When did you last use the ATM and how much did you take out? Are you sure? A new study says our recall regarding cash machines and other financial matters is more often wrong than right.

Every day new banking studies come out and look at customer expectations and behavior in the new omnichannel banking world. Do customers like the branch or not? What features do they want in a mobile app and what features do they not use at all? This data is carefully studied by bankers and consultants and proclamations and predictions are issued as a result.

The trouble with this scenario is that customers don’t know what they want and have faulty memories. The problem of the irrational consumer is a common one for economists and now is making its way into studies of banking.

The analytics firm Sixxteps, based in Racine, Wisc. and Szeged, Hungary, recently concluded a study about irrationality in banking customers and a small portion of the findings was released Sunday, April 6. The goal of the study, which was limited to customers of one bank and so is far from comprehensive, was to “segment and scale the irrationality of [bank] customers.”

Among other findings, the study found that customers were wrong the majority of the time about their general ATM usage. This echoes research from Personetics that says customers don’t know how much they spend on ATM fees and therefore don’t take steps to correct the situation.

The study also found that the vast majority of customers had no idea about fees associated with wire transfers, which should surprise no one. More troubling than failing to understand wire transfers was customers’ failure to choose the optimal account based on their income, assets & liabilities, and accounts on offer.

In the short term, customers’ poor decisions may benefit banks — the paying of unnecessary fees is an obvious example — but in the long term, banks can expect to retain more customers that are happy and feel supported by the institutions. Bankers should hope for an increase in rationality in customer behavior regarding money. (Insurance companies may view the landscape of irrationality quiter differently.)

One hopeful sign, according to Sixxteps, is humans’ social natures. (Paging Phroogal.) As information that was once private is now entering the public sphere through social media and other means, perhaps, if we can’t save ourselves, our friends can help.