Salience-driven overestimation of total somatosensory stimulation.
Psychological characterisation of sensory systems often focusses on minimal units of perception, such as thresholds, acuity, selectivity and precision. Research on how these units are aggregated to create integrated, synthetic experiences is rarer. We investigated mechanisms of somatosensory integration by asking volunteers to judge the total intensity of stimuli delivered to two fingers simultaneously. Across four experiments, covering physiological pathways for tactile, cold and warm stimuli, we found that judgements of total intensity were particularly poor when the two simultaneous stimuli had different intensities. Total intensity of discrepant stimuli was systematically overestimated. This bias was absent when the two stimulated digits were on different hands. Taken together, our results showed that the weaker stimulus of a discrepant pair was not extinguished, but contributed less to the perception of the total than the stronger stimulus. Thus, perception of somatosensory totals is biased towards the most salient element. 'Peak' biases in human judgements are well-known, particularly in affective experience. We show that a similar mechanism also influences sensory experience.
Institute of Cognitive Neuroscience, University College London, UK; Neuroscience Research Australia and the University of New South Wales, Australia.
Lee
L
Walsh
Institute of Cognitive Neuroscience, University College London, UK.
James
J
Critchlow
Institute of Cognitive Neuroscience, University College London, UK; Centre for Studies and Research in Cognitive Neuroscience, University of Bologna, Italy; Department of Psychology, University of Bologna, Italy.
Brianna
B
Beck
Institute of Cognitive Neuroscience, University College London, UK; Centre for Studies and Research in Cognitive Neuroscience, University of Bologna, Italy; Department of Psychology, University of Bologna, Italy.
Antonio
A
Cataldo
Institute of Cognitive Neuroscience, University College London, UK.
Lieke
L
de Boer
Institute of Cognitive Neuroscience, University College London, UK. Electronic address: p.haggard@ucl.ac.uk.
Patrick
P
Haggard
D000293:Adolescent; D000328:Adult; D003080:Cold Temperature; D004192:Discrimination, Psychological; D004558:Electric Stimulation; D005260:Female; D005385:Fingers; D006358:Hot Temperature; D006801:Humans; D007600:Judgment; D008297:Male; D017288:Pain Threshold; D010812:Physical Stimulation; D012684:Sensory Thresholds; D055698:Touch Perception; D055815:Young Adult
Perceptual integration; Salience; Somatosensory aggregation; Tactile; Thermal