Cued Visual Search and Multisensory Enhancement

Previous research has been divided on whether or not multisensory cues can speed visual search relative to their component unisensory cues alone. Some studies (e.g., Mateo et al., 2012) found reaction times for multisensory cues were not faster than the RT of the faster component unisensory cue alone. Other studies (e.g., Oskarsson et al., 2012) found the multisensory cue to be faster than either unisensory cue alone (i.e., multisensory enhancement). This study aimed to determine whether the relative effectiveness match between auditory and tactile cues affects multisensory enhancement on a visual search task. In Experiment 1 we estimated for each subject three auditory cue inaccuracy values that corresponded to RTs equal to, 25% faster than, and 25% slower than tactile cue RTs. In Experiment 2 we combined each estimated auditory cue inaccuracy with a tactile cue to produce the multisensory conditions. We then compared RTs across the three different multisensory conditions. Our results suggest enhancement was more likely to occur when the auditory and tactile cues were closely matched in effectiveness and interference was more likely to occur when auditory and tactile cues were not closely matched. Although additional work will be needed to determine whether the interference was due to ineffective cues, poor strategies by the subjects, or a combination of thee factors, our results seem to demonstrate the utility of providing two equally-matched cues as a strategy to speed visual search

A Computational Model of the Temporal Processing Characteristics of Visual Priming in Search

When people look through the environment their eyes are guided in part by what they have recently seen. This phenomenon, referred to as visual priming, is studied in the laboratory through manipulations of stimulus repetition. Typically, in search tasks, response times are speeded when the same target is repeated relative to when it is changed (e.g., Maljkovic & Nakayama, 1994). Although priming is thought to be based on a memory mechanism in the visual system, there is a debate in the literature as to whether such a mechanism is driven by relatively early (e.g., feature-based accounts) or later (e.g., episodic memory accounts) processing. Across three experiments, this dissertation utilized a computational modeling framework (Systems Factorial Technology; Townsend & Nozawa, 1995) to directly compare early and later accounts of priming and determine when visual priming is processed within the visual system in both feature and conjunctive search tasks. Specifically, priming was assessed in terms of its temporal relation (i.e., parallel or serial) to a relatively early process (the processing of conspicuity) and a relatively later process (the processing of Rewards, Experiment 1a; the processing of Word Cues, Experiments 1b and 2) in the visual system. The results suggest that the priming manipulation is processed in parallel with the conspicuity and word cue manipulations within both singleton (Experiments 1a and 1b) and conjunctive (Experiment 2) search. This supports accounts of priming as an early process and suggest that models of priming as a later process within feature or conjunctive search should be rejected. Further, these results also provide evidence to suggest word cues are processed at early stages of visual processing. This supports models of visual processing that suggest high-level representations can modulate the earliest levels of the visual system. Together, these findings provide some of the strongest evidence about the temporal processing characteristics of priming in visual search to date

Temporal Organization of Color and Shape Processing During Visual Search

The mechanisms guiding visual attention are of great interest within cognitive and perceptual psychology. Many researchers have proposed models of these mechanisms, which serve to both formalize their theories and to guide further empirical investigations. The assumption that a number of basic features are processed in parallel early in the attentional process is common among most models of visual attention and visual search. To date, much of the evidence for parallel processing has been limited to set-size manipulations. Unfortunately, set-size manipulations have been shown to be insufficient evidence for parallel processing. We applied Systems Factorial Technology, a general nonparametric framework, to test this assumption, specifically whether color and shape are processed in parallel or in serial, in three experiments representative of feature search, conjunctive search, and odd-one-out search, respectively. Our results provide strong evidence that color and shape information guides search through parallel processes. Furthermore, we found evidence for facilitation between color and shape when the target was known in advance but performance consistent with unlimited capacity, independent parallel processing in odd-one-out search. These results confirm core assumptions about color and shape feature processing instantiated in most models of visual search and provide more detailed clues about the manner in which color and shape information is combined to guide search

FIBROMATOSIS OF BREAST MIMICKING SARCOIDOSIS

Primary mammary fibromatosis is a rare skin condition which can arise after trauma or previous surgery. The exact etiology is unknown. Very few cases have been reported in literature and the main emphasis is to differentiate this condition from breast carcinoma. We report here an unusual case of a 60 year old female who presented with skin lesion which clinically looked sarcoid with history suggestive of sarcoidosis, but on histopathology fibromatosis of breast was revealed. Complete work up ruled out any carcinomatous changes. Surgical excision of the lesion was done with no recurrence seen in one year follow up period