If you're looking for the love of your life on online dating sites it may pay to take your time rather than rapidly swiping through profile pictures and making snap judgments about their attractiveness, new research suggests.

Key points: Our visual system is influenced by the immediate past

Our visual system is influenced by the immediate past Previous images can influence your view of current images

Previous images can influence your view of current images Snap judgments about attractiveness might mean you make the wrong decision.

That's because our visual system is influenced by the immediate past, say researchers, who have studied a system mimicking that used on smartphone apps like Tinder and Hot or Not, which allow users to swipe right on pictures rated as attractive, or left on those rated as unattractive.

"Your judgment is systematically influenced by the previous profile picture that you were looking at," University of Sydney neuroscientist Dr Jessica Taubert said.

"You're less likely to swipe right when the previous person was unattractive or ugly."

In a new study published today in Scientific Reports, Dr Taubert and her colleagues reported on two experiments in which female participants were asked to view 60 profile pictures of men taken from an online dating site.

Each profile picture was displayed repeatedly but randomly in a sequence, and only for 300 milliseconds.

The female participants had to make a rapid judgment about whether the face was attractive, in which case they pressed a right hand arrow key, or unattractive, in which case they pressed a left hand arrow key.

In between each profile picture, an image of a white cross appeared until the participant made their choice, which was typically complete within a fraction of a second.

Past images influence what we see in the present

The researchers found the first evidence of what scientists call "sequential dependence", in which the immediate past influences what we see in the present.

"If the participants rated the previous profile picture as attractive then they were more likely to see the current profile picture as attractive," Dr Taubert said.

"And if the previous picture was rated as unattractive then they were much more likely to perceive the current image as unattractive."

In keeping with this effect, the researchers found that the same profile picture could be rated as attractive or unattractive depending on where it appeared in the random sequence.

In some cases they found the image before the previous one, or even two before the previous one, could also influence the judgment.

Visual system limit to how much it can process

Dr Taubert said while some might think their rapid judgements are an efficient process, our visual system has a limit to how much it can process and this means our final choice can be at least "one face too late".

Preliminary evidence suggests the faster people get at swiping the more influenced they will be by previous images, she added.

"My best advice is to take your time with these tasks and maybe give yourself a big break in between each face just so your visual system has a chance to update itself and not be influenced by what it just saw," Dr Taubert said.

"I personally would take at least 20 seconds."

That may not sound like a long time, but it can be an eternity compared to the speed at which people tend to swipe left and right on a stream of images on their smart phones.