Much of the work in the lab centres on how we recognise objects and how we integrate different visual attributes into a coherent visual percept. We also study selective attention across space and time domains and how selective attention influences object processing. We use a variety of techniques, including behavioural experiments with normal individuals (typically 1st year Psychology students), neuropsychological investigations of patients with brain lesions, trasncranial magnetic stimulation (TMS) and some forms of brain imaging (e.g. fMRI, MEG).
This is an umbrella project, comprising a number of specific studies and student projects. In this line of research we use the technique known as rapid serial visual presentation (RSVP), in which stimuli are presented sequentially one after another at a rate of about 8-10 items per second. Several processing limitations are elicited under these conditions, including repetition blindness (i.e., the inability to detect a repeated stimulus in the stream) and the attentional blink (i.e., the inability to detect a second target item for about 500ms after selecting a first target from the stream of stimuli).
The study of these effects can reveal what happens in very early stages of visual processing, between initial registration of a stimulus and its consolidation into visual short-term memory, and the processes by which a stimulus is individuated, or perceived consciously as a separate visual episode. We exploit these phenomena to try to understand the mechanisms involved in visual identification of a variety of stimuli (objects, faces, words).
These studies are conducted primarily in collaboration with Paul Dux, Will Hayward and Sally Andrews and are supported by funding from the ARC, the Research Grants Council of Hong Kong and the University of Sydney.
The issue of how we recognise objects across changes in viewpoint has been a matter of intense research and debate for nearly three decades, yet we are still a long way from understanding how the visual system achieves this task. In this project, we approach this question from the position that object recognition proceeds in a number of stages which are differentially affected by orientation: an early pre-conscious stage, in which the visual input activates an object representation stored in memory, and a later stage, in which the object’s identity is placed in a spatial reference frame, in order to create a conscious visual episode of the object as seen at a particular moment. The aims of the project are 1) to uncover the characteristics of these two processing stages, particularly with respect to the role played by viewpoint information and 2) to relate these to underlying neural processes, through the study of neurological patients and TMS.
This project aims to elucidate how feature and holistic information interacts with attention, by assessing the relative importance of feature and holistic representations in recognition without awareness and attention, as indexed by object priming and repetition blindness phenomena, as well as under full attention conditions. This work is also done in collaboration with Will Hayward and Claire Benito and is supported by a grant from the University of Sydney.
This project is primarily conducted by Claire Benito as part of her PhD. It investigates whether spatial and temporal attention are distinct constructs with distinct processing resources or whether they share the same resource pool.
In collaboration with Evan Livesey and Justin Harris, we are looking at implicit learning during the attentional blink and at how acquired stimulus relevance and associations, in turn, modulate the attentional blink.
|2012-2014||ARC Discovery Grant – “Ensemble coding of complex visual stimuli” (I.M. Harris) – $210,000.|
|2010-2013||ARC Future Fellowship – “Seeing the forest and the trees: Cognitive and neural mechanisms underlying the recognition of individual objects and sets” (I.M. Harris) – $674,000.|
|2008-2009||Research Grants Council of Hong Kong – “Recognizing repeated objects in rapid visual streams” (CI’s: W. G. Hayward, I.M. Harris) – HK$806,000.|
|2008-2010||ARC Discovery Grant – “The ingredients of conscious identification” (I.M. Harris, S. Andrews, W.G. Hayward) – $302,000.|
|2006||University of Sydney Research & Development Grant – “The role of features and holistic information in object recognition” (CI: I.M. Harris) – $21,000.|
|2005-2009||ARC Discovery Grant and Queen Elizabeth II Fellowship – “Recognition of rotated objects: paying attention to orientation” (I.M. Harris & M.C. Corballis) – $600,000.|
|2003-2005||Research Grants Council of Hong Kong – “An investigation of the independence of mental rotation and viewpoint-dependent object recognition” (W.G. Hayward, I. Gauthier, I.M. Harris) – HK$726,500.|
|2003||Macquarie University Early Career Researcher Grant – “Repetition blindness for rotated objects: insights into the nature of object representations” (I.M. Harris) – $18,200.|
|2002||Macquarie University Research Grant – “Lateralisation of function in the human brain” (T. Bates & I.M. Harris) – $4,350.|
|2002-2004||ARC Discovery Grant and Australian Postdoctoral Fellowship – “Recognising the orientation of objects: a combined neuropsychological / eye movement investigation” (I.M. Harris) – $204,000.|