Facilitating exploratory search by model-based navigational cues

ABSTRACT We present an extension of a computational cognitive model of social tagging and exploratory search called the semantic imitation model. The model assumes a probabilistic representation of semantics for both internal and external knowledge, and utilizes social tags as navigational cues during exploratory search. We used the model to generate a measure of information scent that controls exploratory search behavior, and simulated the effects of multiple presentations of navigational cues on both simple information retrieval and exploratory search performance based on a previous model called SNIF-ACT. We found that search performance can be significantly improved by these model-based presentations of navigational cues for both experts and novices. The result suggested that exploratory search performance depends critically on the match between internal knowledge (domain expertise) and external knowledge structures (folksonomies). Results have significant implications on how social information systems should be designed to facilitate knowledge exchange among users with different background knowledge

Memory versus Perceptual-Motor Tradeoffs in a Blocks World Task

Using information in-the-world as external memory may be a low-cost alternative to internal memory: storage is free, and retrieval is often quick (involving a saccade) and reliable. However, when the cost of accessing external information increases, in-the-head storage and retrieval may become the least-cost solution. We employ the rational analysis framework (Anderson, 1990) to study the effect of varying the cost of information access on interactive behavior. Increasing the cost of information access induced a switch from information in-the-world (the perceptualmotor strategy) to information in-the-head (the memory strategy). Given the effort and unreliability of internal storage, the threshold for switching from an in-the-world to an in-the-head strategy is surprisingly low