Despite the impressive successes of generation and dialogue systems, how to endow a text generation system with particular personality traits to deliver more personalized responses remains under-investigated. In this work, we look at how to generate personalized responses for questions on Reddit by utilizing personalized user profiles and posting histories. Specifically, we release an open-domain single-turn dialog dataset made up of 1.5M conversation pairs together with 300k profiles of users and related comments. We then propose a memory network to generate personalized responses in dialogue that utilizes a novel mechanism of splitting memories: one for user profile meta attributes and the other for user-generated information like comment histories. Experimental results show the quantitative and qualitative improvements of our simple split memory network model over the state-of-the-art response generation baselines. The dataset and code are available here. Building human-like conversational systems, in particular chit-chat agents, has been a longstanding goal in language technology communities. Unlike task-oriented dialog agents that focus on completing specific tasks (Wen et al., 2017; Eric et al., 2017; Lei et al., 2018; Lowe et al., 2015), chit-chat agents need to dynamically interact with people, understand the meaning of human conversations (Hovy and Yang, 2021), and thereby make better responses to improve user experience. Despite the recent successes on building chitchat agents using data-driven approaches (Ritter et al., 2011; Banchs and Li, 2012; Serban et al., 2016; Li et al., 2016c; Parthasarathi and Pineau, 2018), lack of a consistent personality is still one of the common issues. The main reason is that these  The work is mainly done when YW was a visiting student at Georgia Institute of Technology. Question: Where do you live and what is something you are doing today? Responses: A: I live in Mongolia and I will be making some good sandwiches today. B: Midwest America , I will be skyping my brothers and going to band practice today. Question: What's your "go to" when you're sad? Responses: A: I listen to horror stories for some reason. B: I love to read or listen to sad music . Respondent Profile: A: Gender: female; Favorites: sandwich ; Possessions: Russian class; Residence: Mongolia ; Asia ; B: Family: brothers ; Self-description: guitarist ; Favorite: fakebooks ; Residence: America ; Respondent Comment Histories: A: I often fall asleep while listening to horror stories . B: Listening to sad music , I know it adds fuel to fire but the flame will burn out quicker and you'll feel better soon. models are often trained over conversations spoken by different people, ignoring their personality (Li et al., 2016b; Wei et al., 2019; Zhang et al., 2018). As shown in Table 1, different people responded differently to the same input question due to their diverse background including basic personal information and attitudes towards different things. Thus, it becomes essential to incorporate personalization into the modeling and evaluation of response generation and eventually chit-chat agents. There have been several personality-related dialogue datasets built for evaluating models' performances in personalized conversations, such as PERSONA-CHAT dataset (Zhang et al., 2018) and Facebook's Reddit dataset (Mazare et al., 2018). The PERSONA-CHAT dataset was collected by intentionally assigning annotators to predefined personas described by a set of sentences instead of their real personality. Such artificially generated conversations cannot adequately represent respondents and their personalities which would lead to dataset bias problems. For example, an introvert annotator can hardly imitate the response of a person with sociable personas. Moreover, the number of personas covered by this corpus is limited. Today's social media platforms such as Reddit and Twitter provide us with good opportunities to build a large scale of collections of naturally occurring conversations (Xifra and Grau, 2010; De Choudhury and De, 2014; Schrading et al., 2015) and also make it possible to provide consistent personalities. For instance, Facebook's Reddit dataset represents each user by a set of sentences chosen from their comment histories heuristically. However, they also acknowledged that these persona sentences might not well represent a general trait of users due to the limitation of their heuristic rules for sentence retrieval (Mazare et al., 2018). In this work, we introduce a personalized Reddit dataset PER-CHAT , an open-domain response generation dataset consisting of 1.5M conversations and 300k users. PER-CHAT covers finer-grained personal information for users, including discrete user attributes such as gender, residence, self-description and favorites inferred based on users' self-reported messages on Reddit, and contextual information such as their comments (3). Based on PER-CHAT, we propose a simple generative split memory network to incorporate diverse personal information, with a novel mechanism of splitting memories: one memory representation for user meta attributes (e.g., profile) and the other for user activity information (e.g., comment histories), respectively (4). Experimental results show that our generative split memory network outperforms state-of-the-art response generation baselines both quantitatively and qualitatively (5). Personalized Generation Datasets Much attention has been paid to construct personalized dialog datasets. Built upon the bAbI dialog dataset, Joshi et al. (2017) extended it to include information such as gender, age and dietary preference. This domain-specific dataset was then used to train goal-oriented dialog models for several restaurant reservation tasks. There are also several dialog datasets that focus on chit-chat scenarios, such as PERSONA-CHAT dataset (Zhang et al., 2018), Reddit dataset (Al-Rfou et al., 2016), Twitter dataset (Li et al., 2016b) and PersonalDialog dataset (Zheng et al., 2020). PERSONA-CHAT ( PC ) dataset consists of 1k different personas, and annotators are asked to conduct conversations according to assigned personas. The Reddit dataset and Twitter dataset simply use user ID information without any specific user information to indicate personalization. The PersonalDialog dataset ( PD ) (Zheng et al., 2020), collected from a Chinese social media Weibo, contains three kinds of personality traits (gender, location, age) for each user. On the other hand, Mazare et al. (2018) introduced personalization from Reddit ( PCR ) by incorporating the persona of each user with a (randomly chosen) subset of his/her posting comments. Zhong et al. (2020) further extended their datasets with annotated empathy information ( PEC ). In this work, we combine those two different ways of gathering personalization signals of users, i.e., meta profile attributes and users' posting histories, and provide a more comprehensive, large scale personalized dataset derived from natural social conversations. Personalized Generation Models Current dialog models can be divided into ranking-based models and generation-based models. Ranking-based models (Al-Rfou et al., 2016; Mazare et al., 2018; Zhang et al., 2018) focus more on the task of response selection that is to pick the best response from a pool of random candidates. In contrast, generation-based models attempt to generate response directly from any given input questions. Under personalized dialog settings, Zhang et al. (2018) claimed that ranking-based models performed better than generative models on their personalized dataset, suggesting that building personalized generation models are more challenging. With the development of recent large scale social media data and the success of sequence to sequence framework (Serban et al., 2016; Shang et al., 2015; Sutskever et al., 2014), several personalized response generation models have been proposed, and we can only mention a few here due to space limits. Li et al. (2016b) introduced the Speaker Model and the Speaker-Addressee Model that encoded user-id information into an additional vector and fed it into the decoder to capture the identity of the speakers. Kottur et al. (2017) further extended these speaker models into multi-turn conversations. In addition to using user id to capture personal information, Zhang et al. (2018) proposed a profile memory network that utilizes a memory network for encoding persona sentences. To further utilize personal traits, Zheng et al. (2020) proposed an attention mechanism to incorporate these user-related attributes in the decoding stage. Recently, there are a few works using meta-learning and reinforcement learning to enhance mutual persona perception Madotto et al. (2019); Kim et al. (2020); Majumder et al. (2020). However, few models have taken into account different potential sources of personalization signals such as profile attributes and comments. Our work conducts persona-aware representation learning by combining these two sources. Note that our split memories architecture is similar to Joshi et al. (2017) , but differs in tasks and memorizing histories. In our work, we focused on memorizing relevant history comments instead of dialog histories in multi-turn chat settings. Evaluation Metrics Most response generation models utilize perplexity, BLEU (Papineni et al., 2002) and recently BERTScore (Zhang et al., 2019) and Moverscore (Zhao et al., 2019) for evaluation (Serban et al., 2016; Xing et al., 2018). For evaluating personalization, Zheng et al. (2020) proposed to measure the accuracy of predicting personality traits by firstly training classifiers for different personality traits such as gender and age. However, for certain trait categories such as hobbies and location, it is quite difficult to train a reliable classifier. In terms of evaluating persona consistency between generated sentences and given user comments, Madotto et al. proposed consistency score using NLI models pre-trained on Dialog NLI dataset (Welleck et al., 2019), which is a corpus based on Persona dataset, with NLI annotation between persona description sentences and dialogues utterance. In this paper, we introduce an automatic metric for evaluating persona consistency between user profiles and these generated sentences. This section describes how we construct an open-domain single-turn dialog dataset with personalization information from Reddit, together with dataset analysis 1 . Specifically, we used r/AskReddit 2 , one of the most active subreddits based on an online subreddit ranking system sorted by number of active users 3 . Users on r/AskReddit are encouraged to write clear and direct questions, and most posted questions are about open-ended discussion on a va-1 Similar process can be employed to our raw data to obtain MULTI-TURN dialog datasets. riety of topics, without definite or correct answers or professional knowledge, making r/AskReddit a suitable place to model personalization in open domain dialogue systems. Data Preprocessing. We collected all submissions under r/AskReddit as questions and their subsequent comments as responses. Each submission and one of its direct comment form a (question, response) pair in our corpus, i.e., single-turn dialogues. Furthermore, we stripped away potential markdown and Html syntax tokens and replaced all forms of url links, emails, and digits in our corpus with unique tokens url, email and digit respectively. We also processed replicated words and punctuation to their standard form via a set of regular expressions, e.g., coooool is converted into cool and !!!!! to !. Vocabulary and Conversation Pairs. We use a vocabulary of 50,257 entries the same as Dialogpt (Zhang et al., 2020), since they pretrained their models using the full Reddit data. To avoid lengthy questions or responses, we pruned the conversation pairs based on the statistics (see Figure 3 in Appendix A). Questions that exceed 100 words and responses with over 40 words are excluded. In total, there are 1,566,653 conversation pairs. To augment our dataset with personalization information, we collected three sources of user-related information: (1) user IDs which are unique user-names for their Reddit accounts; (2) comment histories , which are all the comments a user has posted on Reddit; (3) user profile attributes such as gender, residence, favorites and etc.. To collect these user-specific information, we first filtered out inactive users  a user who has made less than 100 comments during the recent year. There remain 301,243 users after removing inactive users. User Comment Histories. Users' comment histories can often signal their personal preferences toward topics or even texting habits as shown in Table 1, thus it is beneficial to collect these histories. We obtained a user's comment histories by querying the Pushshift Reddit API 4 . Since (1) it is infeasible for models to operate on the scale of thousands of comments and (2) applying persona extraction process rather than randomly picking up comments can improve model's performance 4 https://github.com/pushshift/api in personalization suggested by Mazare et al., we designed an information retrieval (IR) system to automatically pick up query-related comment histories for each user. Specifically, We utilized semantic embedding based similarity between each query and a comment to obtain a smaller set of candidates M , following similar retrieval mechanisms as Ritter et al. (2011); Wang et al. (2013). That is, given the input question, we retrieve top l comments that have the highest cosine similarity scores with the query to construct the user's comment histories. The embedding used in IR systems is the averaged contextual embeddings from pretrained BERT-large models(Devlin et al., 2019). Respondent Comment Histories of Table 1 shows some example query-related histories we extracted from a user's comments. User Profile. The persona extraction process to construct comment histories might lose valuable user's attributes such as their residence, favorites which are also helpful in generating personalized responses. To this end, we further conduct a finer-grained entity extraction mechanism over all of user's past histories. User profile information was viewed as entities extracted from histories using similar methods as the popular Reddit user analysis site SnoopSnoo 5 . Following the categories provided by the site, we first divided user attributes into eight types, including pets, family, resi-dence, favorites, partner, possessions, gen-der, self-description , where possessions refers to personal possessions owned by users such as users' guitars; favorites means users' favorite items and people mentioned by the user and self-description denotes concepts that users use to describe themselves such as their occupations. We then applied different extraction regular expressions for different categories. For example, we would gather a noun as favorites if it is found after  like,love,..  in certain comments. Examples for these attributes are shown in Respondent Profile of Table 1. Unlike some social media platforms such as Weibo, users on Reddit do not provide very specific profile information. Thus, we need to extract these entities based on their histories, and also check the reliability of such profile information. We manually checked whether such extracted user attributes actually corresponded to users' comments via a small corpus study (details 5 https://github.com/orionmelt/ snoopsnoo Number of Attributes 0.3% 4.6% 10.4% 16.1% 19.6% 20.3% 17.8% 10.9% 0 10 20 0-1 2 3 4 5 6 7 8 P e r c en t age ( % ) Figure 1: Distribution of users' number of attributes. in Appendix B), and found that in over 85% cases, our entity extracting process is quite reliable for capturing users' basic information. User Profile Analysis. We conducted in-depth analyses to show the coverage rate of each attribute out of the eight profile attributes in our collected corpus, as described in Table 2. We found that gender and possession have very high coverage rates above 99%, and other attributes have different coverage rates, ranging from 29.1% to 82.8%. Since it is unnecessary that users contain value under every attribute type, we also computed the percentage of users who have the corresponding number of attribute types. Figure 1 showed that most users have around 4 to 7 attributes. Question-Response Relevance To examine the quality of our constructed corpus, especially the question-response relevance, we randomly sampled 500 question-response pairs from our corpus, and asked for annotators from Amazon Mechanical Turk to rate them. Each pair is judged by three raters on whether a response appropriately responded to the given question. Raters can select from Yes', No', and Unsure' if they are unsure about the relevance. We obtained an intra-class correlation coefficient of 0.63 , indicating good IR System User comment histories: annotation agreement(Cicchetti, 1994). We categorized a pair as relevant if the majority of annotators vote Yes'. As summarized in Table 3, 86.8% of the pairs are found to be relevant, suggesting a reasonable quality of our corpus. Most questions in our corpus has around with 2 to 3 responses. We randomly sampled 1% of questions and their corresponding responses as the development set, 1% as the testing set, and the remaining 98% as the training set. Table 4 summarizes the detailed statistics. Comparisons with Related Datasets Table 5 shows the comparisons between our datasets and the related ones. The biggest advantage of our dataset is that it has both comment histories and user profiles while being 5-10 times bigger than any prior publicly available dataset. In our following experiments in section 5, we show the necessity to provide both dimensions of personalized information. In terms of comments, we applied pre-trained IR system to extract query related comments instead of simply rule-based filtering used in datasets such as PCR and PEC. In terms of user profiles, we provide more diverse categories with eight main types, larger than PD datasets which only contains age, gender and location. By utilizing social media data, our dataset allows for more diverse personality and natural dialog patterns with over 300k users than datasets collected by human (e.g. PC). This section presents our generative models for personalized response generation, which generate responses conditioned on given questions and respondents' personal information 6 . Let a conversation C be a tuple of Question, Response and respondent (User) C := ( Q, R, U ) . A user U = ( ID, P, M ) consists of three sources of information  username ( ID ), profile attributes P = ( f 1 , f 2 , . . . , f n ) , and user's comments M = ( m 1 , m 2 , . . . ) where f i is given as a key-value pair f i = < k i , v i > and M is a set of comment histories the user made. To better incorporate personal information of different dimensions, we propose a generative memory network with split memories for user profile and user comment history, respectively. The intuition lies in that interpersonal meta attributes and comment patterns may influence the respondents' responses differentially. The overall model architecture is shown in Figure 2. Our model is built 6 Multi-turn dialogue generation can be considered in our framework by encoding additional contexts in memories. upon a standard seq2seq model with attention. For a given conversation C , we first feed the input comments M through retrieval system to get query-related comment set M , and the memory network encoder computes the representations of related comment history. In parallel, profile attributes are added as separate profile memory by another encoder. At each time step, the decoder utilizes the aggregated representations of comment histories and profile attributes to generate the final response. For a user U with the profile P , we view P as the user's attribute sequence and employ a shared word embedding in encoder to encode the attribute key sequence as e k = ( e k 1 , e k 2 , ..., e k n ) and to encode each entry in attribute value sequence as e v = ( e v 1 , e v 2 , ..., e v n ) respectively. The final set of the user profile representation H p is defined as { e k 1 (cid:12) e v 1 , ..., e k n (cid:12) e v n } , which is considered as the profile memory. For encoding comment sentences, we encoded the retrieved comments M for a user U as individual memory representations in a memory network, similar to Zhang et al. (2018). Instead of applying weight functions to word vectors of each entry, we feed the comments to the RNN encoder to get the set of encoded history memories denoted as H m . We then pass H p and H m to a split memory encoder. The memory network separately attends to the encoded split memories with given query vector q over K hops as follows: a kp = Softmax (cid:16) H p  W 1  w kp (cid:17) (1) w k +1 p = ( a k p ) T  H p + w k p (2) a km = Softmax (cid:16) H m  W 2  w km (cid:17) (3) w k +1 m = ( a km ) T  H m + w km (4) where W 1 , W 2  R d  d and w 1 p = w 1 m = q . The outputs from both memories w Kp and w Km are summed to get the representation OK and is then fed into decoder side. The memory decoder utilizes the memory network and RNN. The RNN decoder takes as input the previous hidden state and previous target word embedding and generates the hidden state h t at the time step t . The vocabulary distribution P vocab for time step t is generated as follows: P vocab = Softmax ( W 3 [ h t ; OK ]) (5) where W 3  R | V | 2 d is a trainable parameter. Our implementation is based on the Pytorch version of OpenNMT (Klein et al., 2017) 7 . We used the pre-trained Dialogpt word embedding (Zhang et al., 2020). The hidden size of the encoder and decoder were set to 1024. The embedding size is the same as the memory size and the RNN hidden size. We used AdamW (Loshchilov and Hutter, 2018) as our optimizer with an initial learning rate of 5e-5 and a linear decay learning rate schedule. The dropout rate was set to 0.1. The batch size was selected in { 16 , 32 , 64 , 128 } . The maximum number of iteration steps was set as 20000 with an early stop if no improvement over perplexity on dev set. To generate hypothesis sentences, we used nucleus (top-p) filtering (Holtzman et al., 2019) without any re-scoring techniques. The cumulative probability for top-p filtering is set as 0.4. We introduced several baselines to compare with our generative split memory network ( GSMN ). Attention-Seq2Seq: a standard seq2seq model with attention mechanisms proposed by Luong et al. (2015), without utilizing any personal information. Speaker Model: Similar to (Li et al., 2016b), we employed an additional vector to model the respondent A . Generative Memory Network w/ History: Following Zhang et al. (2018), we encoded the retrieved comments as individual memory representation in a memory network to incorporate comment histories M . Dialogpt w/ Split Memories We directly combined the split memory network with the pretrained models , i.e. we applied the same architecture as GSMN in the decoder side and used pre-trained Dialogpt as the encoder. We evaluated the baselines and our generative split memory network using several widely-used metrics, including perplexity, BLEU, and BERTScore, to compare models' performances in generating appropriate responses. Perplexity is used to measure how the outputs fit test data (Vinyals and Le, 2015; Serban et al., 2016). Models with lower perplexity scores are found to demonstrate better performance to generate grammatical and fluent responses (Xie et al., 2019; Zheng et al., 2020). We also used BLEU (Papineni et al., 2002; Li et al., 2016a; Galley et al., 2015) with n -grams (n= 1 ) to measure how many n-grams in generated responses overlap with those in reference responses. To evaluate persona consistency between user comments and generated sentences, Madotto et al. proposed consistency C score using sequence classification model trained on Dialog NLI dataset (Welleck et al., 2019), a corpus based on Persona dataset, with NLI annotation. For given comments p j s and generated sentence u , the consistency score is given as follow: NLI ( u, p j ) =   1 if u entails p j 0 if u is independent to p j  1 if u contradicts p j C ( u ) = m (cid:88) j NLI ( u, p j ) (6) Note that models with higher consistency C scores tend to generate more persona consistent responses with user's comments. In our settings, m is set 10 for max number of given comments. PC-Score In addition to the aforementioned evaluation metrics, we also designed a metric called Profile Consistency Score ( PC-Score ) to measure a model's performance in generating persona consistent responses with given user profiles. The idea is similar to the entity score in knowledge enhanced conversation tasks (Zhou et al., 2018), which computes the number of entities for each response and aims to measure the model's ability to select the concepts from the commonsense knowledge. Instead of calculating the number of entities selected from knowledge base per response, we did a micro-average over the number of entities selected from the profile of each user to capture personalization. Manual Evaluation We conduct manual annotations to examine the consistency of those models. Here, the consistency refers to that the generated responses should be consistent for the same user when similar questions are asked. For example, when asked  Where are you from?  and  Where is your hometown? , the generated responses should be consistent in certain granularity for the same user. To this end, we randomly chose ten users from our user population set and designed 20 questions. Half of these questions are related to basic personal information, e.g., residence and gender, and the other half is related to personal interests and attitudes such as favorite activities. Detailed experiments are shown in the Appendix D. We generated 200 responses from each model, and asked annotators on Amazon Mechanical Turk to judge such consistency based on two criteria: (1) model consistency : whether or not a given generated sentence is consistent under the same group of questions; (2) personalization consistency : whether or not a given generated sentence is consistent with a user's personal information. Raters were asked to rate between 1 to 3 for model consistency, where 1 means  Not consistent at all , 2 means  Slightly Model User Information Consistency Personalization Consistency Attention-Seq2Seq 1 . 40  0 . 29  Speaker Model username 1 . 88  0 . 31  Generative Memory Network history 2 . 08  0 . 35  Generative Split Memory Network profile+history 2.29 0.43 Table 7: Manual evaluation results. Here, Personalization Consistency can take value from -1 to +1.  indicates significant difference with the best result (t-test, p-value < 0 . 05 ); and  : p < 0 . 01 . consistent , 3 means  Very consistent . For personalization consistency, raters rate whether the generated sentences match either the provided user profile attributes or user comments 8 . Note that when annotating personalization consistency, the turkers were not able to see the user ids; all the user information shown to them is publicly available on Reddit to protect user information. Table 6 summarizes different evaluation metrics on test set. We found that the Speaker Model boosted the Attention-Seq2Seq baseline with a decrease of 18 . 3 in perplexity, 3 . 14% increase in PC-Score, similar to Li et al. (2016b). However, because the user set is quite large, the performance improvement of Speaker model is limited. The generative memory network that incorporates either user profile or comment history demonstrates improvement compared with Attention-Seq2Seq in terms of all the metrics. Either generative memory network outperformed the speaker model, suggesting that network with additional user information has a better ability to generate semantic consistent and personalized responses. Furthermore, our proposed network ( GSMN ) significantly outperforms all other baselines, with a decrease of 38 . 7 in perplexity and a 28 . 4% increase in BLEU over Attention-Seq2Seq. By applying the split memories, Dialogpt w/ Split Memories further outperform Dialogpt in terms of all metrics. It shows that current pre-trained dialog models lack the ability of personalized memorization though they were found to be effective in memorization and generalization on a wide range of classical dialog tasks(Zhang et al. (2020)). This further justifies the necessity of our datasets. In terms of human evaluations for both consistency and personalization consistency (Table 7), our network also demonstrates consistent improvement over the baselines. Note that we do not apply 8 Comments that have highest similarity scores with the queries are used as references. any copy mechanisms in our models, the generation of personalized entities is purely depending on representation learning. It shows Split memory network outperforms the baselines on generating sentences with better personalization and consistency. To further examine the effectiveness of our generative split architecture, we also compared with Dialogpt that utilizes both profile and comment history to generating responses. In this setting, we included both profile and history as individual memory and did attention mechanism over this memory, shown as Dialogpt + profile + history . We observed that our generative split memory network still achieved better performance. Overall, this shows that incorporating both dimensions of personalization information, i.e., user profile and user comment history, can boost models' performances for response generation and split architecture for generation is better at utilizing these two different personalization signals. Diverse Responses Conditioned on Users: Table 12 in Appendix C shows some example responses generated by our GSMN, together with the Seq2Seq baseline. The examples are randomly sampled from our test set. Given different user profiles, GSMN is more effective and faithful to the profile attributes of different users in generating user-specific responses. For example, our model can identify user's profiles like families and gender when being asked about the most reliable person while the baseline's answer is more like consensus and applicable for any user. More examples are in Table 14 in Appendix C. Consistency Analysis: Example outputs from baselines and our model are described in Table 13 in Appendix C. The Seq2Seq model was a bit inconsistent in answering the same group of questions. The speaker model showed consistency to some degree since the answers California and Florida are quite close in the word embedding space, but failed due to the lack of user information. Compared with these baselines, GSMN is much better at generating both consistent and personalized responses. For example, when asked favorite activities, GSMN responds consistently and is also sensitive to personalized information since my dog identifies the pet attribute of the respondent. In this paper, we introduced a large-scale open-domain personalized dataset PER-CHAT and proposed a generative split memory network to utilize both user profile information and commenting histories for the task of response generation. Experimental results showed that our proposed model significantly outperformed several state-of-art baseline models, both quantitatively and qualitatively. Future research could build upon our work on single-turn response generation to further model personalization in multi-turn conversations. For the annotation, each worker on Amazon Mechanical Turk was paid 0.1$ per selection task (matching the United States federal minimum wage). To ensure quality, we chose only master crowd-workers who had more than 5000 HITs approved and with an approval rate larger than 95%. Considering the privacy violation problems our dataset may bring about, we followed Reddit's term of use for user contentbased on Reddit API Terms of Use, users are granted with license to display the user content through application 9 . We have taken careful procedures to protect users' privacy concerns. First, our introduced PER-CHAT dataset will be shared for academic use only . We only released raw data from pushshift.io(Baumgartner et al. (2020)), and open-sourced our scripts for preprocessing user attributes and models for reproducibility. Note that, the user attributes used in our work are identified based on users' self-reported statements via regular expressions matching. This research study has been approved by the Institutional Review Board (IRB) at the researchers' institution. Generation models trained on Reddit sometimes tend to generate toxic or inappropriate responses as pointed out by Dialogpt (Zhang et al., 2020). Due to this reason, we followed their best practices to deal with released version of decoding scripts 10 .
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