Spooky science: Black cat bias and other Halloween oddities

October is Spring in the Southern Hemisphere. It’s also the month where you tend to find giant, out-of-season pumpkins cropping up in supermarkets. And instead of sprucing things up for an annual ‘spring clean’ an increasing number of households start decking their porches in spiderwebs.

In Australia, the spooky season is often considered a recent American import, even though the Mount Alexander Mail reports a Halloween Ball was held in Castlemaine as far back as 1858, an event which proved to be a great success “with couples dancing into the early hours of the morning.”

If we set aside misgivings about plastic costumes, fake blood and excessive amounts of sugar consumed by children awake well past their bedtimes, surely an evening spent trawling the neighbourhood with a fraid of ghosts, covens of witches, and mobs of zombies counts as some fairly harmless entertainment?

But amongst all the fun, occasionally it does seem our Halloween superstitions and suspicions can get a little out of hand.

Is it bad luck if a black cat crosses your path on Halloween?

‘Black Cat Bias’ refers to the phenomenon in which cats with black fur are perceived more negatively than their feline friends.

BCB is bad news for American cats. In the US, a study looking at the outcomes for nearly 8,000 cats in an animal shelter in Kentucky, found black cats were more likely to be euthanised and less likely to be adopted, than those with white fur.

And despite their connection to Halloween, black cats did not have an improved chance of adoption during the month of October. Nor do shelter bunnies at Easter, sadly.

A group of Texas psychologists set out to determine the root causes of BCB, testing four possible theories – was it religious beliefs, superstitions or even racism that led people to view black cats negatively? Or was it the difficulty in reading the emotions on their little cat faces?

The researchers asked 101 participants to rate cats on four measures: friendliness, aggressiveness, willingness to adopt, and how well they believed they could read the cat’s emotions. 20 cat photos were provided from nearby shelters in which all cats were depicted with a “neutral facial expression and pose”. Half of the cats were black and half in other colours.

Participants then completed three different questionnaires, the Santa Clara Strength of Religious Faith questionnaire (which assesses the role of faith in a person’s life), the Modern Racism scale (measuring racist attitudes) and the Revised Paranormal Belief Scale (testing belief in things like witchcraft and superstitions).

The study found evidence for black cat bias, with people rating the black-furred felines as less friendly, and more aggressive than the other cats, consistent across diverse participant backgrounds.

When combined with the results of the other questionnaires, the study suggested people with higher superstition scores were more likely than others to have unfavourable attitudes to black kitties.

It also indicated a link between people’s inability to read the emotions of a black cat, and negative scores on ‘friendliness’ and ‘aggressiveness’.

Australians seem to be less susceptible to black cat bias.

A study of the outcomes of 2,584 cats in a Sydney shelter (by the Sydney School of Veterinary Science) found black cats fared better with an overall shorter length of average stay than their white counterparts.

Perhaps concerns about white cats getting sunburn might be the reason behind this Southern Hemisphere effect, the paper suggested.

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Read more: Six spooky creatures to scare you this Halloween

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What about those urban myths about people tampering with trick-or-treat lollies, the razor or needle in the chocolate bar?

Fears about Halloween sadism – the idea that razor blades, needles, or metal objects might be hidden in Halloween treats – appear to have emerged sometime in the 1970s.

Incredibly, by the 1980s, American hospital emergency and radiology departments were regularly offering to x-ray Halloween lollies to allay people’s fears.

The x-raying of lolly bags has continued in some places despite studies finding no evidence that this sort of treat tampering was occurring, or even that x-raying lolly bags is an effective means of detection.

In 1988, a review of x-ray screening considered 1,063 x-rayed bags of lollies across 21 hospitals found no evidence of any metal objects buried in the sweets. The study estimated the US could be spending as much as $1.4 million of the public health purse on these x-rays.

A follow up study in 1992, involving 454 bags of lollies screened across five hospitals and three care centres, again found no evidence of tampering.

University of Delaware Sociologist Joel Best has been tracking and seeking to verify media reports of sabotaged sweets since 1985. Best updates his work regularly, and says in all the decades of his research, he has been unable to find a substantiated report of a child being killed or seriously injured by a contaminated treat collected during trick-or-treating.

The real risks of Halloween: traffic accidents and too much junk food

Analysis of accident data in the United States and the United Kingdom shows evidence for increased risk of traffic accidents resulting in pedestrian fatalities or serious injuries on Halloween, with the highest relative risk among children.

It makes sense if you think about it … groups of children and adults wandering the streets at dusk, behaving unpredictably, many with their vision obscured by costumes and masks.

There’s another public health risk according to Australia’s Nossal Institute for Global Health. In 2013 the institute warned against increased confectionary advertising targeting children in October.

“Each year, an increasing number of witches and wizards darken the doors of Australian households demanding free junk food,” their report says.

The authors suggested Australians stick to celebrating Halloween with more healthy options such as pumpkins, fruit or toys.

Would viewing a picture of Michelle Obama cause you to choose a healthier treat?

In a multi-year randomised control trial, involving 1,223 trick-or-treaters in New Haven, an economist from the Kellogg School of Management and two political scientists from Yale sought to determine whether trick-or-treaters who saw a picture of Michelle Obama’s face might be more likely to choose fruit over chocolate.

The experiment was conducted over three Halloweens in the East Rock neighbourhood of New Haven, Connecticut. Children who happened to be out trick or treating became part of the experiment and were randomly assigned to one or the other side of the porch.

Those children who did not wish to wait in line (perhaps, the paper remarks “due to an objective of maximising their candy per hour productivity rate”) did not approach the house and were not included.

One side of the porch, children were faced with a large photo of Michelle Obama.

On the other side, as a control or comparison, they included an alternative photo or no photo. In 2014 and 2015, the control photo was Hillary Clinton.

At both sides of the porch, children were asked their age and whether they would prefer to receive fruit (a box of raisins) or a small, packaged chocolate bar.

A marginally higher share of children (28%) on the Michelle Obama side chose raisins, compared to 23.5% who saw a picture of Clinton, Ann Romney or nothing.

The authors noted there were several limitations to their approach. Key drawbacks included running the experiment on a day where lollies were readily available, and when children might be under the influence of sugar consumption.

In other words … Halloween!