An Eastbio funded PhD studentship is available in my lab, co-supervised by Dr. Akira O’Connor.
Memory for ‘warning’ patterns: a link to specific neural excitation
Many animals, called aposematic (AP), exhibit so-called ‘warning signals’, bright patterns that include high contrast, spots or stripes and vivid colours. Although this makes them easier to see, the patterns are thought to have evolved to deter prey, these are the ‘receivers’ who recognise the patterns as being exhibited by animals who are unpalatable or poisonous. The aim of this PhD project is to study the effects of warning signal patterns on attention and memory, and to explore how the patterns might specifically affect sensory and cognitive function.
One question we are addressing is whether there is more to warning signal patterns than simply that they are easy to see. Recent work from computational and behavioural neuroscience suggests an intriguing alternative. We propose that warning patterns may be effective not simply because they are conspicuous, but because they have patterning that is highly unusual or anomalous (described as ‘unnatural’ in ‘vision science’ parlance) because they are rarely found in natural scenes. Such anomalous scenes are processed less efficiently by the brain than more common natural patterns, and evoke greater brain activity in visual areas (e.g. Olshausen et al, 2004). Could the warning patterns of AP prey be sufficiently anomalous that they trigger stronger brain activity than other conspicuous items? There is evidence from studies of human vision that this might occur.
Visual discomfort can arise from looking at certain visual stimuli, such as high-contrast stripy patterns. Although it can disrupt even such everyday tasks as reading a newspaper, the neurological basis for it is not well understood. An emerging idea is that elevated or supressed brain activity is linked to a number of neurological disorders (including depression, epilepsy). AP patterns have the kinds of spatial structure that would make them suited to delivering elevated brain activity. These findings thus suggest a design principle for visual warning colorations: to elicit a distinctive response in the visual system of the receiver, a warning coloration should exhibit visual attributes not typical in natural scenes.
Studies testing the effects of warning signal patterns in animals suggest that memory could be enhanced by AP patterns. Almost no research has been conducted in humans. In this project, we aim to use a range of perceptual, attention and memory tasks, along with measurement of eye movements, to behaviourally probe human neural function.
The project is interdisciplinary, bringing together evolutionary biology, experimental psychology and computational neuroscience. It would suite a graduate in neuroscience, psychology or physical science/engineering. At the end of the project, we will have used a body of tests, from perception, through attention, to memory, to understand how warning signal patterns intrinsically stimulate the human perceptual system.
This project is eligible for the EASTBIO Doctoral Training Partnership: View Website
This opportunity is open to UK nationals (or EU students who have been resident in the UK for 3+ years immediately prior to the programme start date) due to restrictions imposed by the funding body.
Apply by 5.00 pm on 5 December 2016 following the instructions on how to apply at: View Website
Informal enquiries to Prof. Julie Harris (email@example.com) are very strongly encouraged.
Conlon et al (2001) Visual search in migraine and visual discomfort groups. Vision Research, 41, 3063-3068.
Isola et al (2014) What makes a photograph memorable? IEEE Transactions on Pattern Analysis and Machine Intelligence, 36, 1469 – 1482.
Olshausen & Field (2004) Sparse coding of sensory input. Current Opinion in Neurobiology 14, 481.