Filter by type:

Sort by year:

Beating the bookies with their own numbers - and how the online sports betting market is rigged

Journal Paper
Kaunitz L, Zhong S, Kreiner J


The online sports gambling industry employs teams of data analysts to build forecast models that turn the odds at sports games in their favour. While several betting strategies have been proposed to beat bookmakers, from expert prediction models and arbitrage strategies to odds bias exploitation, their returns have been inconsistent and it remains to be shown that a betting strategy can outperform the online sports betting market. We designed a strategy to beat football bookmakers with their own numbers. Instead of building a forecasting model to compete with bookmakers predictions, we exploited the probability information implicit in the odds publicly available in the marketplace to find bets with mispriced odds. Our strategy proved profitable in a 10-year historical simulation using closing odds, a 6-month historical simulation using minute to minute odds, and a 5-month period during which we staked real money with the bookmakers. Our results demonstrate that the football betting market is inefficient – bookmakers can be consistently beaten across thousands of games in both simulated environments and real-life betting. We provide a detailed description of our betting experience to illustrate how the sports gambling industry compensates these market inefficiencies with discriminatory practices against successful clients.

Optokinetic nystagmus reflects perceptual directions in the onset binocular rivalry in Parkinson’s disease

Journal Paper
Fujiwara M.*, Ding C.*, Kaunitz L., Stout J. C., Thyagarajan D., Tsuchiya N.
PLoS ONE 12(3): e0173707

* Equal contribuition


Optokinetic nystagmus (OKN), the reflexive eye movements evoked by a moving field, has recently gained interest among researchers as a useful tool to assess conscious perception.
When conscious perception and stimulus are dissociated, such as in binocular rivalry — when dissimilar images are simultaneously presented to each eye and perception alternates between the two images over time—OKN correlates with perception rather than with the physical direction of the moving field. While this relationship is well established in healthy subjects, it is yet unclear whether it also generalizes to clinical populations, for example, patients with Parkinson’s disease. Parkinson’s disease is a motor disorder, causing tremor, slow movements and rigidity. It may also be associated with oculomotor deficits, such as
impaired saccades and smooth pursuit eye movements. Here, we employed short-duration, onset binocular rivalry (2 s trial of stimulus presentation followed by 1 s inter-trial interval) with moving grating stimuli to assess OKN in Parkinson’s disease patients (N = 39) and controls (N = 29) of a similar age. Each trial was either non-rivalrous (same stimuli presented to both eyes) or rivalrous, as in binocular rivalry. We analyzed OKN to discriminate direction of stimulus and perception on a trial-by-trial basis. Although the speed of slow-phase OKN was slower in the patients, discriminability of conscious perception based on OKN was comparable between the groups. Treatment with anti-Parkinson drugs and deep brain stimulation improved motor ability of patients, but did not impact on OKN. Furthermore, OKN-based measures were robust and their latencies were shorter than manual button-based measures in both groups and stimulus conditions. To our knowledge, our study is the first to demonstrate that OKN can be used as a reliable indicator of conscious perception in binocular rivalry even in Parkinson’s disease patients in whom impaired manual dexterity may render button-press reports less reliable.

Large capacity of conscious access for incidental memories in natural scenes

Journal Paper
Kaunitz L., Rowe E., Tsuchiya N.
Psychological Science doi: 10.1177/0956797616658869 · August 9, 2016


When searching a crowd, people can detect a target face only by direct fixation and attention. Once the target is found, it is consciously experienced and remembered, but what is the perceptual fate of the fixated nontarget faces? Whereas introspection suggests that one may remember nontargets, previous studies have proposed that almost no memory should be retained. Using a gaze-contingent paradigm, we asked subjects to visually search for a target face within a crowded natural scene and then tested their memory for nontarget faces, as well as their confidence in those memories. Subjects remembered up to seven fixated, nontarget faces with more than 70% accuracy. Memory accuracy was correlated with trial-by-trial confidence ratings, which implies that the memory was consciously maintained and accessed. When the search scene was inverted, no more than three nontarget faces were remembered. These findings imply that incidental memory for faces, such as those recalled by eyewitnesses, is more reliable than is usually assumed.

Late EEG responses are absent for conscious but task-irrelevant stimuli

Journal Paper
Navajas, J. and Kaunitz L.
Journal of Neuroscience 36 (1): 4-6 · January 2016


Scholarly review of Shafto and Pitts.

Saccade kinematics modulate perisaccadic perception

Journal Paper
Fracasso A.*, Kaunitz L.*, Melcher D.
Journal of Vision, 15(3):4, 1-12 · March 2015
*Equal contribution


Around the time of execution of an eye movement, participants systematically misperceive the spatial location of briefly flashed visual stimuli. This phenomenon, known as perisaccadic mislocalization, is thought to involve an active process that takes into account the motor plan (efference copy) of the upcoming saccade. While it has been proposed that the motor system anticipates and informs the visual system about the upcoming eye movements, at present the type and detail of information carried by this motor signal remains unclear. Some authors have argued that the efference copy conveys only coarse information about the direction of the eye movement, while a second theoretical view proposes that it provides specific details about the direction, amplitude, and velocity of the saccade to come. To test between these alternatives, we investigated the influence of saccade parameters on a perisaccadic unmasking task in which performance in discriminating the identity of a target (face or house) followed by a trailing mask is dramatically improved around the time of saccade onset. We found that the amplitude and peak velocity of the upcoming saccade modulated target perception, even for stimuli presented well before saccadic onset. We developed a predictive model for the generation of the efference copy that incorporates both saccade amplitude and saccade velocity planning prior to saccade execution. Overall, these results suggest that the efference copy stores specific information about the parameters of upcoming eye movement and that these parameters influence perception even prior to saccade onset.

Waves of visibility: probing the depth of inter-ocular suppression with transient and sustained targets

Journal Paper
Kaunitz L., Fracasso A., Skujevskis M. and Melcher D.
Front. Psychol. 5:804. doi: 10.3389/fpsyg.2014.00804 · July 2014


In order to study non-conscious visual processing, researchers render otherwise consciously perceived images into invisible stimuli. Through the years, several psychophysical techniques have been developed for this purpose. Yet the comparison of experimental results across techniques remains a difficult task as the depth of suppression depends on the interactions between the type of stimuli and the suppression methods employed. This poses a limit to the inferences that researchers make about the extent of non-conscious processes. We investigated the mechanisms underlying inter-ocular suppression during continuous flash suppression (CFS) and dichoptic visual masking using a transient onset target stimulus and a variety of stimulus/mask temporal manipulations. We show that target duration, timing of target onset, and mask frequency are key aspects of inter-ocular suppression during CFS with transient targets. The differences between our results and sustained target CFS studies suggest that two distinct mechanisms are involved in the detection of transient and prolonged target stimuli during CFS. Our results provide insight into the dynamics of CFS together with evidence for similarities between transient target CFS and dichoptic visual masking.

Looking for a face in the crowd: Fixation-related potentials in an eye-movement visual search task

Journal Paper
Kaunitz L., Kamienkowski J., Varatharaja A., Sigman M., Quian-Quiroga R., Ison M.
Neuroimage, 89, 297-305 · December 2013


Despite the compelling contribution of the study of event related potentials (ERPs) and eye movements to cognitive neuroscience, these two approaches have largely evolved independently. We designed an eye-movement visual search paradigm that allowed us to concurrently record EEG and eye movements while subjects were asked to find a hidden target face in a crowded scene with distractor faces. Fixation event-related potentials (fERPs) to target and distractor stimuli showed the emergence of robust sensory components associated with the perception of stimuli and cognitive components associated with the detection of target faces. We compared those components with the ones obtained in a control task at fixation: qualitative similarities as well as differences in terms of scalp topography and latency emerged between the two. By using single trial analyses, fixations to target and distractors could be decoded from the EEG signals above chance level in 11 out of 12 subjects. Our results show that EEG signatures related to cognitive behavior develop across spatially unconstrained exploration of natural scenes and provide a first step towards understanding the mechanisms of target detection during natural search.

Non-conscious processing of motion coherence can boost conscious access

Journal Paper
Kaunitz L., Fracasso A., Lingnau A., Melcher D
PLoS ONE 8(4): e60787 · April 2013


Research on the scope and limits of non-conscious vision can advance our understanding of the functional and neural underpinnings of visual awareness. Here we investigated whether distributed local features can be bound, outside of awareness, into coherent patterns. We used continuous flash suppression (CFS) to create interocular suppression, and thus lack of awareness, for a moving dot stimulus that varied in terms of coherence with an overall pattern (radial flow). Our results demonstrate that for radial motion, coherence favors the detection of patterns of moving dots even under interocular suppression. Coherence caused dots to break through the masks more often: this indicates that the visual system was able to integrate low-level motion signals into a coherent pattern outside of visual awareness. In contrast, in an experiment using meaningful or scrambled biological motion we did not observe any increase in the sensitivity of detection for meaningful patterns. Overall, our results are in agreement with previous studies on face processing and with the hypothesis that certain features are spatiotemporally bound into coherent patterns even outside of attention or awareness.

Unseen complex motion is modulated by attention and generates a visible aftereffect

Journal Paper
Kaunitz L., Fracasso A., Melcher D.
Journal of Vision, 11(13):10, 1–9 · November 2011


The relationship between attention and awareness and the processing of visual information outside of attention and awareness remain controversial issues. We employed the motion aftereffect (MAE) illusion and continuous flash suppression (CFS) to study the behavioral effects of unseen and unattended visual motion. The main finding was that either withdrawal of attention or the lack of visual awareness on the adaptors did not eliminate the formation of translational MAEs, spiral MAEs, or the interocular transfer of the MAE. However, no spiral MAE was generated when attention was diverted from the unseen spiral adaptors. Interestingly, all MAEs that arose in the absence of awareness or in the absence of attention were reduced in size. The pattern of results is consistent with suggestions that the magnitude of visual motion adaptation depends on both attention and awareness.

Intercepting the first pass: rapid categorization is suppressed for unseen stimuli

Journal Paper
Kaunitz L., Kamienkowski J., Olivetti E., Murphy B., Avesani P. and Melcher D.
Front. Psychology 2:198. doi: 10.3389/fpsyg.2011.00198 · August 2011


The operations and processes that the human brain employs to achieve fast visual categorization remain a matter of debate. A first issue concerns the timing and place of rapid visual categorization and to what extent it can be performed with an early feed-forward pass of information through the visual system. A second issue involves the categorization of stimuli that do not reach visual awareness. There is disagreement over the degree to which these stimuli activate the same early mechanisms as stimuli that are consciously perceived. We employed continuous flash suppression (CFS), EEG recordings, and machine learning techniques to study visual categorization of seen and unseen stimuli. Our classifiers were able to predict from the EEG recordings the category of stimuli on seen trials but not on unseen trials. Rapid categorization of conscious images could be detected around 100 ms on the occipital electrodes, consistent with a fast, feed-forward mechanism of target detection. For the invisible stimuli, however, CFS eliminated all traces of early processing. Our results support the idea of a fast mechanism of categorization and suggest that this early categorization process plays an important role in later, more subtle categorizations, and perceptual processes.

Backward masking and unmasking across saccadic eye movements

Journal Paper
De Pisapia N., Kaunitz L., Melcher D.
Current Biology, 20, 1-5 · March 2010


Humans make several eye movements every second, and thus a fundamental challenge in conscious vision is to maintain continuity by matching object representations in constantly shifting retinal coordinates. One possible mechanism for visual stability is the remapping of receptive fields around saccade onset, combining pre- and postsaccadic information. The mislocalization of stimuli briefly flashed near the time of saccades has been taken as evidence for remapping. Yet the relationship between remapping, mislocalization, and trans-saccadic integration remains unclear. We asked participants to identify a target stimulus presented around the time of saccade onset, which was immediately visually masked by a postsaccadic stimulus presented in the same spatial location (backward masking). Presenting two rapidly occurring events across separate fixations allowed us to investigate how the visual system reconstructs what happens during a saccade. We show that saccadic remapping resulted in perception of target and mask as either spatially segregated or integrated, depending on the exact timing of saccade onset. During segregation, the target was unmasked because it was perceived as displaced from the mask; during integration, the postsaccadic stimulus masked the presaccadic target (spatiotopic masking). Thus, segregation and integration may work together to yield continuity in conscious vision.