Psychophysics Lab

Topics studied in our lab include

  • Auditory localization - Lateralization
  • Temporal order judgments
  • Visual field asymmetry
  • Attention

Ongoing Research:

Processing speed of temporal order judgment in dyslexia: (Leah Fostick, Harvey Babkoff)
Studies concerning the origin of dyslexia have focused either on the question of whether dyslexia is a language-specific disorder or on dysfunction manifested in deficits of temporal processing. No previous work compared the speed of correct response between these groups. We compared the speed of the correct response of normal adult readers and dyslexics in addition to the accuracy of their responses in judging temporal order of pure tones. The findings show that dyslexics are slower, in addition to being less accurate in processing temporal information of rapidly presented stimuli. We speculate that maybe the slower reading speed in dyslexia may not be rooted only in neurological or physiological deficits, but may result from attempts to reduce the occurrences of errors. Supporting this line of reasoning is the lack of speed-accuracy relationship for the normal readers who, not making readings mistakes do not need to slow down reading speed to avoid them. Recent studies using the global precedence paradigm, indicate that dyslexics differ from normal readers in temporal processing of visual information. Because reading mainly involves rapid processing of visual information, the dyslexics’ slower speed in processing visual stimuli may have a devastating effect on their reading capability.

Upper - Lower visual field differences: (Avi Goldstein, Harvey Babkoff)
The upper and lower parts of the visual field are represented in separate areas in visual cortex: the upper field ventrally below the calcarine fissure and the lower field dorsally above the fissure. Thus the UVF is located closer to the ventral "what" pathway and the LVF closer to the dorsal "where" pathway. In a series of experiments we are investigating whether there are significant functional differences as a result of the anatomical separation.
We have found an UVF advantage for the processing of lexical stimuli (words), that increases with associative priming. The upper-lower asymmetry was strikingly similar to the familiar right-left asymmetry.

In a follow-up study we are exploring whether form and object-identification processing (ventral) lead to UVF advantages while spatial processing (dorsal) lead to LVF advantages.