A greeble is an element of detailing added to an object to break up the surface and add nonfunctional complexity. Greebles are added to objects in movies like the Star Wars series to add the illusion of scale and break up the linear flow of the eye over an object. Now researchers at the Department of Neurological Surgery at the University of Louisville have demonstrated that cognitively normal people who have a genetic predisposition for Alzheimer’s disease (AD) have more difficulty distinguishing among Greebles than individuals without a genetic predisposition. Alzheimer’s is characterized by declining memory, cognition and behavior and is the most prevalent form of dementia. The earlier the disease can be detected, the better. In this study, the researchers identified test subjects age 40-60 who were considered at-risk for AD due to having at least one biological parent diagnosed with the disease. They also tested a control group of individuals in the same age range whose immediate family history did not include AD. The subjects completed tasks in which they were shown sets of four images depicting real-world objects, human faces, scenes and Greebles in which one image was slightly different than the other three. The subjects were asked to identify the image that was different. Individuals in the at-risk group correctly identified the distinct Greeble 78 percent of the time, while the control group correctly identified the odd Greeble 87 percent of the time. Both groups did get better with practice, but the at-risk group lagged behind the control group throughout the process. The researchers believe it would be ideal to have people take this test in their 40s and 50s, and track them for the next 10 or 20 years to see who eventually develops the disease and who doesn’t. The researchers emphasize that they are not proposing that the identification of novel objects such as Greebles is a definitive marker of AD, but believe it may improve early diagnoses in high-risk individuals such as those with a genetic disposition for the disease.