''[People] are no longer comfortable in expressing racism directly,'' White says. ''Instead, they might advocate laws and policies that disadvantage racial minorities. For example, [they might think]: 'It's not that I have a problem with racial minorities, I just don't like the welfare system.''' Although overt racist behaviour is now taboo - and racial discrimination quite illegal in many parts of the world - scientists claim that harbouring implicit racist attitudes is commonplace behaviour. Modern-day social pressures may have driven ''traditional'' forms of racism underground, particularly in Western nations, but that does not mean racism is dead. And, according to research, it may be because we tolerate racism more than we think. In a 2009 study by York University in Toronto, Professor Kerry Kawakami and her team found that participants - despite believing they would be upset and speak out against racism - were likely to remain indifferent or less upset when personally witnessing racist behaviour against a black person. Moreover, they were likely to pass off the racist comments as being a joke or in good humour. ''People often make inaccurate forecasts about how they would respond emotionally to negative events,'' University of British Columbia professor and study co-author Elizabeth Dunn says in an article in ScienceDaily. ''They vastly overestimate how upset they would feel in bad situations such as hearing a racial slur. ''One of the ways people may stem the tide of negative emotions related to witnessing a racial slur is to reconstrue the comment as a joke or as a harmless remark.''

In 1986, social psychology professors John Dovidio of Yale University and Sam Gaertner of the University of Delaware put forward the theory of ''aversive racism'', which held that because explicit racism was frowned upon, people had become averse to racism and could not admit to themselves when they held racist attitudes. This differed from ''old-fashioned racism'', which is characterised by overt hatred for and discrimination against racial/ethnic minorities. ''I think that this [aversive racism] is particularly important in some cultures, like in Australia or the United States, where we have strong societal pressures now not to look discriminatory or prejudiced,'' says social neuroscientist and psychologist at the University of Queensland Dr Eric Vanman. ''So [instead] we have these things internalised: 'I better be a good person and not say this joke or make a comment, even though I may be feeling something [negative].''' Naturally, we will never know what someone is thinking or what their racist beliefs are. But what Vanman has discovered is that the brain and body are very good at indicating the presence of implicit racist attitudes. For starters, holding racial prejudice inhibits cognitive ability. In a classic Dartmouth University study, researchers found that the more prejudice someone had, the more their brain worked to inhibit offensive behaviour when they interacted with other races.

Those with more racial bias had greater activity in their prefrontal lobes, the area of the brain in charge of decision-making, controlled behaviour and other cognitive processes. When it was time for them to complete a cognitive test, their prefrontal region had worked so hard to control any offensive behaviour, they ended up performing poorly. Even a brief encounter with a black person significantly affected the test performance of some of the white participants. It's just one of many examples that leave researchers asking why race affects behaviour in the first place. According to Vanman, the answer is partly physiological. ''There are specific regions of the brain that are involved in categorising people as in-group and out-group members automatically,'' he says. These ''regions'' are the brain's fusiform face area, as it is involved in face recognition and group categorisation. Vanman says that being part of a group - such as a sports team, office department, ethnicity or race - means you will automatically and unconsciously prefer those belonging to your ''in-group''. The opposite phenomenon happens to out-group members; you simply prefer not to associate with them. In fact, connect electrodes to the faces of Caucasians, African-Americans or Chinese Australians - as Vanman has done - and a peculiar thing happens. They smile (albeit it is undetectable to the naked eye) when they see pictures of people from their own racial group. But present profile photos of other races and the same participants will involuntarily frown. The fusiform face area also gets activated - regardless of the participant's race - so in-group bias seems to be a universal and automatic phenomenon, he says. ''That might just be part of the basic process; that as soon as you run into someone, you automatically notice their race, their gender and their age - and it happens so quickly, you can't even turn it off.''

This ''preference recognition'' appears to have evolved as a defence mechanism so outsiders who may be a threat to groups in prehistoric times were quickly identified. Our response to people from different races is also a cultural response. ''All people stereotype,'' White says. ''Stereotyping is a normal cognitive process that allows us to efficiently categorise things into groups … for example, 'Australians are sporty'. We learn these associations from birth via our parents, siblings, peers, teachers and the media. We are bombarded with stereotypes to the extent that they become automatic, to a certain degree. ''Stereotypes become problematic when people begin to endorse certain negative associations and allow these negative associations to affect their behaviour towards certain groups - this is when racism results.'' Fear has a part to play in reinforcing these negative associations. Studies have shown that when dealing with out-groups, the other area most commonly activated in the brain is the amygdala - the region involved with emotions and fear. ''You might have some fear of an out-group because of stereotypes or past experiences with them,'' Vanman says. ''It doesn't necessarily happen to every out-group member but it seems to happen with a lot of groups that you often hear bad things about in the press.''

Scientific research, Vanman says, has long established that it is quicker for highly prejudiced people to implicitly associate photos of African-Americans or Muslims with negative words than positive words. But while we inherently stereotype and classify people, there are effective ways to combat these negative associations that can lead to racism. Loading ''Clearly, we need to begin at home and parents of all cultures need to teach their children cultural inclusion and co-operation,'' White says. ''They have to encourage their children to interact in a positive way with different cultural groups. Through positive cultural interactions, children learn to see their friends from different cultures as individuals and the group categorisation mentality that [says] 'all people from that culture are the same' disappears - and with it, racism.'' For example, in one of White's studies, Caucasian-Australian teens with Asian-Australian friends had significantly lower levels of implicit and blatant prejudice towards Asians than those who didn't. ''With regard to racism,'' she says, ''Australia has come a long way in a positive sense but there is still much work ahead.''