Mind Hacks

I’ve just found this surprising study in Psychological Science that found a link between the point in the menstrual cycle of 77 white women and various measures of race bias.

Race Bias Tracks Conception Risk Across the Menstrual Cycle.

Psychol Sci. 2009 May 4. [Epub ahead of print]

Navarrete CD, Fessler DM, Fleischman DS, Geyer J.

Although a considerable body of research explores alterations in women’s mating-relevant preferences across the menstrual cycle, investigators have yet to examine the potential for the menstrual cycle to influence intergroup attitudes. We examined the effects of changes in conception risk across the menstrual cycle on intergroup bias and found that increased conception risk was positively associated with several measures of race bias. This association was particularly strong when perceived vulnerability to sexual coercion was high. Our findings highlight the potential for hypotheses informed by an evolutionary perspective to generate new knowledge about current social problems-an avenue that may lead to new predictions in the study of intergroup relations.

The research paper is online as a pdf if you want the full details.

The authors explain the findings as suggesting that women show a preference to their ‘in group’, those who more closely match their own background and lifestyle, when most fertile.

Menstrual cycle has been found to influence numerous preferences in women in earlier studies, including dressing attractively, preference for the type of fanciable person, including a preference for more ‘masculine’ features.

Indeed, cycles in oestrogen are known to alter dopamine function in the striatum, a deep brain structure.

pdf of menstrual cycle and race bias study.
Link to PubMed entry for same.

Edge has an interesting article by neuroscientist David Eagleman on the perception of time that describes how we can experience temporal illusions just like we experience visual illusions.

I have to say, the piece is a little wordy, so it needs a bit of concentration, but it is well worth the effort.

This section has an interesting way of fooling ourselves into perceiving an event before you seem to have triggered it:

It has been shown that the brain constantly recalibrates its expectations about arrival times. And it does so by starting with a single, simple assumption: if it sends out a motor act (such as a clap of the hands), all the feedback should be assumed to be simultaneous and any delays should be adjusted until simultaneity is perceived.

In other words, the best way to predict the expected relative timing of incoming signals is to interact with the world: each time you kick or touch or knock on something, your brain makes the assumption that the sound, sight, and touch are simultaneous.

While this is a normally adaptive mechanism, we have discovered a strange consequence of it: Imagine that every time you press a key, you cause a brief flash of light. Now imagine we sneakily inject a tiny delay (say, two hundred milliseconds) between your key-press and the subsequent flash. You may not even be aware of the small, extra delay.

However, if we suddenly remove the delay, you will now believe that the flash occurred before your key-press, an illusory reversal of action and sensation. Your brain tells you this, of course, because it has adjusted to the timing of the delay.

If you’re wanting more on time perception, TED have just released an interesting lecture by Philip Zimbardo on how we reason about time.

And rather coincidentally, Eagleman is interviewed on ABC Radio National’s All in the Mind this week, about his synaesthesia research and fiction writing.

Link to Edge article on time perception.
Link to TED on reasoning about time (thanks Patricio!).
Link to AITM interview with David Eagleman.

I’ve discovered there is a small scientific literature on the cognitive science of belly dancing. Yes, I know I should be doing something else with my time, but it’s too late now and it’s too good not to share.

A group of movement researchers studied which fundamental action abilities were the best predictors of belly dancing skills in 1st-4th grade students and, in another study, in 5th and 6th grade students. Rhythmic coordination seems to be a key skill across most age groups.

Belly dancer’s myclonus is a condition where damage to the parts of the nervous system that control muscle coordination cause an involuntary stomach rippling effect that belly dancers strive to achieve. It is thought to be a problem with neural systems called ‘central pattern generators’ (CPGs) that create rhythmic pulses.

Jimmy Or is a robotics researcher who used what we know about the neuroscience of central pattern generators to create a belly dancing humanoid robot with a flexible spine. You can see it in action on his website.

I’ve just found this fascinating 2006 article by a consultant psychiatrist to the US Secret Service that classifies the types of stalkers and assassins that have troubled the President of the United States.

The piece, by psychiatry professor Robert Phillips, reviews past classifications of presidential harassers and cases from the literature to produce a list of main types.

In my work as consultant to the U.S. Secret Service on protective intelligence cases, it is my clinical assessment that aids in their ultimate determination of who poses a potential risk to a protectee.

In performing evaluations of persons who have either threatened or attacked presidents, pursued them without nefarious intent, or appeared at the White House without invitation, I have searched for a framework that would allow me to integrate my diagnostic opinion of an individual subject with a conceptualization of what is known about others who have acted similarly.

Phillips’ classification includes:

* The Resentful Presidential Stalker or Assassin
* The Pathologically Obsessed Presidential Stalker or Assassin
* The Presidential Infamy Seeker
* The Presidential Nuisance or Presidential Attention Seeker

But perhaps most interesting is the part where he illustrates each type with examples from past cases.

These include famous cases, such as John Hinckley – the man who shot President Reagan but was apparently also a stalker of Carter, to less well known cases such as one woman referred to only as ‘Ms Doe’ who “possessed a delusional love interest” in Clinton.

It’s interesting to compare this classification with the independently created typology of stalkers of the British royal family drawn from the Metropolitan Police’s Royalty Protection Unit files.

Link to full text of article.
Link to PubMed entry for same.

Not Exactly Rocket Science covers an intriguing study that provides further evidence for the theory that the brain treats tools as temporary body parts.

Using tools has lots of interesting effects on our perception. In one of my favourite studies, psychologist Dennis Proffitt found that we perceive distances as shorter when we have a tool in our hand, but only when we intend to use it.

This latest study found that using a tool for only a few minutes modified the body’s action settings. In the experiment, participants were asked to repeatedly pick up a block that had been placed in the middle of the table.

Then, they had to repeat the same actions with a grabber – a long, mechanical lever tipped with a two-fingered “hand” – and then a third time, with their own hand again.

Small LEDs on the volunteers’ hands allowed Cardinali to track their movements and calculate the speed and acceleration of their arms. She found that they reached for the block differently after they had been accustomed to the grabber, taking longer to accelerate their hands more slowly and to seize the block (although once they actually touched the blocks, they grasped them in just the same way as before). The delays even affected the speed at which they pointed at the block, a behaviour that wasn’t “trained” by the grabber.

To Cardinali, these results suggested that after using the grabber, the volunteers’ had included it into their mental representation of their own arms. Because of that, they felt that their arms were longer than they actually were and reached for the block more slowly.

Link to Not Exactly Rocket Science on tools as body extensions.