Eyes are well known to be incredibly powerful in guiding our behaviour.  For instance if you use a human face on a web page it's well known that browsers follow the gaze of the person in the photo.  This extends to the real world as well, as Stanley Milgram famously demonstrated when he got people to gaze skywards on a pavement.  When 3 people were looking to the heavens it persuaded dozens more to follow their gaze.

Magicians often take advantage of our weakness for following others gaze.  If they're doing a card trick they will often glance away, knowing that you'll follow their gaze and allow them to do their trick in your blind spot.

What's interesting however is that scientists have shown how arrows have the same effect.  The Italian research asked participants to look out for a target that was due to appear on screen, either on the left side or the right side.  Once they saw the target, they had to click the space bar.  Simple. 

To make it even easier they were given advanced warning of where the target would appear, with the word 'left' or 'right' appearing on the screen before the target appeared.

To spice things up a bit a follow up experiment added a face in between the word appearing and the target appearing.  The face would either be gazing in the direction of the target, or in the opposite direction.  Despite being told to ignore the face, it proved impossible.  When the eyes were looking in the opposite direction to the target, their reaction time was considerably slower, even if warned by the correct word beforehand.

What's interesting though is that the same slowing of reactions was seen if an arrow was used in place of a face.  It's as if the faces and arrows had irresistibly grabbed the participants' attention and sent it momentarily in the wrong direction.

"The finding that the information conveyed by distractors interfered with the task indicates that orienting of attention mediated by both gaze and arrows resists suppression and can be defined as strongly automatic," the researchers said.

Galfano's team added that the processes underlying the pulling power of gaze and arrows are not necessarily the same. The pull of another's gaze is apparent in the looking behaviour of new-born babies aged just two days, suggestive of an innate mechanism. The power of arrows, by contrast, is obviously based on learned symbolism.

So if you want people looking at your products or copy, using a persons gaze or an appropriately aligned arrow is the way to go.