contexts. Context incongruence induced a 10% drop of correct hits and a 16-ms increase in median reaction times, affecting even the earliest behavioral responses. Experiment 3 replicated the congruency effect with other subjects and other stimuli, thus demonstrating its robustness. Object and context must be processed in parallel with continuous interactions possibly through feed-forward co-activation of populations of visual neurons selective to diagnostic features. Facilitation would be induced by the customary co-activation of “congruent” populations of neurons whereas interference would take place when conflictual populations of neurons fire simultaneously