Evaluating large language models' ability to understand metaphor and sarcasm using a screening test for Asperger syndrome

Metaphors and sarcasm are precious fruits of our highly-evolved social communication skills. However, children with Asperger syndrome are known to have difficulties in comprehending sarcasm, even if they possess a certain level of verbal IQ sufficient for understanding metaphors. Given that, a screening test that scores the ability to understand metaphor and sarcasm has been used to differentiate Asperger syndrome from other symptoms exhibiting akin external behaviors (e.g., attention-deficit/hyperactivity disorder). This study uses the standardized test to examine the capability of recent large language models (LLMs) in understanding human nuanced communication. The results divulged that, whereas their ability to comprehend metaphors has been improved with the increase of the number of model parameters, the improvement in sarcasm understanding was not observed. This implies that an alternative approach is imperative to imbue LLMs with the capacity to grasp sarcasm, which has been associated with the amygdala, a pivotal cerebral region for emotional learning, in the case of humans.