Demonstrating that image training lowers text perplexity remains extremely difficult
Mostafa Dehghani · AI is Already Building AI — Google DeepMind’s Mostafa Dehghani · Apr 2, 2026 · at 48:54
Mostafa Dehghani, AI researcher at Google DeepMind, explains the technical challenge of achieving positive capability transfer across modalities during Gemini training.
0:00 / 0:25exact quote · 25.9s
▶ Watch the full episode on YouTube → 720p mp4 · rendered on demand · StarZero watermark
“So it turned out to be a really, really good model, but it was like really hard to see that. Wow. You know, I train on images and then like Text perplexity goes down. That was hard to see. You know, like the fact that, you know, you train in native model and it's good at, like across all the capabilities is already impressive. But my hope is that, you know, multimodality and model is the way to really push multimodal training to enable like positive transfer across modality.”
quote is from the automated transcript, cleaned for reading: filler sounds and stutters are removed, nothing is rephrased. names can be misheard (the analysis reads context, assessments check outside sources). how →
More from Mostafa Dehghani
New pre-training techniques will drastically boost base AI model capabilities
“The way that we used to do pre-training, maybe, like, you know, like two, a year ago or two years ago maybe, like, you know, diminishing return is, like, obvious, but I can see how new ideas are bringing, like, you know, fresh, fresh energy into the pre-traini…”
Fully automated AI self-improvement will eliminate human bottlenecks and trigger breakthroughs
“The moment that we had this full automation, I would say we can close the loop of self-improvement and then it becomes the Like, you know, the problems become like, you know, mostly providing compute for these models to actually do what they want to do. And as…”
AI model progress will alternate between pre-training and post-training breakthroughs
“We're going to be having a bit of a swing back and forth between pre-training and post-training.”
Post-training techniques cannot compensate for a weak base AI model
“Pre-training is still the foundation and like, you can never post-train your way out of a week-based model.”
Video data conveys physical world knowledge to AI more efficiently than text
“So because of that, like picking up a lot of knowledge about the word through language is just not really efficient. I don't want to say that it's impossible, but it's not efficient, you know, like to learn about gravity. If you kind of like, you know, have yo…”
Jagged intelligence in AI is a structural flaw, not a patchable bug
“Not easy to pinpoint like specific things, but again, like, you know, this is just like my personal opinion and maybe I have colleagues and like the other people like sharing this with me, but I think we're underestimating how hard like jagged intelligence is …”