Cognitive psychologists have shown that people judge a type of event as being more likely to occur if they can more easily retrieve instances of that event from memory. This is called the "availability heuristic." Child abductions are now reported in the media more widely than they were 50 years ago, and parents now have a greater fear of child abduction. A social psychologist might explain this greater fear in terms of the availability heuristic: Because of greater media coverage of abductions, parents can more easily retrieve instances of abductions from memory and therefore overestimate how common they are. This psychologist's explanation is at the level of: