Sunday, November 13, 2011

5 biais cognitifs qui prouvent que votre cerveau hait la Science.

(Note for the english readers : Below is mostly the french translation of the following blog article : http://gammasquad.uproxx.com/2011/11/five-cognitive-biases-that-prove-your-brain-hates-science#more-49841)

Cela fait maintenant près de deux ans que la question de l'esprit critique et de la rigueur scientifique fait de plus en plus rage dans les conversations que j'entamme avec les gens qui m'entourent.
Dès lors, dès que j'ai vu l'article que je m'apprête à traduire, je me suis dit : "il est temps de relayer plus régulièrement ce type d'informations".
Voici donc la traduction d'un article qui résume 5 raisons qui expliqueraient pourquoi les gens (a priori) censés ont du mal à accepter qu'il serait plus raisonnable de s'en remettre à la science.


(Article écrit par Dan Seitz)
Plus tôt cette semaine, nous avons parlé de parents idiots qui avaient décidé qu'il s'y connaissaient mieux en matière de santé que les docteurs, et ont donc donné à leurs enfants des sucettes infectées à la varicelle plutôt que de les faire vacciner. Il va sans dire qu'une grande partie d'entre nous sont estomaqués de voir à quel point ces gens ont sauté dans le canoe des abrutis et pagayé en direction de la baie Tueur-D-Enfants. Comment est-il possible qu'il n'aient pas prêté une attention particulière à la science ? Sont-ils stupides ?

Il s'agit d'une question qu'on se pose souvent. Richard Muller, un sceptique du climat bien connu, a récemment publié un rapport qui [...] rapporte qu'il avait tort; les changements climatiques sont bel et bien en train d'arriver [...] Et nous avons toujours des sceptiques du changement climatique et ceci ne les a pas freiné. Et il y a toujours des gens qui hurlent que l'évolution est "juste une théorie".

Mais qu'est-ce que c'est que ce bordel ?

La réponse courte : votre cerveau n'aime pas avoir tort. Pas du tout. Et il prendra d'incroyables détours pour se convaincre qu'il n'a pas tort, même quand c'est le cas. Si la science est basée sur l'observation objective des faits, voici 5 biais cognitifs au travail dans notre cerveau qui nous empêche sans cesse d'admettre nos erreurs.

#5) Le biais de la tache aveugle
Vous avez déjà regardé un débat polique et pensé "Oh, mec la solution est pourtant si simple. Si seulement ces personnes pouvaient arrêter de se gueuler dessus. C'est vraiment dommage qu'il n'ont pas une vision des choses aussi libre, claire et intelligente que moi" ?

Bien sûr que oui, vous l'avez déjà pensé. Nous l'avons tous fait. Mais il y a un problème : c'est que de la connerie. Vous êtes biaisé comme le reste du monde, votre cerveau ne va, par contre, pas l'admettre.

Nous avons tous une tendance à être biaisés, de manière étrange, qui nous pousse à nous conidérer comme bien plus objectifs que tous les clowns qui nous entourent. Chacun d'entre nous a un biais cognitif dans notre cerveau qui est convaincu que nous n'avons pas le même nombre de biais cognitifs que les autres, et que nous pouvons donc observer les situations beaucoup plus clairement et objectivement.

En d'autres termes, si quelqu'un vient vous voir avec une vue contraire à ce que vous croyez, vous rejetterez celle-ci puisque, de toute évidence, cette personne doit être biaisée. "Bien sûr que les scientifiques croient en la science ! C'est leur boulot ! Ils sont aveuglés par la science ! Je m'y connais mieux que ces scientifiques biaisés" ! Voilà pourquoi ces parents ont donné à leurs enfants une maladie potentiellement fatale.

#4) La réactance

Nous avons tous déjà entendu de désopilantes phrases toutes faites telles que "Le fruit défendu est le meilleur", mais ce qu'on ne réalise pas c'est que les psychologues sont presque sûrs qu'il s'agit d'une vérité scientifique. A la seule différence qu'ils appellent ce phénomène "réactance", parce qu'ils sont chiants.

La réactance est définie comme "le besoin de faire le contraire de ce qu'une autre personne vous demande de faire, ceci à cause du besoin de résister à l'atteinte perçue de votre liberté comportementale"; en d'autres termes, si quelque vous demande de ne pas faire quelque chose, votre cerveau voudra absolument le faire, parce que c'est marrant d'être un p'tit con. Sérieusement, quelques psychologues pensent qu'une part de ceci s'explique vraiment parce que c'est marrant à faire.

Et ça accable le sens commun de manière assez pratique: les tests de réactance consistent généralement à montrer aux sujets des messages leur demandant de faire des choses du style "se passer du fil dentaire" ou "ne pas s'imbiber d'alcool" et, à coup sûr, les sujets arrêtent de passer le fil dentaire ou encore passent une nuit d'enfer à boire de la gnaule comme si c'était de l'eau parce que le sujet est maître de sa propre personne, bordel, et parce que personne ne lui dira ce qu'il doit faire !

A l'exception de quelques parties de son cerveau, manifestement. Ainsi, pour en revenir à nos "Parents de l'Année", une partie de l'explication de pourquoi ils ont fait ça était parce que tout le monde leur disait de ne pas le faire. Il s'agissait exactement du motif dont ils avaient besoin pour se "rebeller" et... tuer leurs enfants. Mmmh, attendez.

#3) L'ancrage

Pour vous donner une idée du problème de l'ancrage, il s'agit d'un truc dont les types des finances se servent pour se rappeler à l'ordre sans cesse. C'est plutôt simple: quand on prend des décisions on a tendance à se fier beaucoup trop à une pièce d'informations. Une fois qu'on se crée cette "ancre", ça se transforme alors en une sorte de trou noir, aspirant chaque pièce d'information vers lui et la modifiant afin de lui donner une forme bien plus agréable et laisse penser votre cerveau qu'il ne peut pas avoir tort.

Pour reprendre l'exemple de nos abrutis de parents, l'information qu'ils ont ancrée est "certaines études ont montré que les vaccinations peuvent causer l'autisme". Une fois que l'ancre a été forgée, oublie. Tout ce qu'ils pourront entendre par la suite n'aura pas le même poids. Cela va même déclencher un autre biais :

#2) Le biais de confirmation

Vous en avez sûrement déjà entendu parler, c'est plutôt simple : vous cherchez l'information qui soutient votre opinion, et vous interprétez l'information qui ne soutient pas votre opinion d'une manière telle que vous pensez toujours avoir raison. En d'autres mots, votre cerveau va s'assoir et bouder dans un coin dès que quelqu'un n'est pas d'accord avec lui.

C'est tellement envahissant que les scientifiques ont vachement la trouille : le biais de confirmation est la raison pour laquelle toutes les publications scientifiques sont sujets a la critique des pairs, et aussi pourquoi les scientifiques documentent absolument tout. Mais la plupart des gens n'ont pas à faire preuve d'une telle rigueur. Ils n'ont pas à montrer à leurs amis la preuve que les vaccins ont mis leurs enfants en danger. Après tout c'est leurs enfants.

Mais le biais de confirmation ne peut pas être si puissant, hein Les études ont été réfutées, toutes. Tout ce qui est contre le mouvement "anti-vaccin" s'est avéré faux. A un tel point que le cerveau va devoir accepter que, peut-être, il a merdé, c'est pas vrai ?

Faux.

#1) L'effet "retour de flamme"
C'est vraiment facile : si on vous montre des preuves logiques et claires qui réfutent vos croyances, vous ne changerez pas vos croyances. Au contraires, elles vont se renforcer.

Si vous vous êtes déjà demandé comment les personnes avec un diplôme universitaire et une certaine expérience avec la pensée critique peuvent balayer d'un geste de la main des preuves scientifiques bien écrites et bien documentées, vous avez ici un bel exemple. Non seulement le fait de leur montrer qu'ils ont tort ne va pas leur faire changer d'avis, mais ça fera le contraire.


Aucun de ces biais n'est tout puissant, bien sûr; les gens changent d'avis sans arrêt. Ce n'est juste pas un processus appliqué avec loqique et évaluation minutieuse des faits. La plupart du temps, c'est sous-tendu par une sorte de phénomène émotionnel. Donc oui, si on avait envoyé aux parents un petit chien tout velu portant un panneau avec "Sioupléééé, ne donnez pas à vos p'tit bout'chous une vilaine vilaine maladiiiiie", ça aurait sans doute mieux fonctionné....

____________________


Voilà, je suis trop mou pour tout relire et j'espère que les tournures anglaises ne sont pas trop présentes ;-).
Personnellement, sans vouloir rentrer trop dans le débat aujourd'hui (mais puisqu'il s'agissait quand même d'un article de psychologie), je ne peux m'empêcher de penser que c'est ce genre de mécanismes qui explique sans doute pourquoi encore beaucoup de psychanalystes se retranchent derrières des arguments ignorant délibérément les dernières avancées scientifiques en matière de sciences de l'esprit.
Mais bon, il y a bien pire... dans une autre catégorie, je ne parle même pas de cette abomination qu'est le mouvement créationniste... :-)

Et en cadeau, voici une vidéo (en anglais) sur "la pensée critique". Il s'agit pour moi de l'artiste le plus intéressant qu'il m'ait jamais été de découvrir : Tim Minchin.

Bon amusement et merci pour votre lecture ! Bonne fin de w-e !

Monday, October 18, 2010

A home-made file for converting the visual angles into metric size on your computer screen

Hi folks !

I know that, once again, it's been a (long) while since I wrote something. I am really busy because of my last exams, my thesis that I have to start finish and my search of a kickass... good... descent... a job.

In the meanwhile, here's a excel file I just created for those who'd like to have a visual angle convertor.
Indeed, when you're designing an experiment running on a computer, and that you're presenting visual stimuli, you'll have to control the size of the items.
In the literature, they speak about "visual angle". Imagine that,you want to replicate a study where they presented a 2 cm long word on the screen and where the subject sat 60 cm away from the screen. But in your experimental room, they'll have to sit 100 cm away from the screen. You'll have then to adjust the size of the words in order to be perceived as well as the original experiment.

So here are your choices :
- you already have a convertor for that kind of calculations (provided by your super-promotor)
- you like mathematics and you wanna understand why using trigonometry is in fact useful ? (remember the Tan and ArcTan back in secondary school ?)
- or you're lazy and you want to find a program that somebody else did to compute the informations you need (hint : choose this choice).

For downloading it, just click here.

Just enjoy, good luck with your experiment and see you next time.

N.B. : sorry if the few words in the excel file are not that clear or more "frenchy", I originally did it for me... Also, the angle values are in degrees.
N.B. 2: I'll write a short article about divided visual field methodologies next time because I've been shocked to discover the incredible number of studies that did everything and anything but what they should have done... If you're eager to know it, just check the article of Bourne (2006). The divided visual field paradigm : Methodological considerations, Laterality, 11, 373- 393.

Wednesday, June 9, 2010

The gorilla's experiment reviewed : the attentional blindness on TV

This article has been published right after the previous one.
So because I just gave you a huge (!) article to read (I'd be interested in knowing if somebody really read it entirely... Ok, I may summarize it another time if people ask), here is a great break for you.

Time to smartly relax !
Do you remember the monkey's experiment ? (Dude, there are thousands of them...) Ok. The one where you're asked to count the number of passes of a ball between several people ? Does it ring a bell ? Still no ?

Ok, just forget it. Here's a better one, in a similar vein, that I found on Youtube :



Cool, isn't it ? And useful, moreover !

Have a nice week and be careful on the road, the sidewalk and when you meet your advisor in the hallway of your Faculty! Just run... !

The concreteness effect : why is it much more easy to understand what a "chair" is than "freedom" ?

Well, I would say : "bad start : checked. Pure procrastinating waste of time : checked. Blog still unnoticed : checked".
But, in order to be forgiven, I'll give you an extract of a paper I wrote in the frame of a course about "categorization and induction". This may be a little bit long for a blog note, but still, I think that it's worth it, if it can help somebody...

As I told you in my presentation article, I have a deep interest in the semantic processes. This news is no exception and will develop what the concreteness effect is, in semantic and conceptual prossessing. I dropped a big part of my discussion and a proposal I made (you don't really need this...). Ready ? Let's start !

Introduction to the concreteness effect
There has been a wide number of researches about the concrete-word advantage, or concreteness effect, in the psycholinguistic literature. This effect refers to the idea that people perform better when confronted to a task presenting concrete words and/or sentences (i.e., highly imageable words or sentences) than when presenting abstract words/sentences. Evidences has been reported in lexical decision tasks (e.g., James, 1975; Schwanenflugel & Shoben, 1983; Tolentino & Tokowicz, 2009), recall (e.g., Paivio, 1971), word naming (e.g., Bleasdale, 1987), sentence verification (e.g., Holmes & Langford, 1976), sentence reading (e.g., Schwanenfluegel & Shoben, 1983) and bilingual translation (e.g., De Groot, 1992; Van Hell & De Groot, 1998).
However, while a great number of studies observed different results between the concrete and abstract words presentation, various others did not find any evidence in favor of the advantage of the concrete words over the abstract ones (e.g., Feldman, Pastizzo & Basnight-Brown, 2006; Samson & Pillon, 2004; Tokowiz & Kroll, 2007; Van Hell & De Groot, 1998, 2008). Some researches even showed a abstract advantage over concrete words (e.g., Macoir, 2009; Papagno, Capasso and Miceli, 2009; Tokowicz & Kroll, 2007; Van Hell et al., 1998).
In the following sections, I will first describe various fields of investigations debating the existence or not of the concreteness effect. Second, I will develop the different models that have been proposed to explain the advantage or, sometimes, the disadvantage of the concrete words compared to the abstract ones. Third, the abstractness question will be briefly discussed, according to an embodying cognition point of view. And finally, I will summarize these accounts and address a few propositions for future researches.

Behavioral evidences
Literature of the concreteness effect showed in many experiments that participants tend to respond faster and process with better accuracy the imageable words in word naming and lexical decision tasks (e.g., Binder, Westbury, McKiernan, Possing and Medler, 2005; De Groot, 1989; Paivio, 1991). These results will be further developed in the light of neuroimaging and neuropsychological experiments.

Neuroimaging evidences
Electrophysiology
Despite its low spatial resolution, ERP provides a good way to investigate the temporal evolution of the semantic processes. In that perspective, number of electrophysiological studies used the N400, "a negative deflection peaking about 400 ms after the stimulus onset which reflects both context-dependent and context-independent semantic factors" (Kounios, Green, Payne, Fleck, Grondin, and McRae, 2009, p. 96).
Thus, in the frame of the concreteness effect, Kounios, Holcomb and colleagues (1994, 1998) observed a greater difference in the activation of the N400 during the presentation of concrete words compared to abstract ones while making a semantic categorization task or a lexical decision task (Kounios and Holcomb, 1994) and during a congruency judgment task (Holcomb, Kounios, Anderson and West, 1998). But if the concrete words are easier to process, the reason of this greater activation needs to be clarified. According to these authors, concrete items would activate more features than the abstract ones, thus creating a larger amplitude of the N400 due to a bigger effort. Nevertheless, this still does not explain completely the behavioral results.
In a study of Tolentino et al. (2009), the order of presentation of the abstract and concrete words was investigated. In the abstract-concrete order, responses to the concrete words were more negative, while in the concrete-abstract order, ERP responses did not differ.
Finally, in a recent study of Huang, Lee and Federmeier (2010), the LH has been found to process the concrete and abstract words in a qualitatively similar way while the RH elicits a sustained frontal activity when presenting concrete words (which has been related to mental imagery).


fMRI
There exists a important number of neurobiological theories of the semantic memory that postulate that our conceptual knowledge of concrete words (and, sometimes, to a lower degree, also the abstract ones) are grounded in the sensory and motor systems of our brain (e.g., Barsalou, 1999; Prinz, 2002; Damasio, Tranel, Grabowski, Adolphs, Damasio, 2004; Paivio, 1971; ...). This consideration is of major importance because some models attribute the concreteness effect to the imageable features of the concrete concepts. This means that the conceptual processing of this type of concepts would also involve the sensory and motor systems.
Thus, many functional imaging studies examined the brain activity during conceptual processing. For example, Martin (2007) signals that the visual areas are activated when the subjects execute conceptual tasks about animals and that the motor areas are activated during the conceptual processing of tools. Hauk, Johnsrude and Pulvermüller (2004) also report an activation of the premotor and motor areas during a passive reading of face, arms or legs movements. The gustatory areas are activated during the conceptual processing of food (Simmons, Martin & Barsalou, 2005), as well as the olfactive areas when thinking to odors (Gonzalez, Barros-Loscertales, Pulvermüller, Meseguer, Sanjuan, Belloch & Avila, 2006).
Nevertheless, despite the tremendous number of evidence that the sensorial and motor areas are activated during the conceptual processing of words, little fMRI evidence has been found in the concrete vs. abstract distinction. Several studies did not show any activation differences between these types of concepts (e.g., Grossman, Koenig, De Vita, Glosser, Alsop, Detre and Gee, 2002; Noppeney and Price, 2004) with some finding no activation in the ventral temporal lobe where a difference would have been expected due to the visual specialization of this area and its reciprocal connections with other sensory association areas (e.g., Jessen, Heun, Erg, Granath, Klose, Papassotiropoulos and Grodd, 2000, even if they found a greater activation in the parietal lobes when encoding concrete concepts). However, some studies did still find a greater temporal lobe involvement for the processing of concrete words (e.g., Fiebach and Friederici, 2003; Wise, Howard, Mummery, Fletcher, Leff, Büchel and Scott, 2000; Sabsevitz, Medler, Seideberg and Binder, 2005). For example, Sabsevitz et al. (2005) found an greater activation in a bilateral network of multimodal association areas for concrete words while abstract concepts activated almost exclusively the LH. More generally, Jefferies et al. (2009) performed a meta-analysis of 12 neuroimaging studies which, taken together, showed a greater activity of the occipital, posterior infero- and medial anterior temporal areas for concrete words (these regions are known to be related to visual object recognition, mental imagery and picture-based semantic tasks). However, abstracts words tended to activate more the left superior temporal lobe (which has been related to speech comprehension and intelligibility).
Finally, concrete words have been shown to enhance the activation of the hippocampal structure (Fiebach et al., 2003), a neural circuit known for its involvement in the recollection of memories. This lead Peter and Daum (2008) to discover a greater difficulty to recollect memories of a list of concrete words (learnt in during the first phase of the experiment) than abstract words in older adult population. However, the feeling of familiarity of the presented words did not change between the ages.

Neuropsychological evidences
Brain damaged population
The concreteness effect has also been observed in brain-damaged patients suffering from aphasia and deep dyslexia. Indeed, these subjects made more errors for abstract than for concrete items (e.g., Coltheart, 1980, cited in Jefferies, Patterson, Jones & Ralph, 2009 ; Jefferies et al., 2007). More specifically, as reviewed in Papagno, Capasso and Micelli (2009), aphasic patients had a better performance on concrete over abstract words in "spontaneous speech (Howes & Geschwind, 1964), reading (Coltheart, Patterson and Marshall, 1980), writing (e.g., Bub & Kertesz, 1982), repetition (e.g., Martin & Saffran, 1992), naming (e.g., Frankin, Howard, & Patterson, 1995) and comprehension (e.g., Franklin, Howard, & Patterson, 1994)" (Papagno et al., 2009, p. 1138).

A particular case : the semantic dementia
While the concreteness effect has been reported in the majority of the studies on healthy and brain-damaged subjects, a particular phenomenon has been observed in patients suffering from semantic dementia (SD) : a reverse concreteness effect. In other words, these patients performed better during the processing of abstracts than concrete words, indicating a intriguing preservation of the abstract knowledge (e.g., Yi, Moore, & Grossman, 2007; Macoir, 2009). Neary and colleagues (1998) describe SD as a neurodegenerative disease characterized by a :
severe naming and word comprehension impairment [...] in the context of fluent, effortless, and grammatical speech output; [with a] relative preservation of repetition; and the ability to read aloud and write orthographically regular words. Also there is an inability to recognize the meaning of visual percepts (associative agnosia). This loss of meaning for both verbal and nonverbal concepts (semantics) contrasts with the preservation of visuospatial skills and day-to-day memory (Neary, Snowden, Gustavson, et al., 1998, pp. 1546-1547).

A recent study (Vesely, Bonner, Reilly and Grossman, 2007) also showed a greater degradation of the concrete words during a free-association task compared to abstract ones. Nevertheless, while it would seem pertinent to consider the reverse imageability effect as a new indicator of semantic dementia, this effect seems, up to present, more restricted to some particular cases. For instance, Jefferies et al. (2009) conducted a experiment of synonym judgments on 11 SD subjects without observing any advantage of the abstract items. These authors attribute then this reversal effect as the result of an unusual distribution of atrophy with a spared superior region of anterior temporal lobe and a greater damage in the posterior and the inferior temporal cortex. It also seems important to signal that, even if the concrete knowledge seems more degraded than the abstract one, in some studies, both types of words are significantly touched in SD (e.g., Vesely et al., 2007). These differences may be due to the evolution's stage of the disease. Indeed, to our knowledge, only one research conducted a longitudinal study on a SD patient (Macoir, 2009) and observed that the distinction concrete/abstract was noticeable only at an early stage of the disease, before gradually disappearing.

Explanatory models
Dual coding theory
One of the most famous accounts of the concreteness effect comes from the Dual Coding Hypothesis of Paivio (1971). This model postulates two functionally distinct representational systems : a imagery system for the processing of the non-verbal information carried by the words, and a verbal system for the processing of the linguistic informations.
Thus, according to this hypothesis, concrete words would be mainly represented in the right hemisphere (RH) of the brain, while the abstract words would be represented only in the left hemisphere (LH). ERP results from several studies I previously described would support such a theory in regards to the greater activation of the RH in favor of concrete items during various semantic tasks (Holcomb et al. 1998; Huang et al., 2010; Kounios et al., 1994). The fMRI experiment conducted by Binder, Westbury, McKiernan, Possing and Medler (2005) also support this account by observing a greater activation of the LH while treating abstract words and a bilateral activation during the processing of concrete words. However, a lot of experimental results do not go in the same direction as the Dual Coding theory. For example, Jessen et al. (2000) found a greater activation of the occipital areas (involved in visual processing) while processing abstract concepts than for concretes ones. Also, Fiebach et al. (2003) did not find any processing advantage of the RH for concrete words but reported changes only in the LH with, still, a greater activation for the abstract concepts.
Whether the dual coding theory is right or not about the precise mechanisms underlying the processing of the abstract and concrete words, it has the interest to propose a model where concepts may also be represented by perceptual features. Indeed, by considering the reverse concreteness effect observed in some SD patients, the particular degradation of concrete words may be explained, according to some authors (e.g., Yi et al., 2007), by a loss of visuoperceptual semantic features (partly represented in the ventral temporal lobe, a neural area prone to deterioration due to SD). Thus, a embodied account of the semantic organization might be of particular interest in the light of the (reverse) concreteness effect.

Network accounts
For a long period, models of the semantic organization proposed a localist representation of the concepts whereby the meaning of a word was represented by a single node in a network (Collins and Quillian, 1969). Thereafter, distributed representation models have been proposed in which a concept's meaning is represented over multiple nodes in a network, each of these being activated in a various degree (e.g., Plaut, 1995). Some authors explored then the "semantic richness" of the words as a variable influencing the processing of the concepts (e.g., Kounios, et al., 2009; Grondin, Lupker and McRae, 2009).

Semantic richness and number-of-features
Semantic richness is function of two central properties of word meaning : ambiguity and concreteness. While concreteness has already been much described in this article, it has been proposed that ambiguous words have a richer semantic representation than non ambiguous words because of their multiple meanings leading to a speed advantage of processing during lexical decision and naming (e.g., Hino and Lupker, 1996, cited in Grondin et al., 2009). However, this effect disappears in a categorization task (Hino, Pexaman and Lupker, 2006, cited in Grondin et al., 2009). But, more importantly, semantic richness depends mainly on the number of features (NoF) a concept has (Grondin et al., 2009). So, the higher the NoF is, the better the performance of the subjects (while performing a paced-reading task, as in Pexman, Holyk and Monfils, 2003, cited in Grondin et al., 2009). Yet, the "ease of predication" hypothesis (e.g., Jones, 2002) postulates that concrete concepts have a higher NoF than the abstract ones leading to better overall performance in semantic processing.

Context availability hypothesis
Another explanation for the concreteness effect may be described in terms of "context availability" of the informations needed to process the concepts (Schwanenflugel et al., 1983). According to this theory, abstract concepts are not processed as good as the concrete ones because they usually do not have as much contextual information available to be processed as the concrete ones do. The concrete words would indeed have been more familiar and therefore associated with more propositions in long-term memory. This account has received support from several studies showing that, when presented with as much context information, the abstract concepts are processed as good as the concrete ones in a lexical decision task (e.g., Schwanenflugel et al., 1983; Van Hell et al., 1998).
However, the experiment of Tolentino et al. (2009) is, for example, not entirely consistent with the context availability hypothesis that postulates quantitative differences in a single system because of the interhemispheric differences of activation they reported (see also the dual coding hypothesis arguments).

Other models
Up to present, the models that have been summarized in the previous sections seem to be the major ones. Nevertheless, this should not obliterate other pertinent accounts such as the Sensory/Functional Theory (SFT) (e.g., Warrington & Shallice, 1984) where living things would be much represented by sensory/perceptual attributes, whilst non-living things would be more represented by functional attributes. Another possible account is the Hierarchical Interactive Theory (HIT) of Humphreys and Forde (2001, cited in Macoir, 2009), similar to the SFT but "adopting an amodal theory of semantic memory with separate visual (pictorial and written words) and auditory (environmental sounds and spoken words) inputs" (Macoir, 2009, p. 529).

The abstract concepts question
It has been mainly argued, throughout this article, that abstract concepts do not rely on perceptual features. However, according to Barsalou and colleagues (Barsalou, 1999; Barsalou and Wiemer-Hastings, 2005), abstract concepts may not be represented only by amodal symbols. For example, Barsalou (1999, 2008) proposes that, when a abstract concept has been perceived, subjects create a representation of it by applying three mechanisms : framing, introspection and selectivity. First, the individual will identify a sequence of events indicating the frame in which the abstract concept has been encountered. Then, he will focus on the physical informations of the event as well on the introspective and proprioceptive informations. Finally, the individual will identify the central element of this concept amongst the amount of features that characterizes it. Barsalou (1999) asserts that, once the concept has been perfectly integrated, it will be subsequently simulated directly by the sensori-motor systems.
However, even if this account allows some perceptual simulation of the abstract concepts, Dove (2009) signals that the introspection mechanism will, in turn, evoke other abstract concepts that will also be subjects to a processing as heavy as the first one. Because introspection would be a perceptual simulation associated with judgments formation, these judgments are also likely to contain abstract concepts. Thus, amodal mechanisms would be necessary to short-cut this endless loop.

Discussion
It would be difficult to assert, considering the amount of evidences I described, that there is no such thing as a concreteness effect. Behavioral, electrophysiological, neuroimaging studies and brain-damaged patients present a great source of information regarding the semantic network organization.
However, in spite of all these evidences of different performance and/or neural activity between abstract and concrete concepts, researches showed scattered results. It is then difficult to determine the reason of these different patterns. It is effectively plausible that concrete concepts activate more features (modal and amodal) than abstract concepts. Therefore, the reasoning of dual coding theory, that asserts that concrete concepts will also activate the RH, may sound well-founded due to the imagery specialization of the RH. However, as Kounios et al. (1994) remind it, an ERP activation observed in the RH may in fact originate from the LH. Moreover, embodied cognition theories would argue that concrete (and sometimes abstract) concepts do not only activate visual properties, but also simulate other sensori-motor and introspective representations (e.g., Ghiot and Tettamanti, 2010). It is our opinion that all these different patterns of results come from design differences leading then to different cognitives strategies. As Solomon and Barsalou (2004) showed it, when subjects are asked to perform a superficial semantic task, they may use only a word association strategy (bypassing then the perceptual simulation). More specifically, when performing a property verification task, subjects had to access conceptual knowledge when presenting an associated false property of the initial word (e.g., owl - tree).

Conclusions
From all these researches, it currently seems that the perceptual and the great number of features of the concrete words compared to the abstract ones seem to be the major parameters involved in the (reverse) concreteness effect. However, while network models are able to simulate quite precisely this effect, one drawback of the conceptually embodied models is still the (currently) non-existing computational implementation.
Also, it would be interesting to clarify the influence of some parameters such as the age of acquisition of the words and the level of education of the participants.
Finally, it would be pertinent to investigate to what extend the phenomenon I describe throughout this article would be useful for the improvement of diagnoses, and especially of rehabilitation strategies for brain-damaged people.



For the exact references, just ask me and I'll send them to you.

Friday, May 14, 2010

Bilingual presentation

(English version)
Hello everybody,

As a champion of procrastination, this blog is currently a way for me to participate to my favourite activity but, this time, by being productive at the same time. Because I read a lot about the scientific researches in the field of psychology (cognitive psychology, neurosiences, artificial intelligence, psychotherapy, etc.), I decided to summarize some of the articles I discovered and may be interessant for the community (and also for mine). I also will try to translate some of the articles I post in french.

But let me introduce myself briefly. I graduated in 2009 in psychology (option: clinical neuropsychology) in the Université Catholique de Louvain-la-Neuve (Belgium) and I am currently doing a complementary Master in Artificial Intelligence (option: cognitive sciences) at the Katholieke Universiteit Leuven (Belgium). I am hoping to obtain the possibility to do a Ph.D. in one of these domains in the years to come. And of notable importance : I am a native french speaker (so, please excuse the mistakes I commit but don't hesitate to correct me, in a friendly way ;-)).

Good surfing / procractination with me !

Blink
______________
(French version)

Bonjour à tous,

En tant que champion de la procrastination, ce blog est actuellement un moyen pour moi de participer à mon activité préférée mais, cette fois, en étant également productif.
Le fait que je lise beaucoup d'articles scientifiques dans le domaine des sciences psychologiques (par ex. : psychologie cognitive, neurosciences, intelligence artificielle, etc.) m'a donné l'idée de résumer certains d'entre eux que je trouvais intéressant de partager avec la communauté web. J'essayerai par ailleurs de traduire certains articles en français (par défaut publiés en anglais).

Mais laissez-moi me présenter. Titulaire d'un Master en Sciences Psychologiques (option : neuropsychologie clinique) à l'Université Catholique de Louvain (Belgique), j'accomplis actuellement un Master complémentaire en Intelligence Artificielle (option: sciences cognitives) à la Katholieke Universiteit Leuven (Belgique). Je suis d'ailleurs actuellement dans l'espoir d'obtenir un poste de doctorat dans l'un de ces domaines de recherches.

Bon surf et bonne procrastination en ma compagnie !

Blink

Sociable