Response time studies of spatial location and object identity: Examination of the dual pathway model of higher order vision

Relating location and identity in visual object recognition to structure and function within higher order vision have produced diverse cognitive models. The dual pathway model proposes that magnocellular "transient" and parvocellular "sustained" cell sites in occipital cortex project forward in parallel dynamic synchrony through extra-striate regions upward to posterior parietal cortex (PPx) as dorsal ("where") pathway for processing spatial location, and downward to inferior temporal cortex (IT) as ventral ("what") pathway to process color and form for identity, then continue onward to hippocampus/rhinal cortex, binding information in memory.; Fifty-seven university students participated in response time (RT) and accuracy studies judging location, identity, and location + identity of digitized Snodgrass and Vanderwort (1980) drawings of common objects, assessing location and identity to determine effects of: (1) respective rate of processing; (2) hue; (3) spatial frequency filtering (SFF) using Butterworth digital highpass (9.50--11.00 cpd) and lowpass (0.01--1.50 cpd) filters; and (4) speed-accuracy tradeoff (SAT) methodology to reveal ongoing processing.; Owing to the inadvertent use of "only" in my instructions, rather than "Location" and "Identity," I am unable to clearly identify the processes that produced my data. Therefore, I can make no unequivocal claims regarding location versus identity processing, and any statements regarding this data must be viewed as speculative. Future research, however, offers the possibility of clarifying these ambiguities.; Nevertheless, results support and extend the dual pathway model. Location was processed faster than identity. Bw stimuli rt's were faster than rgb stimuli, indicating rgb doesn't aid identity processing. SAT method revealed steep improvement in location during 351--700 ms with sharp fall-off from 701--1050 ms. Identity improved gradually during 701--1050 ms, maintaining during 1051--1400 ms. Conjoint location + identity judgments revealed effects of location, followed afterwards by identity. Finally, a double dissociation occurred: identity was more accurate for unfiltered and highpass objects and location more accurate for unfiltered and lowpass-filtered objects.; Highpass filter inhibited location, while lowpass filter inhibited identity, emulating dorsal and ventral agnosias. SAT illuminated cognitive processing otherwise obscured. SFF/SAT paradigms may help characterize clinical disorders (e.g., Multiple Sclerosis, Alzheimer's Dementia, and Dyslexia).