Spatial Bias Test: Results

East-West Confusion

How you map a problem in your head, may affect your brain's performance.

In theory, differentiating between each cardinal coordinate should be equally difficult.  To be asked “is X East of Y?” should be no more difficult than asking “is X North of Y?”.  North, South, East, West are man-made labels and are arbitrarily located.  North happens to be on the top of most maps, but there’s no reason it couldn’t equally be located on the right, left, or bottom.  Contrary to this logic, it appears that most people are worse with tasks differentiating between East and West compared to North and South.  This is likely caused by our association of North, South, East, and West with up, down, right, left respectively (see left-right confusion). 

Differentiating between East and West will require more cognitive effort than differentiating between North and South.  This implies that East/West (EW) tasks will take longer and be less accurate than the same tasks in the North/South (NS) plane.  Since this is caused by our implicit association with egocentric coordinates, we will see a similar relative difficulty in the left/right tasks compared to above/below tasks. 

Experiment (N=47) 
Participants were instructed to answer a series of randomized true/false statements accompanied by a map, using the 0/1 keys on their keyboard (1==true, 0==false).  To measure cardinality bias, the participants were shown a map with two colored locations and were given a statement “The yellow location is _____ of the red location” where the blank was filled with a cardinal coordinate (fig 1).  The same method was applied to egocentric (relative) coordinates using the positioning of a sphere and a cube (fig 2).  The egocentric questions measured the participant’s ability in left/right (LR) and above/below (AB) tasks.  The participants were given 40 questions in total; 10 from each category (NS, EW, AB, LR).

Fig 1: Cardinality Task Example Fig 2: Egocentric Task Example

Results and Discussion 
To measure the difference in response times and prevent data skew, I measured the relative percentage of time spent in each of the four categories and took an average of the percentages.
Percentage of Time Taken by Category(ms) Accuracy by Category (%)

Participants took 8% longer on EW tasks compared to NS tasks and 15% longer on LR tasks compared to AB tasks.  In terms of accuracy, NS tasks outperformed its counterparts by 9% while AB and LR tasks showed no difference 

Experiment 2 (N=248) 
In the first experiment the participants were asked to respond to spatial true/false statements with the 0/1 keys.  Because a participant will typically use their left and right hands to press these keys, it could interfere with quality of the response with questions regarding left/right and East/West (Stroop Effect).  To take this into account, a second test was released which instead required the participants to use the up/down arrow keys to respond true/false. 

Results and Discussion
Percentage of Time Taken by Category (ms) Accuracy by Category (%)

In this version of the experiment, the relative response time difference increased compared to the previous results.   EW tasks took 24% longer and LR tasks took 20% longer.  Participants were 4% more accurate with NS and 3.5% more accurate with AB tasks than their counterparts. 

General Discussion 
There exists a bias in both cardinality and egocentric identification ability in most humans.  It is likely that we associate the two spatial coordinate systems with each other and have a difficult time in the cardinality system purely due to this association. 

In both experiments, the IP and geolocation were recorded from each participant.  A vast majority of participants were located in North America and Europe. 

Task Specialization 
Since the questions were given at random to each participant, I could measure the speed of the testers as they progressed through the experiment, independent from how they performed on the categorical tasks.  On average, the participants increased in response speed over time and failed to suffer from cognitive fatigue.

Time Taken Per Question (ms)


I have to give a huge thanks to the Reddit community for providing all the data points during the experiment.

Take the test yourself to test your own bias.