Comprehension of Morse Code Predicted by Item Recall From Short-Term Memory
Guediche, S., & Fiez, J.A. (2021). Comprehension of Morse code predicted by item recall from short-term memory. Journal of Speech, Language, and Hearing Research, 64(9), 3465-3475. Doi:10.1044/2021_JSLHR-21-00042
Laburpena
Purpose: Morse code as a form of communication became
widely used for telegraphy, radio and maritime communication,
and military operations, and remains popular with ham radio
operators. Some skilled users of Morse code are able to
comprehend a full sentence as they listen to it, while others
must first transcribe the sentence into its written letter
sequence. Morse thus provides an interesting opportunity
to examine comprehension differences in the context of
skilled acoustic perception. Measures of comprehension
and short-term memory show a strong correlation across
multiple forms of communication. This study tests whether
this relationship holds for Morse and investigates its underlying
basis. Our analyses examine Morse and speech immediate
serial recall, focusing on established markers of echoic
storage, phonological-articulatory coding, and lexicalsemantic
support. We show a relationship between Morse
short-term memory and Morse comprehension that is not
explained by Morse perceptual fluency. In addition, we
find that poorer serial recall for Morse compared to speech
is primarily due to poorer item memory for Morse, indicating
differences in lexical-semantic support. Interestingly,
individual differences in speech item memory are also
predictive of individual differences in Morse comprehension.
Conclusions: We point to a psycholinguistic framework
to account for these results, concluding that Morse functions
like “reading for the ears” (Maier et al., 2004) and that
underlying differences in the integration of phonological
and lexical-semantic knowledge impact both short-term
memory and comprehension. The results provide insight
into individual differences in the comprehension of degraded
speech and strategies that build comprehension through
listening experience.