When is knowledge power? When is ignorance bliss?

Would you lie to a loved one about their terminal condition, to ensure their last few months or years were as happy as possible? Professor Cass Sunstein (Harvard University) lived through this reality – after his father was diagnosed with a terminal brain tumour, his mother kept this from her husband.

When involved with the Obama administration, Sunstein was a part of a group working on the inclusion of calorie data on food products – he was in favour of this information being included at cinemas. When he told his friend, the reply was, 'Cass ruined popcorn'. 

In a world where information is so freely available, he said, these examples raise a question: how do we decide whether knowledge is power or ignorance is bliss? Sunstein set out to ask people whether or not they would like to know certain things – calories in their meals (43 per cent would), the year of their death (27 per cent would), whether they'd develop Alzheimer's (around 47 per cent would). Sunstein gathered this data with no hypothesis – he was just curious – and started to ask what explains this need to gain or avoid information. 

He suggested that some information is simply useful. The calorie content of food, for example, can help us to make healthier choices. Sunstein calls this instrumental value. Some information may have neutral value or negative value. Some information may have hedonic or emotional value – for example in Sunstein's example of his father's brain tumour, the knowledge of this would have brought about certain emotions for him. 

Sunstein said we may wish to know some things even if they hold no value. He said we can think of this as cognitive value, for example knowing whether dogs are descended from wolves. Sunstein suggested that when people seek or avoid information they are making a judgement about the information's instrumental, cognitive and emotional value. 'This drives a lot of baffling results in the real world, where people don't want information that, let's say, questions their own political beliefs, or which suggests their investment portfolio is heading south.'

Another aspect to consider from psychology and behavioural economics, is that people are biased in their behaviour in predictable ways, and those biases may affect information seeking or avoidance. For example, humans are unrealistically optimistic, which can cause us to avoid important information. We also focus on the present rather than the past or future, and have an availability bias – we remember salient and familiar incidents better.

Sunstein said he is not a mental health professional, but information seeking or avoidance could be associated with mental illness – or at least sub-clinical levels of distress. 'This is meant to be suggestive rather than demonstrative. Some people who suffer from depression avoid information a lot, and their avoidance of information can be associated with the perpetuation of depression.

'You can have a very bad spiral in which information wasn't sought, then the depression continues or perhaps is deepened by the absence of information, which continues information avoidance, and it's a spiral that has to be broken in one way or another.' 

Sunstein hopes we will learn more about when it is accurate to say that knowledge is power and ignorance is bliss. 'I want to honour the human desire not to be terrified or distressed by information disclosure… not by withholding information from people who desire it, not ever by lying… but instead by being attuned, in a way that is gentle and kind, to the possible adverse effects of telling people things they really don't want to know.'

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