In today's world, our relationships with technology are becoming increasingly complex. It is no longer a case of smart items giving a responsive to one specific action - robots are learning how to interpret our facial expressions, read our body language and even react to our physiological responses - some of which are so small that we cannot detect them ourselves.

There is a whole world of exciting applications for these technologies: help with mindfulness meditation, conveying a feeling of connection to a partner while they're away, changing the ambience of a film to suit our current mood and even teaching children with autism spectrum disorders, who can struggle with conventional therapy.

However, despite great efforts and investments, emotive humanoid robot companions remain deeply uncanny, and elderly patients in Japan have rejected robotic care despite a critical shortage of human nurses. Ethically speaking, there are more complications - is it acceptable to allow elderly people to believe that the seal pup they so enjoy petting is real, when it is actually made of nuts and bolts covered in synthetic fur?

Employers are monitoring their workers' concentration and robot teachers can track and adapt to students' engagement with lessons. As emotional technologies pervade our belongings, buildings and infrastructure, how will our relationships with them evolve? And how should we be preparing to regulate these increasingly complicated and remarkable machines?

Gawain Morrison talks about his work measuring physiological responses

Brendan Walker on how the collection and use of physiological data can be applied to design

View our infographic on technology that responds to emotional signals