Visual binding of English and Chinese word parts is limited to low temporal frequencies

Holcombe, AO & Judson, J. In press, Perception
(pdf)

related abstract from the 2003 meeting of the Vision Sciences Society:

BACKGROUND. For cases such as stereodepth, edges, and motion direction, our percepts afford conscious access to high temporal frequency information. For example, percepts of motion direction are accurate even for gratings drifting at 20 Hz- indicating the binding of information from intervals of less than 50 msec. But other judgements, such as which spatially separated colors and orientation are presented simultaneously, are only accurate at less than 5 Hz (Holcombe & Cavanagh 2001). Why the difference? Investigation of the perception of words should help decide between competing theories. Words are identified late in visual processing, leading one theory to predict temporal resolution will be low. Yet we have lifelong experience with processing words in rapid series, leading another theory to predict temporal resolution will be high.

METHODS. To measure the temporal resolution of binding letters into words, in each trial two four-letter strings alternated in the same location for several cycles. Observers discriminated between two pairs of letters strings which were indistinguishable at high temporal frequencies, e.g. observers discriminated (2AFC) "tank" alternating with "mope" from "tape" alternating with "monk". For successful performance, observers had to bind the letters presented simultaneously (forming a word).

RESULTS. Temporal frequency thresholds were remarkably poor for each subject, ranging from 5 Hz (100 msec/word) to as low as 2 Hz (250 msec/word). Binding letters into letter strings which were not words yielded even slower thresholds.

CONCLUSIONS. The low temporal resolution of binding letters into words indicates that decades of training is not sufficient for high-resolution access to stimulus information. Instead, conscious access to high temporal frequencies may be limited to those cases where a detector turns rapidly changing information (e.g. stimulation from rapidly drifting gratings) into a constant percept (e.g. motion direction or depth).


Demonstration

Note: you must fixate (keep your eyes very still) while viewing the movies, as otherwise successive strings will not land on the same patch of retina, allowing you to cheat! Fixating here is more difficult than with other stimuli, perhaps because of the habit of saccading while reading.

 

slow

faster

fastest

NOTE: Movie performance is poorer than in the experiment, and depends on your particular computer, operating system, web browser, web browser version, etc.


More stimuli, including Chinese.