Gaze and power. A post-structuralist interpretation on Perseus’ myth

Gaze hierarchizes, manages and labels reality. Then, according to Foucault, gaze can be understood as a practice of power. This paper is inspired by his theories, and it applies them to one of the most powerful symbolic spheres of Western culture: Greek Myths. Notions such as visibility, invisibility and panopticism bring new light into the story of Perseus and Medusa, and they enable a re-reading of this Myth focused on the different ways of power that emerge from the gaze.

Using time-to-contact information to assess potential collision modulates both visual and temporal prediction networks

Accurate estimates of the time-to-contact (TTC) of approaching objects are crucial for survival. We used an ecologically valid driving simulation to compare and contrast the neural substrates of egocentric (head-on approach) and allocentric (lateral approach) TTC tasks in a fully factorial, event-related fMRI design. Compared to colour control tasks, both egocentric and allocentric TTC tasks activated left ventral premotor cortex/frontal operculum and inferior parietal cortex, the same areas that have previously been implicated in temporal attentional orienting. Despite differences in visual and cognitive demands, both TTC and temporal orienting paradigms encourage the use of temporally predictive information to guide behaviour, suggesting these areas may form a core network for temporal prediction. We also demonstrated that the temporal derivative of the perceptual index tau (tau-dot) held predictive value for making collision judgements and varied inversely with activity in primary visual cortex (V1). Specifically, V1 activity increased with the increasing likelihood of reporting a collision, suggesting top-down attentional modulation of early visual processing areas as a function of subjective collision. Finally, egocentric viewpoints provoked a response bias for reporting collisions, rather than no-collisions, reflecting increased caution for head-on approaches. Associated increases in SMA activity suggest motor preparation mechanisms were engaged, despite the perceptual nature of the task.

Background beliefs and evidence interpretation

In this paper we argue that it is often adaptive to use one’s background beliefs when interpreting information that, from a normative point of view, is incomplete. In both of the experiments reported here participants were presented with an item possessing two features and were asked to judge, in the light of some evidence concerning the features, to which of two categories it was more likely that the item belonged. It was found that when participants received evidence relevant to just one of these hypothesised categories (i.e. evidence that did not form a Bayesian likelihood ratio) they used their background beliefs to interpret this information. In Experiment 2, on the other hand, participants behaved in a broadly Bayesian manner when the evidence they received constituted a completed likelihood ratio. We discuss the circumstances under which participants, when making their judgements, consider the alternative hypothesis. We conclude with a discussion of the implications of our results for an understanding of hypothesis testing, belief revision, and categorisation.

A comprehensive study of visual cryptography

In this survey, we will summarize the latest developments of visual cryptography since its inception in 1994, introduce the main research topics in this area and outline the current problems and possible solutions. Directions and trends for future VC work shall also be examined along with possible VC applications.

Secure masks for visual cryptography

In this journal article, we take multiple secrets into consideration and generate a key share for all the secrets; correspondingly, we share each secret using this key share. The secrets are recovered when the key is superimposed on the combined share in different locations using the proposed scheme. Also discussed and illustrated within this paper is how to embed a share of visual cryptography into halftone and colour images. The remaining share is used as a key share in order to perform the decryption. It is also worth noting that no information regarding the secrets is leaked in any of our proposed schemes. We provide the corresponding results in this paper.