For each kind of question, a unique pattern must be available in the database to provide a suitable response. With lots of combination on patterns, it creates a hierarchical structure. We use algorithms to reduce the classifiers and generate the more manageable structure. Computer scientists call it a “Reductionist” approach- in order to give a simplified solution, it reduces the problem.

Artificial neural networks, invented in the 1940’s, are a way of calculating an output from an input (a classification) using weighted connections (“synapses”) that are calculated from repeated iterations through training data. Each pass through the training data alters the weights such that the neural network produces the output with greater “accuracy” (lower error rate).
Unlike Tay, Xiaoice remembers little bits of conversation, like a breakup with a boyfriend, and will ask you how you're feeling about it. Now, millions of young teens are texting her every day to help cheer them up and unburden their feelings — and Xiaoice remembers just enough to help keep the conversation going. Young Chinese people are spending hours chatting with Xiaoice, even telling the bot "I love you".
Back in April, National Geographic launched a Facebook Messenger bot to promote their new show about the theoretical physicist's work and personal life. Developed by 360i, the charismatic Einstein bot reintroduced audiences to the scientific figure in a more intimate setting, inviting them to learn about the lesser-known aspects of his life through a friendly, natural conversation with the man himself.
Chatbots could be used as weapons on the social networks such as Twitter or Facebook. An entity or individuals could design create a countless number of chatbots to harass people. They could even try to track how successful their harassment is by using machine-learning-based methods to sharpen their strategies and counteract harassment detection tools.
The NLP system has a wide and varied lexicon to better understand the complexities of natural language. Using an algorithmic process, it determines what has been asked and uses decision trees or slot-based algorithms that go through a predefined conversation path. After it understands the question, the computer then finds the best answer and provides it in the natural language of the user.

“It’s hard to balance that urge to just dogpile the latest thing when you’re feeling like there’s a land grab or gold rush about to happen all around you and that you might get left behind. But in the end quality wins out. Everyone will be better off if there’s laser focus on building great bot products that are meaningfully differentiated.” — Ryan Block, Cofounder of
Some bots communicate with other users of Internet-based services, via instant messaging (IM), Internet Relay Chat (IRC), or another web interface such as Facebook Bots and Twitterbots. These chatterbots may allow people to ask questions in plain English and then formulate a proper response. These bots can often handle many tasks, including reporting weather, zip-code information, sports scores, converting currency or other units, etc.[citation needed] Others are used for entertainment, such as SmarterChild on AOL Instant Messenger and MSN Messenger.

Three main reasons are often cited for this reluctance: the first is the human side—they think users will be reluctant to engage with a bot. The other two have more to do with bots’ expected performance: there is skepticism that bots will be able to appropriately incorporate history and context to create personalized experiences and believe they won’t be able to adequately understand human input.

Jabberwacky learns new responses and context based on real-time user interactions, rather than being driven from a static database. Some more recent chatbots also combine real-time learning with evolutionary algorithms that optimise their ability to communicate based on each conversation held. Still, there is currently no general purpose conversational artificial intelligence, and some software developers focus on the practical aspect, information retrieval.