Memory for 'warning' patterns: a link to specific neural excitation

Many animals, called aposematic (AP), exhibit '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 perception, attention and memory in humans, and to explore how the patterns might specifically affect sensory and cognitive function.
Why are warning signals a deterrent to predation? It is well known that some types of pattern (eg. high contrast stripes) cause visual discomfort in some individuals (Conlon 99). It has been proposed that this occurs because such patterning that is highly unusual or anomalous and rarely found in natural scenes. Typical AP patterns (eg high contrast spots/stripes) are similar to patterns that cause visual discomfort. Recent work from our lab (and zoology collaborators from Newcastle), has used a database of lepidoptera patterns to mathematically characterise AP patterns and develop artificial patterns with the same characteristics (Haplin 20). We will use those patterns here.
Studies testing the effects of warning signal patterns in animals suggest that other cognitive function, like memory and learning could be enhanced by AP patterns. Here we will choose humans as our receiver species of study, because we are a generalist predator, and because in humans, perception, attention and memory can be studied using sophisticated techniques. In this project, we aim to use a range of perceptual, attention and memory tasks, along with measurement of eye movements, to behaviourally probe why AP patterns are effective.
The key novel part of the project is to develop a suite of attention and memory tasks that can be used to probe whether the known effects on vision extend to attention and to memory. There are many studies showing how emotionally arousing stimuli can enhance attention. We will use attentional blink or dot-probe techniques to study the temporal limits of attention to warning signal patterns. Standard memory research manipulations at encoding and retrieval, will additionally allow us to determine whether warning signal patterns are more memorable than others, and if so, by what memory mechanisms this increased memorability arises. These insights will be used to adapt a recently developed neural network algorithm to predict what patterns will be memorable (e.g. Isola et al, 2014). We will run such models on warning signal patterns to test for theoretical memorability.
The project is interdisciplinary, bringing together evolutionary biology, experimental psychology and computational neuroscience. It would suit a graduate in neuroscience, zoology, 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. We will develop neural models that can help us understand why the brain delivers these behaviours.