Hemisphere Specialization
in Processing Familiar Idioms
Jessica Wilcoxson, Tory Larsen, Paul Moes & Judith Vander Woude
Abstract
The present study examined differences in hemisphere responses
to idioms, or figures of speech (i.e., tie the knot). Verbal recordings
of sentences (idioms or literal sentences) were paired with visuallypresented target words associated with the figurative meaning
(idiomatic) or literal meaning of the sentence (literal words), yielding
4 conditions: idiom with idiomatic word (II), idiom with literal word
(IL), literal sentence with literal word (LL), and idiom or literal
sentence with nonword (ILN ).
Reaction time data showed that the left hemisphere was more
active in the processing of all phrase conditions, II, IL, and LL—with
the advantage being smallest in the II condition. ERP data from the
EEG recordings showed greater right hemisphere efficiency in the
II condition, but this difference was greatest for females.
Introduction
Although the left hemisphere (LH) is responsible for most
language processing tasks, studies have shown that the right
hemisphere (RH) is superior for processing non-literal language
(see Paz Fonseca et al. (2009) for a review). The present study
used a method similar to Mashal, Faust, Hendler, and JungBeeman’s (2007) method to investigate these differences.
We predicted that an idiom paired with a literal meaning (e.g., tie
the knot paired with rope) will produce more LH processing of the
last word, while an idiom paired with its more common
―figurative‖ meaning (tie the knot and marriage) would produce
more RH processing. In addition we expected males to show
greater LH/RH differences than females.
Table 1
Methods
Participants: 31 females, 19 males
Task & Conditions:
• Participants listened to over 200 recorded
sentences, and then viewed a ―target word‖ on the
computer screen that represented either the literal
meaning of the sentence or the idiomatic,
―figurative,‖ meaning of the sentence (idioms only)
[See Table 1].
• The final target word was presented for 200
milliseconds either to the left visual field (LVF) or
right visual field (RVF). In addition, 1/3rd of the
sentences were followed by a ―non-word‖ (e.g.,
―glurky‖).
Response: Participants indicated if the visual display
was a ―word‖ or ―non-word‖ using a button press.
Measures:
Reaction times and percent correct for correct word
identifications were recorded.
EEG (brain waves) were recorded in response to the final
word presentation. From this we calculated the wave
response to the event (last word) called the Event Related
Potential (ERP) a measure of brain efficiency.
Design Summary:
Independent Variables:
• 4 sentence-word combinations
• LVF vs. RVF
• Male vs. Female
Dependent Variables:
• RT, Percent Correct
• EEG (ERP) ―efficiency measure‖
(see illustration, far right)
Discussion
Results
Figure 1
The pattern of reaction time results suggests that words associated with the literal meaning of an idiom
(idiom-literal) are processed faster in the Left Hemisphere (LH) – compared to the Right Hemisphere (RH),
while the words associated with the idiomatic meaning of an idiom (idiom-idiomatic) still show a LH
advantage, but the advantage is reduced. In addition, females show a general pattern of reduced LH
advantage, except for the idiom-idiomatic condition.
Figure 2
The EEG (ERP) ―brain efficiency‖ measure shows that the literal-literal condition produced greater LH efficiency,
while the idiom-literal condition produced equal hemisphere efficiency, and the idiom-idiomatic condition produced
greater RH efficiency – all suggesting that as the conditions involved more figurative processing more RH
processing was produced. In addition, females show a general pattern of reduced LH advantage and greater RH
advantage – especially for the idiom-idiomatic condition – relative to males.
The results confirm the hypothesized pattern.
While RT and ERP data present slightly different
patterns, taken together they support greater
involvement of right hemisphere processing of
idiomatic phrases and meanings. In addition, ERP
results confirm a greater involvement of RH
language processing for females – especially for
figurative meanings.
References
Mashal, N., Faust, M., Hendler, T., & Jung-Beeman, M. (2007). Hemispheric differences in
processing the literal interpretation of idioms: Converging evidence from behavioral and
fMRI studies. Brain and Language, 100(2), 115-126.
Basic design and procedure for the study. The three main conditions have
three combinations of phrase and target word; the fourth ―control‖ condition
presents a non-word after an idiom or literal sentence.
Paz Fonseca, R., Scherer, L. C., Rosa de Oliveira, C., de Mattos Pimenta Parente, M.
(2009). Hemispheric specialization for communicative processing: neuroimaging data on
the role of the right hemisphere. Psychology & Neuroscience, 2 (1), 25 – 33.