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Virtual Reality – Real Insight August 8, 2017

Posted by Jon Ward in Advertising, eye tracking, Market Research, Shopper Research, Technology, Updates.
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Imagine the excitement, akin to a Christmas morning as the UPS delivery driver gets you to sign for the box that contains a thing of beauty, your shiny new VR headset. But this is no ordinary VR headset, oh no – not for you – master of all your survey, keeper of the technology, King or Queen of the early adopters! This is a VR headset with a built in eye tracker, and you are ready….. ready to dive into far off lands, explore supermarkets on the other side of the world and measure your virtual driving skills around the race track and then take over the world and….. hang on… wait a minute…. what are these instructions saying? “download the SDK and API and integrate it into your own platform….” but….. but….I don’t have time for this I have worlds to dominate! We hear you and we have the solution to your problem.

The current crop of eye tracking integrations into VR supply you with an API and SDK, and maybe some example code to stream and save data into Unity, WorldViz or similar… but not much else, and while some of the coders out there get excited about this blank canvas our experience is that most people want something they can work with pretty much right away. But it isn’t quite that easy.

Unlike screen based or glasses based eye tracking software where you have a lot of known parameters (the website is on screen and it is http://www.acuity-ets.com, or I know the user was shopping in Tesco in Croydon and this is what the shelf looked like), with VR you could be flying a spaceship down a canyon on Mars, or walking through a prototype Apple store in Singapore via a brief trip to a coffee shop to take part in a social science project. The boundless flexibility of virtual reality presents a challenge, it is almost impossible to create a platform that covers everything anyone might want to do in VR. ALMOST impossible.

At Acuity we have over 10 years’ experience in using eye tracking at the coal face, whether that is selling systems, running research, troubleshooting and advising on R&D or helping people go beyond the heatmap and get real value from the data and we know that people aren’t going to be happy with just an SDK for their new VR headset – they want more. So we made AcuityVR.

AcuityVR is a module designed to work with new or existing Unity assets, meaning that your existing investment in models can be reused, or you can build new ones and we have some amazing content partners we can recommend, if you don’t have in-house capabilities. We don’t ask you to change the way you do things, so if you use controllers for interaction then that’s fine; if you have enough space for people to walk your VR environment – not a problem for AcuityVR. The way we have designed it means that you can drop the code into a driving simulator, a walkthrough of a train station, a virtual pet grooming salon, a retail store, a clinical simulation or…. well just about anything!

We wanted to make the product a logical step from current eye tracking platforms on the market so you will see all the usual functionality in place – you can live view sessions and see the eye gaze as your participant moves around the environment; we have gaze replays, heat maps, opacity maps and statistical analysis of areas of interest – and all of these for single or multiple users. But VR gives us so much more opportunity – how about replaying multiple users at the same time while you view the environment from different angles and when you notice interesting behaviour simply switch to that persons point of view? Add multiple camera views to give different vantage points throughout the journey and view behaviour from 1st or 3rd person perspectives. We also measure and track footfall, dwell time and direction of journey – ideal for wayfinding and layout planning. Of course, being Acuity we know that eye-tracking data requires some specialised algorithms to turn data-points into fixations, and so we took care of that too, so you don’t need a PhD in eye-movements to make sense of the data.

One of the key benefits of research in VR is that you control the entire environment and this provides a number of benefits that simply can’t be matched in real world testing. Firstly every single item in an environment can be automatically classed as an AOI. That’s right, no more drawing little boxes or creating key frames. Every item in the environment can automatically have statistical data captured. In real time. If a person engaged with something you didn’t expect, no problem AcuityVR already has the stats. Measure fixations, glances, average fixations durations and time to first fixation instantly. Want to re-use the dataset for POS instead of product interaction, sure – the data is already there and rea   dy to go! All of our visualisations, replays, stats and other tools are available instantly after the session is finished – no more waiting for days for coding, number crunching or exporting image and videos. This leads to both time and cost efficiencies in research, design cycles and implementing change.

VR allows you to control the world (well, at least the virtual world – actual global domination comes later!) – imagine the possibilities of being able to dynamically change environments. Turn a daytime driving simulation into night instantly, then add some fog or a thunder storm. Take products out of stock off the shelf or change pricing in real time. Have an avatar respond negatively to the user by not making eye contact with them. Use 3D audio to totally immerse the user…. the possibilities are endless within VR, and eye tracking adds a whole new dimension for optimisation, interaction and research capabilities in virtual environments. But without a tool to capture and anlyse the data, all that potential can prove difficult to achieve. AcuityVR is that tool.

Give us a call, drop us an email or maybe send us a virtual hello at sales@acuity-ets.com or visit http://www.AcuityVR.com for more.

 

There is an Eye in Motion (Capture) July 24, 2017

Posted by Jon Ward in Biometric, eye tracking, Glasses, Technology, Tobii.
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We are very excited to announce that Tobii and Qualisys have released a direct integration between the market leading Tobii Glasses 2 eye tracking system and the Qualisys QTM software platform. This exciting partnership means that eye tracking data can be plotted like any other data type in QTM and as well as visualisations gaze vector data can be exported to MATLAB or similar, or captured in an external source via the real-time streaming protocol. In addition the hardware sync the integration starts both the glasses and cameras simultaneously for incredibly accurate synchronisation of the data streams and I am sure you will agree that for gait analysis, sports science, gaming, behavioural analysis, psychology and more this news is incredibly exciting.

As you can see from the above image as well as the standard vector models if you use the Opus camera system you get the ability to overlay the 3D overlay over live video to really bring your research to life!

To download the PDF click here : Tobii and Qualisys Integration and don’t hesitate to get in with any questions you might have or to find out more.

The Great Eye Tracker Amnesty! June 30, 2017

Posted by Jon Ward in eye tracking.
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Over the nearly 10 years Acuity ETS have been around there have been a number of eye tracking companies that have appeared in the ever-expanding market space and that is great for consumer choice and competition, however unfortunately not all of them survive and others are purchased or merge into other companies to be integrated into hopefully bigger and better things. Some of course cease trading or change focus – and that isn’t great for the users of their equipment.

Eye tracking equipment comes in at many prices points, users of the $100 Eye Tribe system were angered when the company was bought and they instantly closed down all support for their products, well what if that had been a £20,000 professional eye tracking system that you had to struggle to get budget for and is now obsolete, unsupported or even worse – broken.

Tobii have always offered an upgrade path for their users, so that your existing hardware can be traded in and a generous discount given off the new equipment, it has proven hugely popular with some of our customers on their 3rd or 4th system, always keeping ahead of the curve with the latest technology. But this has always been a ‘same brand’ option – Tobii for Tobii. But that’s not how it works in other walks of life right? You can part-ex your car against a different brand for example, the same with a mobile phone – so why not an eye tracker?

Well now you can, we are offering customer the opportunity to trade in their screen based or wearable eye trackers and software to receive a discount off a new Tobii system, and we are opening it up to all recognised manufacturers, so if you have an Eye Tribe or an ASL, an Eyelink or a SMI then give us a call. Even if you want to cross platforms and go to wearable from a screen based system, we can help you out – and academic discounts apply on top of the trade in.

Get in touch – we would love to hear from you!

 

The Apple of Your Eye? June 28, 2017

Posted by Jon Ward in eye tracking, Tobii.
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The newswires are buzzing along with the fact the SMI (our biggest competitor in the market place you might suggest) have been purchased by Apple for reasons currently unknown, at least publically. So what does this mean for the industry, for Tobii, and of course customers and users of their technology.

Firstly, from a technology perspective this is a hugely positive thing. While Apple typically lock down their infrastructure and architecture to their app store, hardware and OS the fact they have made a move to buy one of the larger players in the field reinforces the fact the eye tracking is a technology on the rise, one that will only increase its presence in our daily life. If we look at Facebook’s acquisition of Eye Tribe (via Oculus) and Google purchasing Eyefluence all of the big tech players are buying into eye tracking. In a big way. Whether it is for research purposes, interaction or to optimise hardware performance there is obvious value and ROI by including eye tracking and everyone is getting on board.

From  Tobii’s perspective it can be seen two ways. The obvious one is “Hooray!” one of the biggest competitors we see on a daily basis are no longer around, so of course we would hope to serve more customers and we are confident that we have the technology, products and capability to ensure their needs are met. From the other angle, not having someone just around the corner, pushing you, innovating, driving you to develop can be a bad thing. Google had Yahoo (at one stage!) amongst other suitors to the throne, Apple had Microsoft (or vice versa) and Commodore had Sinclair (retro throwback for some!) – these rivalries help push things forward, to be the best and without that driver you need to push yourself. Am I confident that Tobii will do this? Yes. Why? Because we feedback our thoughts and ideas regularly into design and planning meetings, we collate requests from our customers and pass that on and the team in Sweden and beyond are committed to eye tracking across all markets – from gaming interaction to research, from VR to accessibility.

A little more of a grey area is where does this leave SMI’s customer base? Will Apple continue to sell research products? I doubt it. Their other acquisitions have all been absorbed into the behemoth from Cupertino. What about support? Software updates? Repairs? How about people who have just purchased or are about to purchase a system? I am sure with time there will be more information released and maybe some long-term planning to cover all these aspects. At Acuity we would be happy to help out where we can, of course we would be keen to sell people a new system or assist with a quote (in fact we are also pleased to offer a trade in for existing SMI users to upgrade their systems to one of the Tobii platforms, with access to support, updates and future innovations), but we will happily help with other enquiries, we have experience with SMI’s BeGaze software and we are happy to talk metrics and methodologies so why not get in touch!

Keeping an Eye on Education June 7, 2017

Posted by Jon Ward in eye tracking, Technology, Tobii.
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Eye tracking is widely used across many fields of academia and in the commercial world as a tool for research, training, behavioural analysis and gathering insight. However, until now equipping a lab with research quality equipment and market leading analytical software has been expensive, meaning that classrooms or lab set-ups are limited to one or two systems, and users often fight for time with the equipment to complete their projects, or miss out on the powerful data that can be gathered from eye tracking.

Acuity and Tobii have teamed up to create a unique solution offering powerful functionality, maximum flexibility and outstanding value for institutes wanting to offer eye tracking to their students. This enables departments such as psychology, marketing, economics, neuroscience and computing to equip multiple research workstations in a simple and cost effective manner.

The set-up allows students to run individual projects, work in groups or teams and of course to participate in a single project that can be analysed centrally as well as locally. This flexibility allows people to work at their own pace or be led by a teacher, and allows tailored studies to be run to accommodate users with specific requirements – such as colour blindness or dyslexia – without excluding them which could happen with a ‘group’ style single test that is pushed out to all users, as with some other solutions.

You can fully explore and understand human behaviour, information gathering, decision making, emotional processes and much more using high quality, research grade eye tracking systems without compromising on analysis capabilities! Every workstation has a full software suite allowing them to design, present, record, review and analyse the data, meaning everyone has access to the powerful analytical tools, not just a central licence or moderator.

Users can create static and animated visualisations of interactions and run statistical analysis. They can combine this with mouse movements, key presses, user camera video, flagged observations and audio recordings across a wide range of stimulus including websites, video, images, PDF’s, questionnaires and external video sources.

The solution is fully scalable from ten units to an unlimited number of workstations, and can be upgraded or expanded at any time, and all our solutions come with expert on-site training and support.

We can tailor a proposal to the size and scale of your requirements, and offer advice on infrastructure, lab configuration and integration with existing equipment. Contact us at sales@acuity-ets.com or on +44 1189 000795.

Neuro-Tools : Heart Rate & Respiration November 21, 2016

Posted by eyetrackrob in Biometric, Captiv, eye tracking, Market Research, Marketing, neuromarketing, TEA, Technology, Uncategorized.
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Although not as fast as I thought, step by step, I’ll be covering the most relevant biofeedback sensors in this blog series. So far I’ve only managed to write about GSR, one of the sensors of the hour! Galvanic Skin Response has been around for a long time and in the past years it has gained lots of attention from researchers, but as you might have read in my last post, although it deserves all the attention it gets, it’s not always that simple to use.

Other measurements mentioned before that could tell you more about emotions or cognitive workload are respiration, heart rate and from this also the possibility to calculate the variability of the heart rate (HRV).

Heart Rate

Heart Rate (HR) reflects the frequency of a complete heartbeat within a specific time window. It is typically expressed as beats per minute (bpm). The HR is constantly, antagonistically influenced by the sympathetic nervous system (SNS) and parasympathetic nervous system (PsNS) and in general heart rate, similar to GSR, unfolds rather slowly. Although with peak effects observed after 4 seconds and return to baseline after about 20 seconds it is much slower than GSR. Heart Rate Variability (HRV) on the other hand expresses the quick variations of the frequency between heart beats. The time between beats is measured in milliseconds (ms) and is called an “R-R interval” or “inter-beat interval (IBI).”

ecg-signal

Image 1: shows a typical heart rhythm as recorded by an electrocardiogram (ECG). You can see heart rate (4bpm) as well as the differences in the inter-beat intervals.

Both measurements (HR and HRV) are closely related to emotional arousal, with HRV allowing for assessment of more sensitive and quicker changes, which also can be related to stress and cognitive workload (this might be a good topic for a follow up post).

While today many fitness devices exist that measure heart rate in the context of fitness and well being, those solutions might not be the ideal for your research. One of the reasons for this is the processing and averaging of data going on in the sensor.

fitness-monitor slide1

Image 2: shows the same recording as averaged data export (blue) and as it was displayed during the recording (orange). The data was recorded with a wrist worn device measuring the HR optically using light. In the averaged data the highest heart rate is at around 100 bpm. In the live stream the same time frame shows much more variability (still averaging at around 100 bpm) and it’s clearly visible that it is not the highest value of the recording.

 

As mentioned above, heart rate has a relatively low sensitivity and slow response. Many wearable fitness trackers don’t allow to export the data for further analysis or allow to access only averaged data, where quick spikes in the data have been eliminated as noise. The result of this prepossessing of data is that the effects of emotion might be lost altogether. On the other hand to compute HRV correctly, continuous and precise measurements must be guaranteed. Just 2-3 missed data points can mean inaccurate calculations of the times between beats and thus again missing relevant events.

slide21

Image 3: In the live visualization the highest heart rate reaches 145bpm. However the suspiciously round form reaching to the peak value indicates that data points are missing and data was interpolated. This becomes clear when looking at the averaged data. This data would not be suited for interpretation of HR or HRV.

Another reason why many heart rate trackers available for fitness purposes are not necessarily a suitable solution for researchers is that most of them are worn on the wrist and use light to measure blood flow and from there derive the heart rate. Compared to sensors that are placed close to the heart and measure electrical impulses (electrocardiogram/ECG), sensors on the wrist have to overcome challenges of compensating for movements, muscle-tensing, sweating and potentially light interference. ECG sensors are therefore the recommended tool for data collection for research purposes as they are more sensitive to certain signal characteristics.

ecg-beltecg-electrodes

Image 4: ECG Sensor as belt or as electrodes

Respiration

Research has associated respiration rate and depth with emotional impact and emotional valence. Interestingly olfactory information ascends directly to limbic areas and is not relayed through the thalamus as other sensory input. The Thalamus is a part of the brain which is acting as a relay and pre-processing for sensory information and is accounted to be relevant to regulate consciousness, arousal, wakefulness and alertness. As olfactory information is not relayed through this part of the brain, there is a different mechanism to make olfactory information conscious which leads to quicker physiological response and unconscious alternation of the respiratory pattern. Respiration patterns therefore allow to identify potentially unconscious liking or disliking and arousal. The deduction of a unique emotion from respiration rate and depth does not seem to be possible although more research is still needed in this area.

Respiration measurements can be obtained either from the use of dedicated clinical instruments, stretch sensitive respiration belts or can be calculated from ECG data. The latter being the least invasive for commercial research.

t-sens-respi-belt

Figure 6. Stretch Sensitive Respiration Belt

ECG data can be processed in TEA Captiv to obtain HR, HRV and even respiration rate and as with GSR all of the mentioned measurements can be synchronized with eyetracking to understand what visual information influenced a rise in HR, a change in HRV or an alteration of respiration patterns.

In my next post I’ll take a look at how all these measurements can be combined and if through a combination it is possible to not only detect emotional events but also understand whether it is a positive or negative emotion and even which specific emotion it is. So, watch this space for more!

 

Copy Cat Brands – Who is Trying to Steal Your Attention? October 31, 2016

Posted by Jon Ward in Advertising, eye tracking, Market Research, Marketing, neuromarketing, Shopper Research.
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Tim from Acuity has recently been speaking at a conference in Peru where he presented some of the exciting findings from our parasitic brands research last year. Using the world leading facilities at the GSK SSL and in partnership with the British Brands Group we tested people’s recognition of famous brands and their not-so-famous imposters under a variety of conditions. Have a watch of the video below and maybe head over to the Acuity Intelligence website and read more about the study here : http://www.acuity-intelligence.com/blog/statute-of-imitations

 

Tobii Eyetracking & Garmin GPS/ANT+ Data for Sports and Real-World Wayfinding Research October 31, 2016

Posted by Scott Hodgins in Biometric, eye tracking, Glasses, Tips And Tricks, Tobii, Uncategorized.
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In Jon’s previous blog post he mentioned me running and training with some friends over at Forest Fit Clubs and added a video link. I wanted to reply to the inevitable questions about data overlays etc. and how did we do this with the Tobii software? The short answer is that we didn’t, here’s a “how to” to get you started.

This version is based on a running, other examples include:

  •  Wayfinding – overlay GPS data on the eyetracking video so you can immediately see where pedestrians moved in the built environment. Understanding how people use signage, do they see it? do they understand and use it?
  • Driving & Flying – use the GPS and speed/G-Metrix data to understand the technique and relationships between looking-engaging and acting on that information.
  • Data overlay’s are not just limited to the Garmin descriptions – you can hack the overlays to change the title and add maybe GSR data, or cognitive data and arousal metrics from an EEG such as the ABM X-10

Overview.
We wanted to show the power of adding basic data overlays onto the eyetracking video so we could easily associate an action from the video with a resultant change in data. We had a Garmin VIRB XE that we had used for a technical demonstration with a customer. I had noticed that the VIRB produced MP4 files, as did the Tobii Glasses 2 (TG2), so the idea of hacking the workflow, swapping the VIRB video out and overlaying biometric and location data over the TG2 video data was born. Below is a video showing an overview of the software.

The kit list:
1 x Tobii Glasses 2 (any variant)
1 x Garmin Fenix 2 Sports watch (now replaced by the Fenix 3 and Fenix 3 HR, which may be an alternative source for HRM data)
1 x Garmin HRM RUN Heart rate monitor, we wanted this as it also offered specific run data, not just HR
1 x Garmin VIRB XE & Garmin VIRB Edit Software (we didn’t use the camera, just the software)
1 x Willing participant (me, and yes I calibrated myself, in daylight, outside, it is super-easy with the TG2) with a suitable pocket or running belt to stash the recording unit in.

The steps:

  1. Assemble the TG2:
    Connect Head Unit-Cable-Recording Unit, Insert SD Card, Insert Battery & power up. This took about 5 minutes instead of the normal 2 minutes as I threaded the cable under my base layer to control the cable movement and placed the recording unit in a neoprene running belt to control movement. (1)
  2. Power up the controlling computer, we use Dell Venue 11 Pro’s (Now Dell Latitude 11 5000) running W7 Pro or W10 Pro x64.
  3. Connect to the TG2 WLAN, start Tobii Glasses Controller, select “New Recording”, add a participant name and description.
  4. Calibrate: Select the icon in the bottom right of the screen to calibrate (easy on the tablet – just touch) and look at the calibration marker – for non Tobii users a fully 3D calibration is completed typically <5s. A major advantage of this ground-breaking 3D calibration model is that we don’t have to try and “work around the data” during analysis. (2)
  5. Start the recording, then start the recording on the Garmin Fenix while looking at the screen – it’s not perfect but we should be able to sync the data to the frame where the recording started and at 25fps video we are sure that we are sync’d to about 40ms. (3) Turn the laptop off, or put it in sleep mode.
  6. Run around, enjoy the beautiful scenery at Somerley.
  7. Finish session, cool down, stretch – up to 90 minutes per battery so we have plenty of time head back to the car and stop the recording on both the Garmin Fenix and the TG2
  8. Stopping the recording, then select the recording and start to output the 1080p HD video.
  9. Sync Garmin to the cloud – in this case it was Bluetooth to Garmin Connect on my iPhone then auto sync’d to the cloud (connect.garmin.com)
  10. Login to your connect account, select the activity and download the FIT or GPX data from this session.
  11. Open VIRB Edit, create a new video and import the video you exported from the Tobii Glasses Controller, then add this to the video timeline.
  12. Import the FIT or GPX data, click on G-Metrix and then on Data and find your file.
  13. Sync the two files using one of the options at the foot of the G-Metrix>Data dialogue.
  14. Now use either the Templates and Gauges options to add data overlays on to the video, you can use appearance to change the colour of the gauges.
  15. Importing the logo & setting up a new template is more art than science – good luck with that, I think it took me about a dozen failed attempts then it magically worked, I took the time to try again while writing this, it now shows as a Beta function in the software.
  16. Export the video to your chosen resolution and quality.

The next post will look at doing something similar, using TEA Captiv as a more scientific option, with multiple video feeds and more data options.

The end result:

Notes:

  1. It is worth taking 5 minutes here to make sure you have free movement before starting, otherwise turning too sharply could lead to disconnection or discomfort. Because I used the wireless version, once I was wired up and adjusted I didn’t need to touch the system again until I was retrieving data.
  2. Other wearable/head mounted eyetrackers have issues when we start looking in different planes. Their calibration model is typically a one dimension transform that is adequate when looking in the calibrated plane, the calibration will suffer when looking in a different plane. For example if we calibrate on a vertical wall (looking at the corners of a picture) then place that picture flat on the desktop we will see trapezoidal offsets, this is also true if we calibrate in a horizontal plane (desk) and look at a vertical target (wall). The result is that if we are not cognoscente of this and take the distorted (erroneous) data at face value we risk producing worthless results.
  3. There is a sync port on the Tobii that can send/receive an LVTTL pulse to/from an external device, however the Garmin watch isn’t designed for this so we chose to keep it simple with a video based sync.
  4. Garmin data formats, I have always used the GPX download to import into VIRB Edit, the FIT data caused a few anomalies specifically with time and GPS origin. The FIT file has all of the data recorded in Garmin Connect, the GPX has less, there was still enough for this example though.

Neuro-Tools : GSR October 24, 2016

Posted by eyetrackrob in Biometric, Captiv, eye tracking, Glasses, Market Research, neuromarketing, TEA, Tobii, Uncategorized.
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As mentioned in my first introduction to this blog, the central nervous system is divided into different branches which monitor and control different body functions. One of the branches, the sympathetic nervous system (SNS), is responsible for quick fight or flight reactions. By constantly accessing the surroundings and scanning for situations that could potentially be dangerous an evaluation takes place which leads to preparations for an adequate fight or flight reaction. These preparations can be measured throughout the body and include changing heart rate, respiration and levels of sweat on hands and feet.

As we start to understand that these non-conscious reactions are strongly and inseparably tied to decision making processes and thus human behaviour, more and more researchers have become interested in using tools to measure these reactions.

In my first post a few weeks ago, I wrote about the general rise of Neuro-Tools and mentioned some such as eyetracking, EEG, facial expression analysis, GSR, heartrate and respiration as well as Implicit Association Tests as examples. The series aims to go through these tools one by one and review what they measure, how they work and of course also where we run into the limitations of those tools. With the general objective to give you a perspective on how these tools can be made a valuable addition for your research, I’d like to continue the series looking at GSR today. Initially I thought of talking about GSR, heartrate and respiration in this post as they could easily be summarized as “biometrics” or “biofeedback measurements”, but it turned out to be a quite long post, so I’ll split them down into individual posts.

Enough of the introductions! Let’s dig into the exciting world of biometrics starting with:

Galvanic Skin Response

GSR isn’t simply around measuring sweat, there is an awful lot more to it than that so before offering some general advice on what to look out for when considering to use GSR, I would like to explain the basics around this tool.

Electrodermal Activity (EDA), Skin Conductance (SC) or Galvanic Skin Response (GSR) refer to the ability of the skin to conduct electricity due to changes in the activity of the sweat glands and thus the secretion of sweat. Those changes are closely related to psychological processes and can be triggered by emotional stimulation. Electricity can be conducted when an external, unnoticeable current of constant voltage is applied, and with more moisture on the skin, electrical resistance decreases and skin conductance increases at a measurable level, although sweat might not necessarily be visible through visual observation.

Skin conductance can be divided into tonic and phasic activity. The level of conductivity of the tonic activity is constantly changing within each individual respondent, depending on their hydration, skin dryness and autonomic regulation in response to environmental factors such as temperature for example. Phasic response in turn are short term peaks in GSR reflecting reactions of the SNS to emotionally arousing events, mostly independent of the tonic level. For most of the time, we will be looking at these reactions which occur in the eccrine sweat glands.

GSR data is measured in microsiemens (μS) and the relevant phasic reactions can be quantified and analysed in different ways. Apart from the number of peaks occurring within a certain period after stimulus onset, peak amplitude, the time to reach peak value and the recovery time can be used for analysis. GSR can be used to determine strength of arousal but can’t be used to determine the valence (like or dislike) of a reaction.

eda-example

Image 1 is an example of data including tonic and phasic activity.

 

The density of sweat glands varies across the body being highest on the head, the palms and fingers as well as on the sole of the feet. Most tools that measure the GSR are therefore build to be used on the fingers, where this reaction is strongest. However some instruments on the market allow for measuring the change in sweat levels on the wrist which often results in poorer data quality but might be necessary for some experiments where the hands are needed to interact with objects (i.e. holding mobile devices/products or typing).

 

eccrine-sweat-glands-distribution-2

 

Image 2 shows eccrine sweat gland concentration. Red areas indicate a high concentration of eccrine sweat glands (glands.cm−2) allowing to measure sympathetic arousal of low intensity and minimal duration. Green zones indicate a low concentration of relevant sweat glands able to measure only events of high intensity (for example on the wrist). (N. Taylor; C. Machado-Moreira, 2013

 

Depending on the manufacturer and kind of system used for the measurements, sensors can be adhesive electrode pads that are already filled with conductive gel in order to reduce preparation time and to avoid electrode movement. Conductive gel is not mandatory but can improve data quality and ensure a good and stable electrical connection. Many GSR device manufacturers that provide systems for the use on fingers and toes, provide Velcro straps to place the electrodes firmly. In any case excessive respiration, movements and talking should be avoided as these can cause noise in the data or variations in the signal that can be misinterpreted.

tsensgsr           e4-front_light

Image 3 shows a classic sensor (TEA T-Sens GSR) that can be placed on the fingertips adjustable with velcro straps next to an Empatica E4 wristband. 

 

As written in the introduction, reaction times and strength are highly individual and therefore distinct for each participant and they can vary between 400 milliseconds up to 5 seconds after presenting a stimulus. In a controlled lab environment a calibration procedure can help to understand individual differences in reactions but might not always be necessary. It is not advised to use GSR in areas where many low and high impact events can occur uncontrolled at any time and can be mixed with all kinds of artifacts, as it might be complex, if not impossible, to relate an emotional arousal peak to a specific event.
If free movement is a requirement (for example in shopper research) it is highly recommended to calibrate the GSR reaction time and strength for each participant and to complement the GSR measure with a synchronized video and sound feed -ideally even with eyetracking- to understand the source of the arousing events. The synchronization of several feeds can sometimes be a challenge but there are solutions that allow either for a live synchronization or a post-recording-synchronization.

 

tea-synch

Image 4 shows a synchronized recording of different sensors such as ECG, HR, HRV, Respiration and Cogntitive Workload with eyetracking (top right) and an additional video stream (bottom right). The synchronization can be done for example using the QR code that is visible on the screen (top left) marking a synchronization point in video and sensor feed.  

 

t-log

Image 5 shows a TEA T-Log, a small and mobile device that emits a short flash of light that can be picked up by a camera or in the video of the Tobii Glasses marking a visible event in the video and a sync point in the sensor recordings.

 

How GSR raw data, filtered data and emotion detection works all synchronized with eyetracking, can be seen in the following short video, recorded from TEA Captiv. I also imported data from a wrist-worn GSR device but the data was not usable, which is why I chose to minimize those curves in the software.  As you can see in Image 2 the concentration of eccrine sweat glands on the wrist is low which very often means having a very noisy signal or the absence of a signal. To improve the signal quality it is recommended to get a minimum level of tonic sweating, for example through some physical exercises. Although I did this (as you can indirectly and briefly see at the very beginning of the video), it wasn’t enough to make the measurement from the wrist usable. For these types of study (researching and improving the emotional and visual impact of TV commercials), I would usually recommend to use a remote eyetracker such as the Tobii X2-60 as well as sensors worn on the fingers (T-Sens GSR or similar), however I also wanted to show that it can easily be done with a mobile eyetracker if needed as shown below:

 

In comparison you can also watch a video of a similar test (same commercials) using a remote eyetracker as mentioned above. You’ll notice similarities in the general gaze data but also in the arousal detection, although you might also notice that each participant has a slightly different reaction time and  the emotional threshold has an influence on how many emotional moments each person is experiencing:

 

There is still a bit more to know about GSR and we at Acuity are do offer training on methodologies, technology and best practices for your research. To give you a headstart on some of the things to consider have a think about these 4 questions and then maybe give us a call:

  1. Where will the data collection happen? Do you need to be completely mobile, or will it be a controlled environment close to a computer? If you go mobile, can you carry a small device to record the data or does the GSR device itself needs to store the data?
  2. What type of sensor do you need? Is it a viable option to use sensors on the fingers, or will you need to use the hands to hold something or type for example?
  3. Do you know how to analyse the data? GSR raw data is rarely usable. Do you know how to remove the effects of tonic activity and artifacts and do you need a software that can do it for you and find the relevant events?
  4. Do you need to synchronize the data with other devices and do you want to accumulate data over several participants?

In the next post I’ll be covering heart rate and respiration to wrap up the more commonly used biofeedback tools before taking on EEG, facial expression analysis, Implicit association tests and others. Stay tuned!

 

3D – The Key to Tobii’s Performance Lead October 17, 2016

Posted by Scott Hodgins in eye tracking, Glasses, Market Research, Marketing, Media, neuromarketing, Shopper Research, Technology, Tips And Tricks, Tobii, Updates, Usability & UX.
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This post is trying to answer some of the most common questions that we get asked – Why should I buy a Tobii? Why is it better? System “X” has a “better head box” and system “Y” is cheaper.

The answer from our point of view is simple, the eyetracking is more accurate than using other systems for more people over a longer timeframe.

This is a pretty grand claim, why are we so confident?

Let’s start at the beginning; Eyetracking itself is straight forward, there are several well documented methods to find and follow the pupil, Tobii uses a non-intrusive video based technique called “Pupil Centre Corneal Reflection” (PCCR). Essentially an IR illuminator is used to help differentiate between the pupil and the iris, it also creates a highlight or glint that we use as well. The Tobii systems use an improved version of this idea, the secret-sauce as it were being a combination of two things, illumination and data modelling. These two areas allow the remote and wearable trackers to monitor the respondents relative 3D position in space, adjust the calibration parameters in the 3D physiological model, and therefore afford a far greater range of movement than similar systems while keeping accuracy and precision.
(Figure below shows the native 3D data from the TG2)

3d-head-coord-tobii

Illumination: Tobii can use up to two different lighting techniques known as bright and dark pupil to optimise the illumination for the participant in that location, and crucially when they move we can adapt the illumination to keep track of them. This allows a Tobii to offer people greater freedom of movement while retaining the tracking accuracy without the need for constant drift correction from the system operator.

Data modelling: The Tobii method is different having typically used multiple cameras in their research grade eyetrackers and have done since the launch of the T and X series systems in 2007/8. The advantage of using multiple cameras is that we can physically describe the location of the eye in space. That is to say we know with a very high degree of accuracy where the centre of your eye is, and which eye it is, for every sample recorded. The slightly different images from the pair of cameras in an X2 for example allows the creation of a 3D physiological model of the eyes it is tracking during calibration. This approach allows Tobii to understand the movement of the eye or the eyetracker should one or the other move and adjust the calibration accordingly with a high degree of precision.

The net result is that the these systems can accommodate movement, even if the head leaves the area trackable by the hardware and can recover tracking when the eyes are visible again, this is one of the reasons people keep choosing Tobii for demanding applications like infant research and in-vivo commercial research. In a recent study Acuity Intelligence recruited 330 people as they were entering supermarkets and didn’t have to turn away a single participant because they could not be tracked – a first for any data collection exercise with this number of people regardless of the brand of technology they were using.

Don’t just take out word for it, please challenge us, whether it is onscreen, in the real world or in the emerging AR and VR application areas we can help.