A Theoretical And Experimental Study On Magnitude Module

A theoretical and experimental Study on Magnitude ModuleIn the 1980's,J.Fodor put forward the standards of module.In the late of 1980's,evolutionary psychology appeared and Darwinian module was proposed byevolutionary psychologists.In 2004,Module Psychology was put forward bycombining Fodorian module and Darwinian module.The idea of module psychologymade the study of magnitude module to be possible and necessary.The current studyaims at demonstrating that the hypothesis of magnitude module is possible by the wayof theoretic reasoning and experimental study.The study of magnitude module couldoffer theoretic interpretation for existing experimental findings,and throw light on theunderstanding of magnitude competence.The current study is divided into two parts.The first is to reason the possibilityof magnitude module resorting to the existed findings in the aspect of magnitudeprocessing.In detail,the first part of current study intend to reinterpret the existedfindings by analysing and summarizing the existed findings according to the threeingredients of module.The first essential ingredient of module is inherence.The study on the magnitudecompetence suggested that human infants,human adults and non-human primateshare many common characteristics,and human being's magnitude competence couldtraced back to the evolutionary origins,which argued that inherence is one of theessential ingredients of magnitude module.The second essential ingredient of moduleis domain-specific.More and more findings suggested that manitude competencepossesses of its evolutionary foundation that is independent of linguistic ability.Manyneuropsychological studies of adults with neurological damage strongly indicatc thatnumber knowledge is dissociable from semantic memory (Cappelletti,Butterworth,&Kopelman,2001),and that the semantic memory systems for numerical and non-numerical information are localised in different areas of the brain (Thioux,Seron,& Pesenti,1999).Functional neuroimaging reveals that the parietal lobes,especiallythe intraparietal sulci,are active in numerical processing and arithmetic (Dehaene,Piazza,Pinel,& Cohen,2003),and studies of brainlesioned patients (Cipolotti & vanHarskamp,2001) have identified the left lntraParietal Sulcus (IPS) and the angulargyrus as critical to normal arithmetical performance.These findings indicate thatmagnitude competence is domain-specific.The third essential ingredient of module isencapsulation.The results of number recognise researches such as SNARC effect,Stroop effect could be interpreted by the encapsulation of magnitude module.Additionally,study results about unconscious number processing provide the evidencefor the encapsulation of magnitude module.Magnitude module is divided into number module,analog magnitude mdule anddiscrete magnitude mdule according to the categories of number sense that the stimulicaused.In theoretic part,it is revealed that the existing findings support thehypothesis of magnitude module,however,most of existing studies focused on thenumber module,and the main findings are SNARCeffect,Stroop effect,distanceeffect and priming effect of number.Analog magnitude mdule and discrete magnitudemdule are not explored extensively.Hence,the current study is focused on analogmagnitude mdule and discrete magnitude mdule.The key hypothesis of current study is that the characteristics that numbrermodule manifested when processing number are originated from analog magnitudemdule and discrete magnitude mdule.From developmental perspective of magnitudemodule,the characteristics that numbrer module manifested when processing numberare not existed before children accepte extensive arithmetic training,but themagnitude process of analog magnitude mdule and discrete magnitude mdule mightpossess the characteristics above.The second part of current study is experimental study,which consists of fivestudies.Study 1 aimed at exploring whether SNARC effect exists in area comparisontask and luminance comparison task.In a binary response setting,it has been frequently observed that small numbers are responded to faster with the left hand andlarge numbers with the right hand (i.e.the SNARC effect) which reflects the spatialleft-right orientation of the mental number line (Dehaene,Bossini,& Giraux,1993).So it was worth considering whether spatial associations are exclusively numerical orwhether they could occur with continuous properties of non-numerical stimuli (e.g.area,luminance,hue of a figure;length,width and weight of an object;pitch andloudness of sound).In two experiments,the area and luminance of circle were used ascomparison stimuli to test the hypothesis that not only number comparison task butalso the comparison task of continuous properties of non-symbolic stimulus couldproduce SNARC effect.Both experiment 1 and experiment 2 used numbercomparison task as the index of producing SNARC effect,and the results proved thattwo modes of stimuli presentation were valid.In experiment 1,the area of circle and the semantic of number were used ascomparison stimuli to test our hypothesis.The results indicated that left handresponded faster and more accurately to relative small magnitude of stimuli (area ofcircle or semantic of number) and right hand is faster and more accurate to relativebig magnitude (area of circle or semantic of number).SNARC effect of numbercomparison task in experiment 1 conforms to the study of Dehaene etc.(1993).Inarea comparison task of our experiment 1,bigger circles were answered about 47 msfaster to the right than to the left,and smaller circles were answered about 12 msfaster to the left than to the right.In experiment 2,to explore whether the luminance of stimuli could produceSNARC effect that was found in number comparison task,the luminance of circle wasused as comparison stimuli to test our hypothesis.For luminance comparison weformed five circles with different luminance (from 0 to 255 in RGB -coded shades ofgray) that varied only in brightness with constant hue and saturation.The resultsproved that both number comparison task and luminance comparison task couldproduce SNARC effect.Left hand responded faster to higher luminance circle andright hand responded faster to lower luminance circle.Conclusively,the results of study 1 indicated that SNARC effect could be obtained in area comparison task and luminance comparison task.Furthermore,theresults suggested that (1) distance effect that was observed in number comparison taskalso existed in area comparison and luminance comparison,Stroop effect that wasobserved in number comparison task also existed in area comparison,(2) the responsespeed to area comparison and to luminance comparison was faster than to numericalcomparison.It is found that number comparison task and physical stimuli comparison taskshare the same process mechanism(Gallistel & Gelman,2000).Unconscionsly,Dehaene,Naccache et al.,(1998)and Naccache & Dehaene(2001) revealed that theunconscious semantic priming exists in number process.Hence,in study 2 we inferthat unconscious process might exist in the process of number physical properties.The current study aims at whether priming effect and SNARC-like effect exist in thephysical properties comparison task.Using masked priming procedure (Naccache &Dehaene,2001),in both number comparison task and number physical sizecomparison task,experiment 1 found SNARC effect,priming effect and Stroop effectin 33ms priming condition.Experiment 2 found SNARC effect,priming effect andStroop effect exist in both number comparison task and number cover areacomparison task in 33ms priming condition.Numerical Stroop paradigm revealed that the physical size of number and thenumber of numerals (small magnitude) could automatically activate semanticrepresentation,hence produce interference and facilitation between physical size,number of numerals and number magnitude.Based on this automatic process,weinfer in study 3 that in the task of number(i.e.,quantity of units or individuals)approximate estimation might activate automatically the spacial representation ofmagnitude of number.The current study designed two experiments to test thehypothesis.By using Stroop-like effect as index,the first one explored whether thenumbers of numeral and number magnitude could produce interference andfacilitation;the other experiment explored whether the number(i.e.,quantity ofasterisks) could represent spacially by using SNARC-like effect as index.The resultsrevealed that there exists Stroop-like effect between number of numerals and number magnitude,and there exists SNARC-like effect in the number(i.e.,quantity ofasterisks) comparison task.We also found an order effect,that is to say,when themagnitude of numerals number of standard was smaller than that of comparisonsimuli,Rts were faster,otherwise Rts were slower.SNARC effect can be influenced by children' growing numerical skills and taskdemands.By using number comprison task and area comparison task that are releventto magnitude,in study 4 we test whether 5 year-olds could automatically activates aspatial representation when representing magnitude of Arabic number and magnitudeof circle area.Rts data of number comprison task analysis indicated that there is noSNARC effect,however,distance effect is found.Error rate analysis indicated thatthere is no SNARC effect or distance effect.Rts data of circle area comprison taskanalysis indicated that there are SNARC effect and distance effect.Relatively largecircles are responded to faster with a right response than with a left response andrelatively small circles are responded to faster with a left response than with a rightresponse.Error rate analysis indicated that there exists SNARC effect but no distanceeffect.By using the task of number comprison of numerals,we test whether 5 year-oldscould automatically activate a spatial representation when representing number ofnumerals in study 5.Rts data analysis indicated that there is SNARC-like effect,however the orientation of the SNARC effect was reversed.Relatively more numeralsare responded to faster with a left response than with a right response and relativelyless numerals are responded to faster with a right response than with a left responsc.Stroop effect was not found,which means that number comprison of numerals did notactivate automatically magnitude of numerals.Error rate analysis indicated that thereis no SNARC effect or Stroop effect.The results of five experimental studies suggested that SNARC effect,Stroopeffect,distance effect and priming effect of number when processing number alsoexist in the process of analog magnitude comparison task and discrete magnitudccomparison task.Furthermore,SNARC effect is found in the task of analogmagnitude comparison and discrete magnitude comparison when subjects arc five-year-olds,however in the task of number comparison,five-year-olds do not showSNARC effect.The experimental results support the key hypothesis of current study.In general disscussion,experimental results are interpreted intensively andrationally according to the three ingredients of magnitude module.Further more,anew model about the mechanism of magnitude module is proposed on the basis ofexisted model that explains SNARC effect.