Clarke, AaronHerzog, M.Francis, G.2020-04-092020-04-0920141664-1078http://hdl.handle.net/11693/53575Experimentaliststendtoclassifymodelsofvisualperceptionasbeingeitherlocalorglobal,andinvolvingeitherfeedforwardorfeedbackprocessing.Wearguethatthesedistinctionsarenotashelpfulastheymightappear,andweillustratetheseissuesbyanalyzingmodelsofvisualcrowdingasanexample.Recentstudieshavearguedthatcrowdingcannotbeexplainedbypurelylocalprocessing,butthatinstead,globalfactorssuchasperceptualgroupingarecrucial.Theoriesofperceptualgrouping,inturn,ofteninvokefeedbackconnectionsasawaytoaccountfortheirglobalproperties.Weexaminedthreetypesofcrowdingmodelsthatarerepresentativeofglobalprocessingmodels,andtwoofwhichemployfeedbackprocessing:amodelbasedonFourierfiltering,afeedbackneuralnetwork,andaspecificfeedbackneuralarchitecturethatexplicitlymodelsperceptualgrouping.Simulationsdemonstratethatcrucialempiricalfindingsarenotaccountedforbyanyofthemodels.Weconcludethatempiricalinvestigationsthatrejectalocalorfeedforwardarchitectureofferalmostnoconstraintsformodelconstruction,asthereareanuncountablenumberofglobalandfeedbacksystems.Weproposethattheidentificationofasystemasbeinglocalorglobalandfeedforwardorfeedbackislessimportantthantheidentificationofasystem’scomputationaldetails.Onlythelatterinformationcanprovideconstraintsonmodeldevelopmentandpromotequantitativeexplanationsofcomplexphenomena.EnglishFeed-forwardHierarchicalmodelsFeedbackScene processingObject recognitionVisual crowding illustrates the inadequacy of local vs. global and feedforward vs. feedback distinctions in modeling visual perceptionArticle10.3389/fpsyg.2014.01193