Investors are not rational beings

For many economists, the fact that people aren’t 100% clear-minded, analytical and rational is a bizarrely new thought, says Merryn Somerset Webb.

We aren't rational. We like to think we are, but it just isn't so. Instead, we treasure things we have already to the extent that we'll demand people pay us more for our own goods than we would pay for them in the first place (the endowment effect). We experience the pain of financial loss more strongly than the joy of financial gain (loss aversion). We rate new information more highly than old and don't notice how much that skews our judgement (recency bias) and we just hate change (status quo bias).

That you aren't 100% clear-minded, analytical and rational might come as no surprise to most of you. But to many economists it is a bizarrely new thought and one for which Richard Thaler has just been awarded the 79thNobel Prize in Economic Sciences. This is shocking in one sense: how can the economics profession have got itself into such a formulaic rut that having the common sense to point out that people react to more than one influence at a time became an insight so radical that it is worthy of a Nobel prize? But the fact that behavioural science is gaining ground in economics is also encouraging.

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Merryn Somerset Webb

Merryn Somerset Webb started her career in Tokyo at public broadcaster NHK before becoming a Japanese equity broker at what was then Warburgs. She went on to work at SBC and UBS without moving from her desk in Kamiyacho (it was the age of mergers).

After five years in Japan she returned to work in the UK at Paribas. This soon became BNP Paribas. Again, no desk move was required. On leaving the City, Merryn helped The Week magazine with its City pages before becoming the launch editor of MoneyWeek in 2000 and taking on columns first in the Sunday Times and then in 2009 in the Financial Times

Twenty years on, MoneyWeek is the best-selling financial magazine in the UK. Merryn was its Editor in Chief until 2022. She is now a senior columnist at Bloomberg and host of the Merryn Talks Money podcast -  but still writes for Moneyweek monthly. 

Merryn is also is a non executive director of two investment trusts – BlackRock Throgmorton, and the Murray Income Investment Trust.