Why does a seemingly rational, sociable person suddenly commit a murder or another serious crime, leaving their friends and neighbours shocked and incredulous? Police and criminal psychologists alike have long been puzzled by such apparently unpremeditated acts.
A group of applied social studies students from the City University of Hong Kong recently got a rare chance to investigate the motives for such unplanned felonies.
Divided into seven groups under the guidance of lecturer Dr Jessica Li, they set out to interview former drug addicts and ex-triad members, and to research a range of criminal activities.
In February, criminology major Chan Tsz-ting visited recovering female drug addicts at the Barnabas Charitable Service Association on Lamma Island. She was surprised to find they all understood the consequences of addiction before plunging into their drug use.
'They just decided to do it. What they told me on the visit proved the Rational Choice Theory (RCT) we learned in lectures,' said Ms Chan.
Dr Li spelled out a long list of seemingly impulsive crimes that are actually committed by choice.
'Even the most seemingly trivial crimes, such as stealing and shoplifting, are conclusive acts from rational choices. Reasons such as youthful innocence and ignorance are often cited to explain juvenile theft. To their surprise, my students discovered that young perpetrators had, however briefly, consciously weighed the pros and cons of the crime before they actually committed them,' said Dr Li.