The Australian Senate inquiry into micro-transactions heard a call for “serious consideration” to restrict games with loot boxes to “players of legal gambling age” earlier this week. The authors of a large scale study presented their findings, strongly supporting a previous study that claimed loot boxes were psychologically akin to gambling.

The study by Dr David Zendle and Paul Cairns from York St. John University and the University of York. Dr Zendle submitted that study to the Environment and Communications References Committee yesterday at a public hearing, and was the only person to appear in front of the committee.

Titled “Loot box spending in video games is linked to problem gambling severity”, the study surveyed 7,422 gamers through a paid online survey (over six thousand replies were discarded due to non-serious answers, incomplete answers or for ethical concerns).

The study took direct aim at the prevailing industry view of loot boxes:

Industry statements typically disassociate loot boxes from gambling. They instead highlight similarities between loot boxes and harmless products like trading cards or Kinder Surprise eggs. As the ESRC put it: “We do not consider loot boxes to be gambling … loot boxes are more comparable to baseball cards, where there is an element of surprise and you always get something.”

These results support the position of academics who claim that loot boxes are psychologically akin to gambling. Spending large amounts of money on loot boxes was associated with problematic levels of spending on other forms of gambling. This is what one would expect if loot boxes psychologically constituted a form of gambling. It is not what one would expect if loot boxes were, instead, psychologically comparable to baseball cards.

The submission also warned that their results suggest that either “loot boxes act as a gateway to problem gambling amongst gamers” or that loot boxes give developers “an unregulated way of exploiting gambling disorders amongst their customers”.

To that end, Dr Zendle and Cairns added to previous submissions calling for loot boxes to be earmarked in parental advisories, as well as a descriptor noting the presence of “in-game gambling content”. This would likely be done through the classification system.

“We recommend that … serious consideration is given to restricting games that contain loot boxes to players of legal gambling age,” the academics added.

The academics noted in the study that the relationship between loot box use and problem gambling was “stronger previously observed relationships between problem gambling and factors like alcohol abuse, drug use, and depression”.

They noted that the research was correlational, however, and that it was impossible to determine whether their results were looking at a situation where loot box spending would encourage problem gambling, or vice versa.

“It may, indeed be the case that both directions of causality are true: Problem gamblers spend more on loot boxes, whilst buying loot boxes simultaneously leads to increases in problem gambling amongst gamers,” they added.

Their submission, which includes the study, can be downloaded from the Australian Parliament website. The academics’ video submission to the inquiry can also be viewed here.

This story originally appeared on Kotaku Australia.