Google is currently working on Meena, a particular chatbot, which should be able to have arbitrary conversations and be used in many contexts. In their paper “Towards a Human-like Open-Domain Chatbot“, the developers present the 2.6 billion parameters end-to-end trained neural conversational model. They show that Meena “can conduct conversations that are more sensible and specific than existing state-of-the-art chatbots”. “Such improvements are reflected through a new human evaluation metric that we propose for open-domain chatbots, called Sensibleness and Specificity Average (SSA), which captures basic, but important attributes for human conversation. Remarkably, we demonstrate that perplexity, an automatic metric that is readily available to any neural conversational models, highly correlates with SSA.” (Google AI Blog) The company draws a comparison with OpenAI GPT-2, a model used in “Talk to Transformer” and Harmony, among others, which uses 1.5 billion parameters and is based on the text content of 8 million web pages.