--- abstract: 'Assimilation and contrast have opposite effects: Contrast leads to an increase of perceived differences between neighbouring fields, whereas assimilation leads to a reduction. It is relatively easy to demonstrate these effects, but the precise localisation of these effects in the perceptual system is not yet possible. In an experiment the strength of assimilation effects was modified by adding spatial noise. By varying the localisation in perceived space of the added noise (by presentation of the noise pattern with different binocular disparities) the masking effect of this noise can be influenced. Masking caused by binocularly disparate noise is less than masking caused by binocularly non-disparate noise. Our conclusion is that the effect at least partly occurs beyond the (binocular) locus of separation in different depth planes. A similar approach, involving moving noise, will also be presented. Finally, several demonstrations show that images that are peripherally similar can give rise to differences in the perceived amount of assimilation. These effects further indicate that a central mechanism is involved in assimilation.' altloc: [] chapter: ~ commentary: ~ commref: ~ confdates: ~ conference: ~ confloc: ~ contact_email: ~ creators_id: [] creators_name: - family: de Weert given: Charles M. M. honourific: '' lineage: '' - family: van Kruysbergen given: Noud A.W.H honourific: '' lineage: '' date: 1997 date_type: published datestamp: 1998-05-11 department: ~ dir: disk0/00/00/06/59 edit_lock_since: ~ edit_lock_until: ~ edit_lock_user: ~ editors_id: [] editors_name: [] eprint_status: archive eprintid: 659 fileinfo: /style/images/fileicons/text_html.png;/659/1/bressan5.html full_text_status: public importid: ~ institution: ~ isbn: ~ ispublished: pub issn: ~ item_issues_comment: [] item_issues_count: 0 item_issues_description: [] item_issues_id: [] item_issues_reported_by: [] item_issues_resolved_by: [] item_issues_status: [] item_issues_timestamp: [] item_issues_type: [] keywords: 'assimilation, spreading' lastmod: 2011-03-11 08:54:10 latitude: ~ longitude: ~ metadata_visibility: show note: ~ number: ~ pagerange: 1217-1224 pubdom: FALSE publication: Perception publisher: ~ refereed: TRUE referencetext: ~ relation_type: [] relation_uri: [] reportno: ~ rev_number: 8 series: ~ source: ~ status_changed: 2007-09-12 16:32:36 subjects: - psy-phys succeeds: ~ suggestions: ~ sword_depositor: ~ sword_slug: ~ thesistype: ~ title: 'Assimilation: central and peripheral effects' type: journalp userid: 162 volume: 26