Public perceptions of positive and negative heritage values: a social media analysis of Shanghai’s old concessions

Value integrity is a critical dimension in heritage practice, yet the conflicting nature of values may result in the categorisation of positive and negative values, with the latter being neglected or even erased. Shanghai’s old concessions have carried complex and conflicting historical backgrounds, while, through processes of preservation and management, they have become relatively positive urban spaces. This study examines public perception through a social media approach in this conflicted context. A total of 25,588 social media comments were categorised using a BERT-driven machine learning method, with further analysis considering the spatial, content and sentiment characteristics of different perceived value types. Key findings include: 1) Compared with well-perceived positive values, negative values are less perceived and often excluded from preservation efforts; 2) Positive values focus on historical context, design quality, and contemporary functions, while negative values relate to painful historical events and physical decay; 3) Negative heritage values evoke strong negative emotions, particularly in terms of social value; 4) Positive and negative values in some cases can reinforce each other. The paper calls for inclusive heritage discourse, offering a safe space for expressing negative values and emotions. We argue for preservation and regeneration strategies that recognise both positive and negative values, thereby contributing to a more complete understanding of heritage value integrity.