Book review: Are we blind to meaning? Not a chance, it captures attention! Inattentional Blindness. Arien Mack and Irvin Rock. MIT Press, Cambridge, MA. No. of pages 273. ISBN 0-262-13339-3. Price $37.50 (hardback).
✍ Scribed by Veronica J. Dark; Brian T. Crabb
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 57 KB
- Volume
- 13
- Category
- Article
- ISSN
- 0888-4080
No coin nor oath required. For personal study only.
✦ Synopsis
The research began as an attempt to identify stimulus characteristics that are processed without attention. Because extant claims about preattentive processing were derived from procedures like visual search, which require intentional processing, the authors discounted them. They reasoned that for something to be processed without attention, the processing must be done without expectancy or intent. So, they developed an inattention procedure in which participants were asked to do a dicult discrimination task (usually judging whether the vertical or horizontal arm was longer in a 200-ms masked cross). The third or fourth trial was an inattention trial in which a critical stimulus was presented with the discrimination stimulus. Immediately after making the discrimination response, participants were asked if they noticed anything dierent. Because it is irrelevant and completely unexpected, there is no intent to process the critical stimulus. Failure to notice the critical stimulus de®nes inattentional blindness (IB).
Stimulus location aected the level of IB. If the zone of attention comprises a circle around the discrimination cross, then stimuli outside the zone produced greater IB than stimuli within it. IB was greatest when critical stimuli were foveal and discrimination stimuli were parafoveal. This surprising ®nding was interpreted in terms of inhibition of attention.
IB occurred for many features described as preattentively processed in the literature. Texture segregation and grouping by proximity and similarity went unnoticed in the background as did a single dierently coloured or shaped stimulus. Studies with a geometric shape as the critical stimulus on an empty background showed higher IB to shape than to colour or location. IB was found for shape even when the stimulus moved or ¯ickered. IB also was found with auditory and touch stimuli.
IB was not found for some meaningful stimuli. Speci®cally, there was no IB when the participant's name was the critical stimulus, although IB occurred when a vowel in the name was changed or letters were omitted. Highly salient words (e.g. rape) produced less IB than higher frequency words (e.g. the). Happy faces did not produce IB, but sad and neutral faces did. However, with the exception of a swastika and a stick-®gure person, symbols generally produced high levels of IB.
The authors acknowledge that they began the research assuming that any processing of the critical stimulus on the inattention trial was processing without attention, but by the end, they conclude that all conscious perception depends on attention. Therefore, factors associated with low levels of IB are factors that attract attention. Based primarily on the ®nding that meaningful stimuli show less IB, the authors interpret their ®ndings as support for a late-selection view of attention. They reason that if meaningfulness aects selection, then stimuli must be deeply processed before attracting attention. Thus, the authors assume a serial model of perceptual processing in which sensory information produces an implicit perceptual representation, which then can be selected by attention into conscious awareness. The implicit percept is fully analysed and capable of supporting implicit memory. This conclusion was based on the ®nding that stimuli producing IB in¯uenced responses on word-stem completion and picture selection tasks given immediately after inattention trials.