Monday, 8 March 2010

We're slower at processing touch-related words than words related to the other senses

People are slower at responding to tactile stimuli than to input from the other senses. It's not immediately obvious why this should be. It's unlikely to be for mechanical reasons: the retina in the eye is slower at converting input into a neural signal than is the skin. Psychologists think the answer may have to with attention. Perhaps we're not so good at keeping our attention focused on the tactile modality compared with the others. Now Louise Connell and Dermot Lynott have added to the picture by showing that the tactile disadvantage extends to the conceptual domain. That is, we seem to be slower at recognising when a word is tactile in nature than we are at recognising whether words are visual, to do with taste, sound, or smell.

The researchers had dozens of participants look at words on a screen, presented one at a time, and press a button to say if they were related to the tactile modality (e.g. 'itchy') or not. Some words were tactile-related whilst others were fillers and related to the other senses.

The same task was then repeated but with participants judging whether the words were visual-related, auditory and so on, with each sense dealt with by a new block of trials. The key finding is that participants were much slower at this task in the tactile condition than for the other senses. This was the case even when words were presented for just 17ms, which is too fast for conscious detection but long enough for accurate responding.

To make sure the slower performance in the tactile condition wasn't to do with the response requiring a button press (which inevitably causes tactile stimulation), the researchers repeated the experiment with vocal responding via a microphone. The results were pretty much the same.

Ensuring they left no stone unturned, Connell and Lynott also conducted a final experiment to check that there isn't something about tactile words, besides their touchiness, that makes them slower to process. To do this they used words that have both visual and tactile qualities - examples include shaggy and spiky - and they mixed these in among filler words that related to the other senses. The same words were used in the tactile condition (in which participants had to say whether each word was tactile-related or not) and a visual condition. Once again, participants were significantly slower in the tactile condition.

Connell and Lynott say their findings provide further evidence for the tactile sense having a processing disadvantage relative to the other senses. They think this is because there's little evolutionary advantage to sustaining attention to the tactile modality whereas there are obvious survival advantages with the other senses, for example: ' hunting, where efficacious looking, listening and even smelling for traces of prey could afford an advantage.' You may think of pain and damage detection as reasons for paying sustained attention to the tactile domain, but remember these are served by spinal reflexes. 'We do not wait for the burning or stinging sensation to register with the attentional system before responding,' the researchers said.

ResearchBlogging.orgConnell L, & Lynott D (2010). Look but don't touch: Tactile disadvantage in processing modality-specific words. Cognition, 115 (1), 1-9 PMID: 19903564

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.


Justin Grace said...

If we think about this in terms of "motorness" rather than tactility it may become apparent that all response modes require motor coordination (either button press or vocalic) which may interfere with ones judgement on tactile sensations; being inherently motor-related through proprioceptic, somatosensory and kinesthetic mechanisms.

This position is backed up from work looking at embodiment that shows how language-related motor resonance can interfere with fine tuned motor responses. Unfortunately it is very difficult to find a method of measuring behavioural responses that does not require motion.

My suggestion would be to move toward ERP experiments investigating mismatch negativity, and see if this has a longer latency for motor words.

Nevyn said...

If it's all motor resonance, I can't see how the motor coordination of speaking aloud would interfere with processing tactile words like 'itchy' in exactly the same way as the motor coordination of pressing a button. Maybe I'm missing something in that explanation.

Anonymous said...

I'd say tactile words are used less than visual or auditory words/metaphors in everyday life; could account for the slight lag in recognition.

Anonymous said...

Nope, all words were matched for frequency and so on. Intriguing finding but.

Anonymous said...

What about the speed of our reactions/reflexes to painful/harmful stimuli, e.g. stepping on a pin or touching something hot? Those are responses involving touch receptors, and they are surely faster than responding to visual stimuli.

Anonymous said...

A long time ago I hypothesised that in cultures prioritising audtion and proprioception (over sight and the complex coding conventions involved in literacy) there would be measureable differences in skills - depending on the sense modes involved. The corollary v a v your findings might be that the congenitally and the early blind, and people in truly non-literate cultures (wait for it - that may be arriving here,soon ...sorry, just joking ...) there might be quicker - and more subtle (difficult to measure!) articulation of sense and response in the 'tactile mode' -

Anonymous said...

When you hear tactile-related words, you involuntarily do a mental ('enactive' or motor imagery) simulation of the experience - that takes up more time/attention.

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