Editing Face perception (section)

==Cognitive neuroscience==
[[File:Glip samar.tif|alt=3D rendering of a purple greeble|thumb|A 'greeble' (nonsense figure used in face recognition experiments)]]
Cognitive neuroscientists [[Isabel Gauthier]] and [[Michael Tarr]] are two of the major proponents of the view that face recognition involves expert discrimination of similar objects.<ref>[https://web.archive.org/web/20060509092446/http://www.psy.vanderbilt.edu/faculty/gauthier/PEN/ Perceptual Expertise Network]</ref> Other scientists, in particular [[Nancy Kanwisher]] and her colleagues, argue that face recognition involves processes that are face-specific and that are not recruited by expert discriminations in other object classes.<ref>{{cite web |title=Evidence against the expertise hypothesis |url=http://web.mit.edu/bcs/nklab/expertise.shtml |website=Kanwisher Lab |access-date=5 February 2024 |archive-url=https://web.archive.org/web/20070820073617/http://web.mit.edu/bcs/nklab/expertise.shtml |archive-date=20 August 2007 |date=20 August 2007}}</ref>

Studies by Gauthier have shown that an area of the brain known as the fusiform gyrus (sometimes called the fusiform face area because it is active during face recognition) is also active when study participants are asked to discriminate between different types of birds and cars,<ref>{{cite journal|last1=Gauthier|first1=Isabel|last2=Skudlarski|first2=Pawel|last3=Gore|first3=John C.|last4=Anderson|first4=Adam W.|title=Expertise for cars and birds recruits brain areas involved in face recognition|journal=Nature Neuroscience|date=February 2000|volume=3|issue=2|pages=191–7|doi=10.1038/72140|pmid=10649576|s2cid=15752722 }}</ref> and even when participants become expert at distinguishing computer generated nonsense shapes known as [[greeble (psychology)|greebles]].<ref>{{cite journal|last1=Gauthier|first1=Isabel|last2=Tarr|first2=Michael J.|last3=Anderson|first3=Adam W.|last4=Skudlarski|first4=Pawel|last5=Gore|first5=John C.|title=Activation of the middle fusiform 'face area' increases with expertise in recognizing novel objects|journal=Nature Neuroscience|date=June 1999|volume=2|issue=6|pages=568–573|doi=10.1038/9224|pmid=10448223|s2cid=9504895 }}</ref> This suggests that the fusiform gyrus have a general role in the recognition of similar visual objects.

The activity found by Gauthier when participants viewed non-face objects was not as strong as when participants were viewing faces, however this could be because we have much more expertise for faces than for most other objects. Furthermore, not all findings of this research have been successfully replicated, for example, other research groups using different study designs have found that the fusiform gyrus is specific to faces and other nearby regions deal with non-face objects.<ref>{{cite journal|last1=Grill-Spector|first1=Kalanit|last2=Knouf|first2=Nicholas|last3=Kanwisher|first3=Nancy|title=The fusiform face area subserves face perception, not generic within-category identification|journal=Nature Neuroscience|date=May 2004|volume=7|issue=5|pages=555–562|doi=10.1038/nn1224|pmid=15077112|s2cid=2204107 }}</ref>

However, these findings are difficult to interpret: failures to replicate are null effects and can occur for many different reasons. In contrast, each replication adds a great deal of weight to a particular argument. There are now multiple replications with greebles, with birds and cars,<ref>{{Cite journal|author=Xu Y|title=Revisiting the role of the fusiform face area in visual expertise|journal=Cereb. Cortex|volume=15|issue=8|pages=1234–42|date=August 2005|pmid=15677350|doi=10.1093/cercor/bhi006 |doi-access=free}}</ref> and two unpublished studies with chess experts.<ref>{{Cite journal|author=Righi G, Tarr MJ|title=Are chess experts any different from face, bird, or greeble experts?|journal=Journal of Vision|volume=4|issue=8|pages=504|year=2004|doi=10.1167/4.8.504|last2=Tarr |doi-access=free}}</ref><ref>[https://www.youtube.com/watch?v=WLQbTd6RFhY] {{Webarchive|url=https://web.archive.org/web/20160428225908/https://www.youtube.com/watch?v=WLQbTd6RFhY|date=28 April 2016}} My Brilliant Brain, partly about grandmaster Susan Polgar, shows brain scans of the fusiform gyrus while Polgar viewed chess diagrams.</ref>

Although expertise sometimes recruits the fusiform face area, a more common finding is that expertise leads to focal category-selectivity in the fusiform gyrus—a pattern similar in terms of antecedent factors and neural specificity to that seen for faces. As such, it remains an open question as to whether face recognition and expert-level object recognition recruit similar neural mechanisms across different subregions of the fusiform or whether the two domains literally share the same neural substrates. At least one study argues that the issue is nonsensical, as multiple measurements of the fusiform face area within an individual often overlap no more with each other than measurements of fusiform face area and expertise-predicated regions.<ref>{{Cite journal|author1=Kung CC|author2=Peissig JJ|author3=Tarr MJ|title=Is region-of-interest overlap comparison a reliable measure of category specificity?|journal=J Cogn Neurosci|volume=19|issue=12|pages=2019–34|date=December 2007|pmid=17892386|doi=10.1162/jocn.2007.19.12.2019|s2cid=7864360|url=https://figshare.com/articles/journal_contribution/6616853|access-date=31 March 2021|archive-date=2 June 2021|archive-url=https://web.archive.org/web/20210602121634/https://figshare.com/articles/journal_contribution/Is_region-of-interest_overlap_comparison_a_reliable_measure_of_category_specificity_/6616853|url-status=live}}</ref>

fMRI studies have asked whether expertise has any specific connection to the fusiform face area in particular, by testing for expertise effects in both the fusiform face area and a nearby but not face-selective region called LOC (Rhodes et al., JOCN 2004; Op de Beeck et al., JN 2006; Moore et al., JN 2006; Yue et al. VR 2006). In all studies, expertise effects are significantly stronger in the LOC than in the fusiform face area, and indeed expertise effects were only borderline significant in the fusiform face area in two of the studies, while the effects were robust and significant in the LOC in all studies.{{Citation needed|date=December 2010}}

Therefore, it is still not clear in exactly which situations the fusiform gyrus becomes active, although it is certain that face recognition relies heavily on this area and damage to it can lead to severe face recognition impairment.{{cn|date=January 2025}}