Sam Schwarzkopf
@sampendu.bsky.social
Kiwified neuroscientist & perception researcher at the School of Optometry & Vision Science at Waipapa Taumata Rau | University of Auckland, Aotearoa New Zealand. Lab website: sampendu.net
#UltimaDragon
#UltimaDragon
Pinned
Reminder to submit Symposia & Workshops
for #epc-apcv-2026 by 31 Jan 2026!
Also announcing keynotes:
- Hakwan Lau (IBS, South Korea
- Elaine Reese (Uni of Otago, NZ
- Corey Wadsley (Uni of Auckland, NZ)
visualneuroscience.auckland.ac.nz/epc-apcv-2026
#psychscisky #visionscience #neuroskyence
for #epc-apcv-2026 by 31 Jan 2026!
Also announcing keynotes:
- Hakwan Lau (IBS, South Korea
- Elaine Reese (Uni of Otago, NZ
- Corey Wadsley (Uni of Auckland, NZ)
visualneuroscience.auckland.ac.nz/epc-apcv-2026
#psychscisky #visionscience #neuroskyence
Very proud and pleased that Poutasi Urale, the first PhD student I supervised since starting in Auckland has now graduated! Good way to start the holidays! 🙂🎓
(And no, this is not my academic gown...)
(And no, this is not my academic gown...)
December 14, 2025 at 11:17 PM
Very proud and pleased that Poutasi Urale, the first PhD student I supervised since starting in Auckland has now graduated! Good way to start the holidays! 🙂🎓
(And no, this is not my academic gown...)
(And no, this is not my academic gown...)
Reminder to submit Symposia & Workshops
for #epc-apcv-2026 by 31 Jan 2026!
Also announcing keynotes:
- Hakwan Lau (IBS, South Korea
- Elaine Reese (Uni of Otago, NZ
- Corey Wadsley (Uni of Auckland, NZ)
visualneuroscience.auckland.ac.nz/epc-apcv-2026
#psychscisky #visionscience #neuroskyence
for #epc-apcv-2026 by 31 Jan 2026!
Also announcing keynotes:
- Hakwan Lau (IBS, South Korea
- Elaine Reese (Uni of Otago, NZ
- Corey Wadsley (Uni of Auckland, NZ)
visualneuroscience.auckland.ac.nz/epc-apcv-2026
#psychscisky #visionscience #neuroskyence
December 8, 2025 at 11:33 PM
Reminder to submit Symposia & Workshops
for #epc-apcv-2026 by 31 Jan 2026!
Also announcing keynotes:
- Hakwan Lau (IBS, South Korea
- Elaine Reese (Uni of Otago, NZ
- Corey Wadsley (Uni of Auckland, NZ)
visualneuroscience.auckland.ac.nz/epc-apcv-2026
#psychscisky #visionscience #neuroskyence
for #epc-apcv-2026 by 31 Jan 2026!
Also announcing keynotes:
- Hakwan Lau (IBS, South Korea
- Elaine Reese (Uni of Otago, NZ
- Corey Wadsley (Uni of Auckland, NZ)
visualneuroscience.auckland.ac.nz/epc-apcv-2026
#psychscisky #visionscience #neuroskyence
If you calculated noise ceilings (NC) based on split-half reliability - e.g. to compare models - this one is important!
Seems many published studies miscalculated it, overestimating model performance. First, let's make this crystal clear:
NC = 2*r / (1+r)
where r is split-half correlation.
Seems many published studies miscalculated it, overestimating model performance. First, let's make this crystal clear:
NC = 2*r / (1+r)
where r is split-half correlation.
New preprint w/ Malin Styrnal & @martinhebart.bsky.social
Have you ever computed noise ceilings to understand how well a model performs? We wrote a clarifying note on a subtle and common misapplication that can make models appear quite a lot better than they are.
osf.io/preprints/ps...
Have you ever computed noise ceilings to understand how well a model performs? We wrote a clarifying note on a subtle and common misapplication that can make models appear quite a lot better than they are.
osf.io/preprints/ps...
OSF
osf.io
December 8, 2025 at 12:51 AM
If you calculated noise ceilings (NC) based on split-half reliability - e.g. to compare models - this one is important!
Seems many published studies miscalculated it, overestimating model performance. First, let's make this crystal clear:
NC = 2*r / (1+r)
where r is split-half correlation.
Seems many published studies miscalculated it, overestimating model performance. First, let's make this crystal clear:
NC = 2*r / (1+r)
where r is split-half correlation.
It is our great honour to announce the APCV Keynote at #epc-apcv-2026: Prof. Hakwan Lau from the Institute for Basic Science in Korea!
The call for member-initiated symposia & abstracts is now open: visualneuroscience.auckland.ac.nz/epc-apcv-2026
#psychscisky #visionscience #neuroskyence
The call for member-initiated symposia & abstracts is now open: visualneuroscience.auckland.ac.nz/epc-apcv-2026
#psychscisky #visionscience #neuroskyence
November 23, 2025 at 9:11 PM
It is our great honour to announce the APCV Keynote at #epc-apcv-2026: Prof. Hakwan Lau from the Institute for Basic Science in Korea!
The call for member-initiated symposia & abstracts is now open: visualneuroscience.auckland.ac.nz/epc-apcv-2026
#psychscisky #visionscience #neuroskyence
The call for member-initiated symposia & abstracts is now open: visualneuroscience.auckland.ac.nz/epc-apcv-2026
#psychscisky #visionscience #neuroskyence
Here is a short piece in the Conversation about the Spoon Illusion: doi.org/10.64628/AA....
#psychscisky #neuroskyence but not-really #visionscience
#psychscisky #neuroskyence but not-really #visionscience
Auditory illusions: new research discovers how our ears play tricks on us
Without visual clues, our ears mishear sounds produced in front of us. Knowing more about why this happens will give new insights into how the brain works.
doi.org
November 20, 2025 at 1:52 AM
Here is a short piece in the Conversation about the Spoon Illusion: doi.org/10.64628/AA....
#psychscisky #neuroskyence but not-really #visionscience
#psychscisky #neuroskyence but not-really #visionscience
Let me present the Spoon Illusion 🙂🥄
This has been in the works for over a decade when we were just goofing around testing sound localisation in my in-laws' kitchen... But we finally managed to do some reasonably controlled experiments on this. #psychscisky #neuroskyence
doi.org/10.1177/0301...
This has been in the works for over a decade when we were just goofing around testing sound localisation in my in-laws' kitchen... But we finally managed to do some reasonably controlled experiments on this. #psychscisky #neuroskyence
doi.org/10.1177/0301...
November 19, 2025 at 9:20 PM
Let me present the Spoon Illusion 🙂🥄
This has been in the works for over a decade when we were just goofing around testing sound localisation in my in-laws' kitchen... But we finally managed to do some reasonably controlled experiments on this. #psychscisky #neuroskyence
doi.org/10.1177/0301...
This has been in the works for over a decade when we were just goofing around testing sound localisation in my in-laws' kitchen... But we finally managed to do some reasonably controlled experiments on this. #psychscisky #neuroskyence
doi.org/10.1177/0301...
In this preprint, we concurrently fit the HRF alongside pRF parameters doi.org/10.1101/2025...
- HRF varies between visual areas
- HRF also varies with pRF stimulus designs (due to nonlinearities?)
- Esp. when fitting complex models this can skew results a lot!
#visionscience #neuroskyence
- HRF varies between visual areas
- HRF also varies with pRF stimulus designs (due to nonlinearities?)
- Esp. when fitting complex models this can skew results a lot!
#visionscience #neuroskyence
November 18, 2025 at 11:35 PM
In this preprint, we concurrently fit the HRF alongside pRF parameters doi.org/10.1101/2025...
- HRF varies between visual areas
- HRF also varies with pRF stimulus designs (due to nonlinearities?)
- Esp. when fitting complex models this can skew results a lot!
#visionscience #neuroskyence
- HRF varies between visual areas
- HRF also varies with pRF stimulus designs (due to nonlinearities?)
- Esp. when fitting complex models this can skew results a lot!
#visionscience #neuroskyence
The Ponizsa illusion - Kanizsa triangle produces Ponzo illusion, but oddly it inverts apparent depth: the longer line looks closer! Also has an inversion effect like we studied in Altan et al 2025 Proc Roy Soc (doi.org/10.1098/rspb...) but it's also in reverse! 🤔
#visionscience #psychscisky
#visionscience #psychscisky
November 12, 2025 at 2:58 AM
The Ponizsa illusion - Kanizsa triangle produces Ponzo illusion, but oddly it inverts apparent depth: the longer line looks closer! Also has an inversion effect like we studied in Altan et al 2025 Proc Roy Soc (doi.org/10.1098/rspb...) but it's also in reverse! 🤔
#visionscience #psychscisky
#visionscience #psychscisky
SAVE THE DATE! Australasian Society for Experimental Psychology (EPC) & Asia-Pacific Conference on Vision (APCV) Joint Meeting from 1-4 July at the University of Auckland, NZ.
#PsychSciSky #VisionScience #neuroskyence
More information to follow!
visualneuroscience.auckland.ac.nz/epc-apcv-2026/
#PsychSciSky #VisionScience #neuroskyence
More information to follow!
visualneuroscience.auckland.ac.nz/epc-apcv-2026/
October 20, 2025 at 8:54 PM
SAVE THE DATE! Australasian Society for Experimental Psychology (EPC) & Asia-Pacific Conference on Vision (APCV) Joint Meeting from 1-4 July at the University of Auckland, NZ.
#PsychSciSky #VisionScience #neuroskyence
More information to follow!
visualneuroscience.auckland.ac.nz/epc-apcv-2026/
#PsychSciSky #VisionScience #neuroskyence
More information to follow!
visualneuroscience.auckland.ac.nz/epc-apcv-2026/
This is exactly the problem inherent with so much #mentalimagery research: without any objective external reference to validate this, it is no better (& most likely worse...) than simply asking people how clear & detailed their imagery is. Because it is literally the same question in disguise.
Aphantasics often report N=0 or 1, Hyperphantasics can go 10+. This correlates with VVIQ, but N is an actual performance metric, not a feeling.
Bonus: As you do this, you might feel the urge to "pick up" and "eat" one of the nuggets. You might even "taste" it.
That's it. That's the whole point.
Bonus: As you do this, you might feel the urge to "pick up" and "eat" one of the nuggets. You might even "taste" it.
That's it. That's the whole point.
October 5, 2025 at 10:28 AM
This is exactly the problem inherent with so much #mentalimagery research: without any objective external reference to validate this, it is no better (& most likely worse...) than simply asking people how clear & detailed their imagery is. Because it is literally the same question in disguise.
No. As we argue in the paper this is exactly -not- the case. The VVIQ is surprisingly useful and I say this as a long time critic of this test. Perhaps it just correlates with a lot of self-reports of things people think happen inside their minds - but even if that's the case this is important...
This merely indicates that VVIQ is worthless— I suggested to consider the Rotating Chicken Nugget Test
The debate around imagery vividness (VVIQ) is stuck. We're using thermometers to measure GPU clocks.
Why? We're confusing attentional tracking (slow, costly) with parallel mental rendering (the truth of imagination's bandwidth).
#IPWT #CognitiveScience #Aphantasia
Why? We're confusing attentional tracking (slow, costly) with parallel mental rendering (the truth of imagination's bandwidth).
#IPWT #CognitiveScience #Aphantasia
October 5, 2025 at 9:57 AM
No. As we argue in the paper this is exactly -not- the case. The VVIQ is surprisingly useful and I say this as a long time critic of this test. Perhaps it just correlates with a lot of self-reports of things people think happen inside their minds - but even if that's the case this is important...
Long time in the making: our preprint of survey study on the diversity with how people seem to experience #mentalimagery. Suggests #aphantasia should be redefined as absence of depictive thought, not merely "not seeing". Some more take home msg:
#psychskysci #neuroscience
doi.org/10.1101/2025...
#psychskysci #neuroscience
doi.org/10.1101/2025...
October 2, 2025 at 6:10 PM
Long time in the making: our preprint of survey study on the diversity with how people seem to experience #mentalimagery. Suggests #aphantasia should be redefined as absence of depictive thought, not merely "not seeing". Some more take home msg:
#psychskysci #neuroscience
doi.org/10.1101/2025...
#psychskysci #neuroscience
doi.org/10.1101/2025...
Interesting piece on #aphantasia. But any conclusion about decoding #mentalimagery from aphants is confounded if we lump low-imagery people in with those who say they only have semantic representations. All 3 studies reviewed did exactly that. #PsychSciSky #neuroskyence
doi.org/10.1016/j.co...
doi.org/10.1016/j.co...
Redirecting
doi.org
October 1, 2025 at 3:26 AM
Interesting piece on #aphantasia. But any conclusion about decoding #mentalimagery from aphants is confounded if we lump low-imagery people in with those who say they only have semantic representations. All 3 studies reviewed did exactly that. #PsychSciSky #neuroskyence
doi.org/10.1016/j.co...
doi.org/10.1016/j.co...
Ecem Altan's excellent study showing that adaptation to spatial frequency modulates pRF estimates now published:
doi.org/10.7554/eLif...
I mostly enjoyed the novel review process - except that @elife.bsky.social apparently did not publish our final reply to reviewers😒
#visionscience #neuroskyence
doi.org/10.7554/eLif...
I mostly enjoyed the novel review process - except that @elife.bsky.social apparently did not publish our final reply to reviewers😒
#visionscience #neuroskyence
September 29, 2025 at 11:00 PM
Ecem Altan's excellent study showing that adaptation to spatial frequency modulates pRF estimates now published:
doi.org/10.7554/eLif...
I mostly enjoyed the novel review process - except that @elife.bsky.social apparently did not publish our final reply to reviewers😒
#visionscience #neuroskyence
doi.org/10.7554/eLif...
I mostly enjoyed the novel review process - except that @elife.bsky.social apparently did not publish our final reply to reviewers😒
#visionscience #neuroskyence
Reposted by Sam Schwarzkopf
Thanks to all (co)authors & reviewers for their contribution to this study on #layer specific changes in #sensory #cortex across the #lifespan in #humans & #mice now out in @natneuro.nature.com Here is a short summary of our findings 1/6
🧠 The human brain ages less than thought and in layers – at least in the area of the cortex responsible for the sense of touch. See study @natneuro.nature.com by @estherkuehn.bsky.social and colleagues at DZNE, @hih-tuebingen.bsky.social and @uni-magdeburg.de:
👉 www.nature.com/articles/s41...
👉 www.nature.com/articles/s41...
Layer-specific changes in sensory cortex across the lifespan in mice and humans - Nature Neuroscience
The principal layer architecture of the sensory cortex is altered with aging. The authors show that overall thinning of the primary somatosensory cortex is driven by deep layer degeneration but that l...
www.nature.com
August 11, 2025 at 2:29 PM
Reposted by Sam Schwarzkopf
New from Arnold @visnerd.bsky.social lab:
Mental rotation is often regarded as paradigmatic for #mentalimagery. But it turns out people often don't use imagery for mental rotation - & when they do it is often not useful (same viewpoint trials). #visionscience #psychscisky
doi.org/10.1016/j.co...
Mental rotation is often regarded as paradigmatic for #mentalimagery. But it turns out people often don't use imagery for mental rotation - & when they do it is often not useful (same viewpoint trials). #visionscience #psychscisky
doi.org/10.1016/j.co...
Redirecting
doi.org
July 21, 2025 at 12:20 AM
New from Arnold @visnerd.bsky.social lab:
Mental rotation is often regarded as paradigmatic for #mentalimagery. But it turns out people often don't use imagery for mental rotation - & when they do it is often not useful (same viewpoint trials). #visionscience #psychscisky
doi.org/10.1016/j.co...
Mental rotation is often regarded as paradigmatic for #mentalimagery. But it turns out people often don't use imagery for mental rotation - & when they do it is often not useful (same viewpoint trials). #visionscience #psychscisky
doi.org/10.1016/j.co...
Opinion piece now published as part of special issue in Neuropsychologia: #visionscience #neuroskyence #psychscisky #illusions doi.org/10.1016/j.ne...
Also, this happens to be my 100th publication. Join me for 🍺in OGH on Friday afternoon! 🙂
Also, this happens to be my 100th publication. Join me for 🍺in OGH on Friday afternoon! 🙂
July 9, 2025 at 1:34 AM
Opinion piece now published as part of special issue in Neuropsychologia: #visionscience #neuroskyence #psychscisky #illusions doi.org/10.1016/j.ne...
Also, this happens to be my 100th publication. Join me for 🍺in OGH on Friday afternoon! 🙂
Also, this happens to be my 100th publication. Join me for 🍺in OGH on Friday afternoon! 🙂
If you have 10-20 minutes (depends on how fast you are), would you please consider doing this online study on #mentalimagery? It contains a survey & an experiment where you look at pictures and you respond what you see:
#psychscisky #neuroskyence #visionscience
tstbl.co/820-917
#psychscisky #neuroskyence #visionscience
tstbl.co/820-917
July 7, 2025 at 1:51 AM
If you have 10-20 minutes (depends on how fast you are), would you please consider doing this online study on #mentalimagery? It contains a survey & an experiment where you look at pictures and you respond what you see:
#psychscisky #neuroskyence #visionscience
tstbl.co/820-917
#psychscisky #neuroskyence #visionscience
tstbl.co/820-917
Reposted by Sam Schwarzkopf
I spent an hour this morning procrastinating by writing this one pager "(One of My) Problems with the Science of Aphantasia"
osf.io/hr6w5/?view_...
osf.io/hr6w5/?view_...
(One of My) Problems with the Science of Aphantasia
Hosted on the Open Science Framework
osf.io
June 24, 2025 at 12:49 AM
I spent an hour this morning procrastinating by writing this one pager "(One of My) Problems with the Science of Aphantasia"
osf.io/hr6w5/?view_...
osf.io/hr6w5/?view_...
Another thing that only just occurred to me now: These questionnaire scores (VVIQ and MEQ) are supposedly transformed into percentages, but they have values >100...
Ahem... While on the topic of #aphantasia & #mentalimagery: This preprint reports correlations between questionnaires & some measure of hippocampal asymmetry that explain 90-100% of variance. Whenever I see data like this, I'd immediately suspect a bug in the code.
doi.org/10.31234/osf...
doi.org/10.31234/osf...
May 29, 2025 at 2:29 AM
Another thing that only just occurred to me now: These questionnaire scores (VVIQ and MEQ) are supposedly transformed into percentages, but they have values >100...
Ahem... While on the topic of #aphantasia & #mentalimagery: This preprint reports correlations between questionnaires & some measure of hippocampal asymmetry that explain 90-100% of variance. Whenever I see data like this, I'd immediately suspect a bug in the code.
doi.org/10.31234/osf...
doi.org/10.31234/osf...
May 27, 2025 at 3:35 AM
Ahem... While on the topic of #aphantasia & #mentalimagery: This preprint reports correlations between questionnaires & some measure of hippocampal asymmetry that explain 90-100% of variance. Whenever I see data like this, I'd immediately suspect a bug in the code.
doi.org/10.31234/osf...
doi.org/10.31234/osf...
I agree up to a point. Even with the "I literally see things before my eyes" responses we get in our survey I remain unsure if that's really what people mean.
Although I'd also say that the duck-rabbit -is- an experience in eyes, while my mental image is in my head. So not sure about any of it.
Although I'd also say that the duck-rabbit -is- an experience in eyes, while my mental image is in my head. So not sure about any of it.
New preprint tries to resolve this: osf.io/86c9r_v1 Mental images potentially involve the parts of experience that change when the rabbit-duck illusion flips, not the parts that remain stable. We often use "see" to refer to both parts: "I see a rabbit" vs "I see hues/shades", causing confusion.
May 27, 2025 at 12:43 AM
I agree up to a point. Even with the "I literally see things before my eyes" responses we get in our survey I remain unsure if that's really what people mean.
Although I'd also say that the duck-rabbit -is- an experience in eyes, while my mental image is in my head. So not sure about any of it.
Although I'd also say that the duck-rabbit -is- an experience in eyes, while my mental image is in my head. So not sure about any of it.
The problem with this design is that it isn't an objective test of perception (and in fact their other work on this shows that this is about criterion shifts). But objective tests of perception may fail because they ruin the whole experience (I know because I've tried - but we keep trying...)
The paper shows that imagery is "strong enough" to be indistinguishable from (weak) perception sometimes. In study 2, about half of participants were convinced they saw a stimulus when they were just imagining it. And these were "typical" imagers, not hyperphantasics.
May 27, 2025 at 12:33 AM
The problem with this design is that it isn't an objective test of perception (and in fact their other work on this shows that this is about criterion shifts). But objective tests of perception may fail because they ruin the whole experience (I know because I've tried - but we keep trying...)
🤣
Researcher: "Let's throw a ball on the weekend"
Participant 1: *brings a catchers mitt*
Participant 2: *brings a ballgown*
Participant 1: *brings a catchers mitt*
Participant 2: *brings a ballgown*
May 27, 2025 at 12:25 AM
🤣