Science and facts aren't enough to wash away long-held beliefs.

I’VE never understood the dishwasher. It’s a large, electricity-guzzling machine that sits in the corner, taking hours instead of minutes to wash dishes that could otherwise be cleaned by hand. And in this era of water shortages and conservation, surely it’s not a good idea to get one.

Yet I was told that the reverse is true: dishwashers use less water, not more. This was a surprising fact to me.

An Internet search led me to a study conducted at Germany’s Bonn University, where 113 people were asked to wash dishes and their performance evaluated and compared with two dishwashers. The results? Dishwashers use significantly less water, resulting in dishes as clean or cleaner than human-washed ones. Although the dishwashers took longer to wash, most of it was done automatically.

My misgivings about the dishwasher is misplaced, and it seems to be better for the environment overall. Yet, I’m not exactly rushing out to buy one straight away, because – well, because it just doesn’t feel right.

It isn’t the first time we get opposing answers to the same question. For example, it happened recently with, “Does chocolate sold on our supermarket shelves contain pig DNA?”

You know the story: A rumour broke on social media recently that chocolates sold in Malaysia contained porcine DNA. Somewhere along the way, a Health Ministry test result was leaked suggesting one of Cadbury’s products had tested positive for the presence of porcine DNA. The ministry confirmed the result was genuine, leading to an uproar. A group of Muslim NGOs held a press conference ( that denounced the manufacturer, saying that “They have betrayed us Muslims by putting haram elements through the foods we consume in our body”, later adding, “We need to unite, we must declare jihad!”

Then Jakim (the department of Islamic Development Malaysia) conducted its own tests and made the announcement that no pig DNA was found in the samples they tested. Although this has calmed the situation down a little, the feeling of resentment still lingers. The NGOs concerned have lodged a report about the conflicting results, although I seriously doubt confusion is a crime.

What I found interesting was that there was very little discussion from a scientific perspective. How are such tests conducted and what does a positive result mean?

A little bit of background knowledge would have gone a long way towards understanding the context of the results. It’s unclear which method was used by the ministry and Jakim, but a quick search on the Internet reveals three products to detect porcine DNA, all using the PCR or qPCR method.

One advantage of the PCR method is that it can detect very small amounts of the sequences of DNA you are looking for. It does this by making many copies of the relevant sequence, so instead of looking for one copy, there are now millions, making detection easier. Obviously, the disadvantage is that it is also very sensitive to contamination – one product claimed 5 picograms would be enough to give a positive result (roughly, about a speck of dust) – so it is probably wise to run the test several times if we are going to validate a finding.

There’s also a difference depending on the source you are testing for. Jakim confirmed their samples came from the manufacturer, but it would be interesting for them to also test the sample the Health Ministry used, as well as another bar from the same reseller.

But all this was forgotten in the heat of the debate. I find it strange, because we are relying on the tests to give us information, so I would have thought how the testing is done and what the results really mean would be relevant to the case.

The objectivity of science is important, because too often, human conclusions on contentious issues are led by emotions and feeling, rooted in long-held beliefs. As an example, a study from the University of Western Australia asked students to read a report about a robbery. In the report, the race of the perpetrator was mentioned, but for some, the reported race was then retracted as a mistake.

The participants were then asked about the report. Although many could remember the details of the crime, those who were most prejudiced against Aborigines continued to identify them as the perpetrators, even when they could accurately remember that a retraction had been made.

It’s as if the facts don’t matter when they don’t fit your beliefs. For some, it is not surprising that a large foreign company doesn’t care about the well-being of Muslims, even if there is no evidence to support it.

When I think hard about it, I realise my feelings about washing dishes probably come from two sources. One, is that I only began to wash dishes when I started living on my own. It may subconsciously symbolise independence to me. Secondly, the only time I’ve regularly used a dishwasher is when I worked in a restaurant. That industrial grade machine regularly scalded me with hot water and strong alkalis – not a pleasant experience at all.

On top of everything else, I think I worry that if you don’t do things for yourself, you may be over-dependent on technology to run your life. (At least give me credit of recognising the irony of typing the previous sentence on a computer.)

In fact, I find washing dishes quite meditative and therapeutic, an oasis of calm between dinner and bedtime. I suppose that doesn’t have to disappear just because one uses the dishwasher, although I would have to contend with the irrationality that I may be washing dishes that are already clean.

Mathematician-turned-scriptwriter Dzof’s theory is that people need both logic and emotion to make sense
of life’s vagaries and contradictions. Write to him at