 Very humbled and extremely happy to have won I'm a Scientist 2016 for the Astatine Zone... I'm a scientist is a Wellcome Trust supported venture that gets school kids chatting with scientists.
This is not an actual winners speech... but I was asked to write a few words about the experience. The text is available on the website, but also below: Hi everyone! I was extremely happy to be the winner of the Astatine Zone for I’m A Scientist, Get me out of here! It was a pretty manic few weeks but the spectrum and quality of the questions was really something special: I was so impressed that so many young scientists were asking questions from consciousness and AI… to robotics, the universe and beyond! I had to really dig deep to answer some of them, and I wish I had the opportunity to be involved with a platform like this when I was younger! Thank you again to all the students who asked questions, and also a big thank you to Andres, Sam, Ellie & Catherine for helping me to learn about stuff too! Whilst I loved every single question that I had to deal with, I was seriously impressed by how contemporary the questions were. I was consistently asked about artificial intelligence, robotics and the challenge of getting a robot to become aware of itself! These are big questions that are super relevant right now! I was even more impressed that students thought about the ethical implications of creating sentient artificial life systems! So hopefully the future is in good hands…! Now that my time answering questions is up (and I have no idea how I answered them all!) I will be thinking about how to spread the word of neuroscience, psychology, and statistics past this superb forum for interaction between scientists and students. I have the idea to start a video blog to provide resources to explain scientific concepts for anyone who wants to listen! I will probably have a monthly ‘Open Challenge’ for students (or anyone for that matter!) to ask me to explain something regarding neuroscience and psychology! I am passionate about talking to anyone who wants to listen about science. I really want to challenge the idea that a lot of science is ‘beyond’ people with no scientific training. I read a lot of scientific work that is filled with over-complications and jargon: I want to simplify the stuff I know and chat about it with you guys! Finally, I want to say thank you again too all the staff, mods, students and teachers that were involved these past few weeks. It’s been an absolute pleasure and I hope to hear some more questions from students again in the future! It’s been such a cool experience, and I hope everyone took away as much from this as I did! Keep asking questions! Darren
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New research, using a Bayesian inference model of audio and visual stimuli, has shown how our perception of time lies mid-way between reality and our expectations. 90 participants were tested across four experiments, and asked to report on the timing of the last event in a regular sequence of beeps or flashes. The findings, published in Scientific Reports, displayed that participants anticipated future occurrences of the stimuli in line with the regular pattern, but the perceived accuracy of their response differed from reality when the stimuli was either accelerated or delayed. If the timing was regular, participants were able to anticipate the stimulus. However, when the final stimulus was delivered early, the participants perceived that it had occurred ‘only slightly earlier’ than expected, around halfway between their predicted response and the reality. Similarly, when the final stimulus was delivered late, the participants had a similar perception of halfway between their prediction and the reality. The researchers, from the universities of Birmingham and Sussex, believe their findings suggest that humans do not perceive time as it really is – rather as a mid-way between reality and their expectations. These findings suggest that the brain continuously updates the probability of encountering future stimuli based on prior experiences. Dr Max Di Luca, from the University of Birmingham, explained, “Our brain relies on past events to predict what will happen next. These predictions are essential to survival because they allow us to react faster to the environment around us and plan what actions to perform.” “Our perceptions are also affected by these predictions; they are the result of the combination of our expectations and actual sensory information. We don’t perceive the world as it really is, or as we expect it to be, but somewhere in between.” “Imaging a bad musician playing a cover version of one of your favourite songs. You have an expectation of which notes to expect and when to expect them. Even when poorly performed, your expectations will help ‘soften the blow’ and make it sound relatively better. However, if you were listening to them play a song you had never heard before, you would have no real expectations and so every mistimed note would be evident.” Dr Darren Rhodes, now at the University of Sussex, added, “We are not passive watchers. We use what we know about the world to inform us about when something is likely to happen. If our predictions are slightly wrong, we perceive the world somewhere in between expectation and reality. We hear, see and feel what we think we should be experiencing, not what is really happening out there.” “The conclusions that that can be drawn from this research can be applied to several technological domains” says Dr Di Luca. “Knowing how the brain predicts the world can be used to teach robots how to behave and think in a way similar to humans, for example,” says Dr Rhodes, who is working at a European-funded project on the interaction between neuroscience and robotics. Dr Di Luca is currently spending his sabbatical at Oculus. Original Publication: Massimiliano Di Luca & Darren Rhodes: Optimal Perceived Timing: Integrating Sensory Information with Dynamically Updated Expectations was published in Scientific Reports on Jul 7, 2016 and is available here: www.nature.com/articles/srep28563, with the DOI: doi:10.1038/srep28563  Humans are not passive observers of time. In a new paper in Scientific Reports, myself and Max Di Luca show how temporal expectations bias time perception. We use a combination of psychophysics and Bayesian modelling to really probe how the timing of events changes due to the expectations we build from the statistics all around us.
We show that if you present stimuli slightly earlier or later than expected, then the perceived timing of events is shifted closer to expectation. Interestingly, we also find a repulsive effect - stimuli presented perfectly on-time are actually (subjectively) reported as being earlier in time. We model this asymmetry in the results with an iterative-update Bayesian model with asymmetric probability distributions. I have used the terms 'perceived timing' and 'subjective reports' interchangeably above - and with good reason. Further work by our lab will try to elucidate whether the changes we have observed are due to the perception of time changing at the encoding level – or at a decision stage. I imagine the truth will (as usual) be somewhere in between. Please get in touch if you want to chat about this work. In a recent article by Martin Riemer, Myself and Thomas Wolbers published in Neural Plasticity we uncovered evidence that uncertainty about the timing of intervals is independent of temporal reproduction.
Martin has published a few papers recently along the idea of time being the 'view from nowhen', That is, due to the way time flows, there are necessary peculiarities when measuring temporal properties. A common finding in the literature is that, on average, subjects reproduce intervals as slightly shorter than what they are. This is usually called the 'negative error', and has been explained by Martin as due to a general judgment bias towards earlier responses, instead of reflecting a genuine misperception of temporal intervals. We applied transcranial magnetic stimulation (TMS) to inhibit neuronal processes in the right posterior parietal cortex (PPC) and tested its effects on time discrimination and reproduction tasks. The results show increased certainty for discriminative time judgments after PPC inhibition. They suggest that the right PPC plays an inhibitory role for time perception, possibly by mediating the multisensory integration between temporal stimuli and other quantities. Importantly, this increased judgment certainty had no influence on the degree of temporal underreproduction. We conclude that the systematic underreproduction of time is not caused by uncertainty for temporal judgments. Paper can be found here: A few months ago, Myself, Susan Li and Max Di Luca published a paper in Timing & Time Perception that showed how the perceived timing of events in a sequence of regularly-timed tones is not perfect. That is, to perceive tones as being 'on time' you have to present them slightly later than regular timing (Figure top panel). Things presented on time are not perceived as being on time. This is quite surprising and counterintuitive, and indeed is opposite to what most models of time perception predict. This means that stimuli presented 'on time' are actually perceived slightly earlier, as such we suggest they are actually perceptually accelerated... Why? Well if you believe in things like entrainment and the active sensing framework, then when temporal attention is directed towards a particular point in time, the increase in attentional resources facilitates the perception of things encountered at the expected time, and as such, gives them a little kick forward (Figure, bottom panel). We also found that temporal sensitivity to temporal irregularities increases as the amount of stimuli in a sequence increases. This is not a new finding, and has been reported lots of times in different ways... however, in this paper, we compared different models of temporal sensitivity, and formulated some interval based models to be predictive about the perceived (event) timing of events. We find that actually, most of the models are mathematically the same, but they cannot deal with formulating estimates of temporal sensitivity and perceived timing. Maybe a new model is needed that can model both the perceived timing and temporal sensitivity of events....? Obvious foreshadowing there. A pre-print of this paper is found in the 'Publications' page of this website for more technical summaries of the models and methods used in this paper.  So for quite a long time, I have been thinking that the time perception community really needs a conference to itself. Usually, 'time' gets lumped on at the end of other conferences and that's the end of that. Now, the wonderful Argiro Vatakis and Sundeep Teki have put together a new society for promoting multidiscplinary research on timing and time perception: The Timing Research Forum. This is a massive step in the right direction, and follows on from the wonderful work Argie did with the 'TIMELY' initiative. TIMELY ran for a few years, and allowed researchers to come together and talk about time. I personally benefitted from some great workshops by some top guys in the field. So I am super happy this has been translated to a real society. Membership is free so register if interested!   So I thought it was probably a good idea to start a blog about what I do... and what others are doing. I intend to broadly comment on papers that have come out recently on the subject of time perception - but I will probably add in one or two things that are more disparate.
I encourage discussion of mine and others work in an environment that is open. I am a signatory of the open science initiative (https://opennessinitiative.org) and really want to have cool chats with people about what we do. Hope you all have a great day - and look forward to chatting some more. Darren |
Darren RhodesTrying to work out how robotics can predict the future Archives
December 2016
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