top of page

My research tackles the behavioral and neural correlates of unconscious and conscious processes. I am particularly interested in understanding the complexity of unconscious processes and how conscious and unconscious processes interact. I am also deeply intrigued by a relatively newly discovered class of photoreceptors, ipRGCs. What are the functions of these sluggish photoreceptors in humans? More recently, I have begun to utilize the change of implicit processing in older individuals to identify early cognitive deficits.

The relationship between attention and consciousness
Task load gates unconscious semantic processing. Are unconscious processes automatic and "attention-free?" Here we show that unconscious word semantic processing is gated by the load of a concurrent conscious task (LINK). 
Aging, Alzheimer's, and implicit interference

Clifford et al. 2012 Lancet Neurology

Stronger implicit interference in high-risk older individuals. In the early stages of Alzheimer's, there is a long cognitive normal period where individuals' cognition seems unaffected. Finding a biomarker during this period is key for early intervention. In a recent study, we found that a behavioral marker, implicit interference, correlated
with cognitively healthy older individuals' risk level. Specifically, high-risk, but not low-risk, individuals suffered from an implicit yet distracting preceding prime. (LINK) (Caltech news article). More recently, we found that additional attention generated by practice leads to stronger implicit interference in high-risk individuals but weaker interference in low-risk counterparts (Practice makes imperfect).
How complex, integrated are unconscious processes?
Complexity of unconscious processes. Are unconscious processes shallow and low-level or seemingly high-level, integrated processes can occur unconsciously? Through multiple studies, we show that syntax (PDF, a more recent one LINK.), crossmodal mapping (PDF​), and facial attractiveness (LINK​) can all be processed prior to stimulus conscious awareness. More recently, we show that our visual system gathers probabilistic information from unconscious stimuli over multiple incidences (LINK).  
Neural underpinnings of (un)conscious processes
Mind wandering in sensory cortices. The neural underpinnings of mind wandering, a ubiquitous experience to everyone, have been gradually revealed with brain imaging techniques. Among others, default mode network (DMN) stands out as a candidate. Here we took a different approach to probe the phenomenal experiences during mind wandering. We asked: Do sensory contents in mind wandering give rise to activity in the sensory cortices? (LINK)
Non-visual melanopic excitation leads to discernible changes in the frontal cortex. What occurs when indistinguishable lights stimulate our retina? To be more specific, what if these lights triggered a third class of photoreceptors in the eyes? Here we show that the typical eye movement/attention network is triggered by stimulating melanopsin-containing ganglion cells. (PDF)
bottom of page