Category-based Search Research Articles

Category-based attentional guidance can operate in parallel for multiple target objects

The question whether the control of attention during visual search is always feature-based or can also be based on the category of objects remains unresolved. Here, we employed the N2pc component as an on-line marker for target selection processes to compare the efficiency of feature-based and category-based attentional guidance. Two successive displays containing pairs of real-world objects (line drawings of kitchen or clothing items) were separated by a 10 ms SOA. In Experiment 1, target objects were defined by their category. In Experiment 2, one specific visual object served as target (exemplar-based search). On different trials, targets appeared either in one or in both displays, and participants had to report the number of targets (one or two). Target N2pc components were larger and emerged earlier during exemplar-based search than during category-based search, demonstrating the superior efficiency of feature-based attentional guidance. On trials where target objects appeared in both displays, both targets elicited N2pc components that overlapped in time, suggesting that attention was allocated in parallel to these target objects. Critically, this was the case not only in the exemplar-based task, but also when targets were defined by their category. These results demonstrate that attention can be guided by object categories, and that this type of category-based attentional control can operate concurrently for multiple target objects.

Item and category-based attentional control during search for real-world objects: Can you find the pants among the pans?

To compare the speed and efficiency of item-based and category-based attentional control during visual search for real-world objects, we measured N2pc components as electrophysiological markers of attentional target selection. In different blocks, participants searched for 1 or 2 specific target objects or for any object in a target category (items of clothing or kitchen objects). Search displays contained 6 line drawings of different objects, and targets always appeared together with 5 distractors from the other object category. The presence of N2pc components to categorically defined targets demonstrated that category-based search can operate at visuoperceptual processing stages. In contrast to previous findings for letter/digit search (Nako, Wu, & Eimer, 2014), target N2pc components were delayed by 40 ms during category-guided search relative to single-target search. This suggests that for objects and object categories that are less familiar than alphanumerical stimuli, category-guided target selection operates less efficiently than selection that is based on a physical match with an attentional template. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

Capture by object exemplars during category-based search of real-world scenes

Exemplars from cued category selectively interfered with category detection during visual search, independent of spatial location Automatic prioritization of cued over neutral and non-cued categories, suggesting enhancement of the current attentional set Each subject assigned 2 of 3 object categories (people, P; cars, C; trees, T) in counterbalanced manner, one of which was cued on every trial Phase I: initiate robust attentional sets for 2 task-relevant categories

Searching for Something Familiar or Novel: Top–Down Attentional Selection of Specific Items or Object Categories

Visual search is often guided by top-down attentional templates that specify target-defining features. But search can also occur at the level of object categories. We measured the N2pc component, a marker of attentional target selection, in two visual search experiments where targets were defined either categorically (e.g., any letter) or at the item level (e.g., the letter C) by a prime stimulus. In both experiments, an N2pc was elicited during category search, in both familiar and novel contexts (Experiment 1) and with symbolic primes (Experiment 2), indicating that, even when targets are only defined at the category level, they are selected at early sensory-perceptual stages. However, the N2pc emerged earlier and was larger during item-based search compared with category-based search, demonstrating the superiority of attentional guidance by item-specific templates. We discuss the implications of these findings for attentional control and category learning.

How Do Users Search the Mobile Web with a Clustering Interface?

Category-based search result organization holds promise as a means of facilitating mobile information access. This paper presents the results of a longitudinal user study that investigated how a mobile clustering interface is used to search the Web. The author describes the participants’ search behavior and discusses the benefits and limitations of category-based result access. Study results show that category-based interaction was considered situationally useful, for example when the participants had problems describing their information need or needed to retrieve a subset of results. The paper proposes design guidelines for category-based mobile search interfaces. These include improved strategies for presenting the categories in the search interface, the need to improve the categorization methods to provide more representative category structures, and accounting for the contextual aspects of mobile information needs.

Recommendation of e-commerce sites by matching category-based buyer query and product e-catalogs

In this paper, an e-commerce site recommendation system that integrates multiple e-commerce sites is proposed. This system provides the users with a unified portal through which the users can search individual suppliers’ product categories efficiently. The core part of the system is an intelligent product meta-search engine that has the following functions: (1) it provides category-based query, with which a buyer can describe his or her product search intention using superclass/subclass relationship, (2) by using WordNet, the buyer's query is semantically extended in order to increase product search accuracy, and (3) the meta-search engine decides a recommended priority of the suppliers by matching the buyer's query with the suppliers’ product categories and computing a semantic relevancy measure. Experiments show that the performance of the meta-search is better than those of general keyword-based search and category-based search.