Thursday, 9 April 2015

Predicting responses from MEG-recorded brain activity: A talk by Tijl Grootswagers, J. Brendan Ritchie, and Thomas Carlson (from Macquarie University).

The Cognitive Research Group is proud to host a talk by our visitors from Macquarie University:

Predicting Reaction Times from the Emerging Representation of Degraded Visual Objects.

Tijl Grootswagers, J. Brendan Ritchie, and Thomas Carlson
Macquarie University

ABSTRACT: Object recognition is fast and reliable, and works even when our eyes are focused elsewhere. The aim of our study was to examine how the visual system compensates for degraded inputs in object recognition by looking at the time course of the brain's processing of naturally degraded visual object stimuli. In Experiment 1, we degraded the images by varying the simulated focus so that each image was equally recognizable. In Experiment 2, subjects categorized intact and degraded images, while their brain activity was recorded using magnetoencephalography (MEG). As expected, reaction times for the task were slower for the degraded object stimuli. We assessed several neurally-based models to explain this reaction time difference, including distance-based models, which predict reaction times using distance from a decision bound through neural activation space. We found that the distance-based models were the best predictors, which we also related to the linear ballistic accumulator (LBA) model of choice and reaction time behaviour.

WHEN: Thursday 16th April, 12-1pm.

WHERE: Aviation Building, room AVLG17, with audiovisual link to Ourimbah Science Offices.