An extension of the Stroop Effect: The naming of quantities using numerical and non-numerical characters

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An extension of the Stroop Effect: The naming of quantities using numerical and non-numerical characters.

Introduction

This experiment aims to investigate people’s ability in the naming of quantities of numeric vs. non-numeric characters; it aims to look at the interference, which may occur when people attempt this naming of quantities task.

The experiment is loosely based on the Stroop effect. This is a task in which participants are shown words written in different coloured inks. When the task is to read the word, participants are able to ignore the colour of the ink. However, when the task is to name the ink colour, they are unable to ignore the visual effect of the word form (i.e. the word GREEN printed in red ink). As stated by (SORT OUT REFERENCE) ‘If the word conflicts with the ink colour, they are consistently slower to respond than for control stimuli, and they are faster if the word agrees with the ink colour (e.g. RED in red ink)’. (REFERENCE).

The Stroop effect was first described in 1935 by John Stroop, although James Cattell 50 years earlier had reported that objects and colours took longer to name aloud than the corresponding word took to read aloud. (REFERENCE?? – McCleod).

In two early experiments Stroop compared reading a list of words printed in black with reading the same list of words printed in incongruent colours ‘Stroop found that there was little difference in reading time for the two lists’ (REFERENCE). Stroop then compared the naming of colours for a list of solid colour squares with the naming of colours for a list of words printed in incongruent colours, ‘subjects averaged 74% longer to name ink colours of incongruent words’ (REFERENCE??).

These results seemed to suggest that a certain level of interference was occurring which was leading to confusion in naming the colours.

Since this research various experiments have been carried out in order to try and further explain the stroop phenomenon, but as yet not one explanation has proved to dominate. There have however been various recurring points identified including; no sex differences, interference is at its highest level at age 7-9yrs, degree of practice crucial, and that the stroop effect is perhaps a measure of attention rather than learning. (REFERENCE??)

The most prevalent approaches to explaining the Stroop phenomenon are hemispheric differences, relative speed of processing and automaticity, the effectiveness of these approaches have been extensively researched.

The hemispheric differences approach is based on the idea ‘if an identification task involves functions tapping both hemispheres (as the stroop does), it is more cognitively complex and thus requires more time to process’. (REFERENCE). In addition it is thought that the left hemisphere generally shows more interference than the right, and as it is that hemisphere that deals with verbal processing, this perhaps explains why subjects take longer to name ink colours of incongruent words. Schmit and Davis have tested this hypothesis (1974) cited in McCleod 1991 (SORT OUT REFERENCE), they presented subjects with stroop stimuli displayed only in the left or right visual field and ‘observed greater interference in the left hemisphere, consistent with that hemisphere’s dominant role in verbal processing.’ (PG> REFERENCE). In order to relate this approach to our current experiment on the naming of quantities we would have to consider the fact that the verbal processing taking place is the naming of quantities and the visual processing is what characters are actually presented. As interference is greater in the left hemisphere, it should /be harder to name the quantities when viewing incongruent quantities of similar numerical characters.

The relative speed of processing approach states that word-processing occurs much faster than colour processing, therefore in conjunction with the stroop effect words are read faster than colours can be named ‘thus in a situation of incongruency between words and colours, when the task is to report the colour, the word information arrives at the decision process stage earlier than the colour information and results in processing confusion.’ (WEBSITE REFERENCE). Hence this approach states that ‘the greater similarity between the names of the two repeating responses should make it harder to select the correct one at the response-production stage’ (REFERENCE).

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In relation to the current study we might expect participants to be slower to name the quantity of incongruent characters, as a result of the characters being read faster than the quantity can be named. Thus when numerical characters are presented that are incongruent with the quantity of characters shown interference occurs and we may expect the reaction time of participants to be slower. (NEED A STUDY?? – Cohen & Dunbar pg.344).

The automaticity model states that reading is an automatic process. People can see words without much effort or consciousness; on the other hand, naming colours is not ...

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