Reef fish help explain visual perception

8 Dec 2015

Reef fish are helping a University of Queenslandscientist discover how visual tasks such as object recognition and face perception are achieved by the human brain.

The research into how fish analyse and perceive their visual environment, led by School of Biomedical Sciences neuroethologist Dr Ulrike Siebeck, could improve understanding of human visual disorders.

“We know the processing of many complex visual tasks is carried out in the cortex of the human brain, and some of these tasks, such as face recognition, are thought to rely on specialised cells,” Dr Siebeck said.

“What is currently unclear is whether these cells have evolved for the specific task of recognising faces, or whether they have simply learned to recognise faces due to the almost constant exposure.

“The aim of this project is to test how animals without a cortex, such as damselfish, process similar visual tasks and whether tasks such as face recognition can be achieved through learning.” 

Dr Siebeck has discovered that damsel fish look plain yellow to humans but  look colourful to each other.

“Damsel fish have patterns on their faces which reflect ultraviolet light,” Dr Siebeck said.

“Humans can’t see UV light, which is why the fish look plain yellow to us, but to each other they are yellow with UV patterns.

“Each pattern for each fish face is different, like an individual fingerprint, and the fish are very good at discriminating between faces, even when the patterns are manipulated to look very similar through a process called morphing.

“We know the processes used by the human visual system and are interested to see whether fish process patterns in a similar way despite the lack of a cortex.

“We can then use the fish as model to help improve our understanding of human visual perception and the mechanisms of pattern processing, which are important for the understanding of human visual disorders such as prosopagnosia, or object agnosias in general.”

Dr Siebeck is collaborating with computer vision laboratory Matthias Franz in Germany on the next stage of her Australian Research Council-funded research 

“This interdisciplinary project relies on the combination of our skills in computer vision, image analysis, animal behaviour and psychophysics,” she said.

“Using the facial patterns shown to the fish for discrimination, as well as the fish’s decisions of which pattern belonged to which of two categories, Matthias Franz is building a computer model which initially mimics and then predicts the fish’s behaviour.

“Examination of the model will allow us to do a global analysis of the potentially noticeable features used by the visual system of the fish.

Dr Siebeck’s research has featured on the National Geographic website and a paper on the findings of her latest research will be published next year.

Media: Dr Uli Siebeck,, +61 3365 4070; Lynda Flower, School of Biomedical Sciences,, +61 3365 1536.