1.3 EVOLUCIÓN HISTÓRICA DE LA REPERFUSIÓN DEL INFARTO
1.3.4 Contexto científico en la concepción del estudio GRACIA-2
Step 1: Pretest Check subjects' perception of orthographically similar words
Step 2: Repetition Speed (Vissim & Control lists in counterbalanced order)
Vissim list items (1-3) x 10; (4-6) x 10; (7-8) x 10 Control list
Step 3: Reading Speed (Vissim & Control lists in counterbalanced order)
Vissim list items (1-8) x 6 Control list
Step 4: Memory Span (Vissim & Control lists in counterbalanced order; suppression condition according to Latin Square)
Similarity Suppression
_______ Nil_______ _____ Manual — - English High
(Vissim List) Low
These lists were matched for articulation, canonical form, rhyme, spoken English length, total letters, sign length, cherological similarity, parts o f speech, familiarity, and orthographic regularity.
Each master list was used to compile two sets o f production speed stimuli in the same manner as Experiments 1, 2 and 3. The repetition set was created by dividing each master list into one item pair and two item triplets. The reading set consisted o f two inventories o f 48 items, formed by randomly repeating the eight items in each master list six times.
Each master list was also used to devise a set o f practice memory lists and a set o f experimental memory lists, again following the same procedures as the previous experiments. The practice set consisted o f 10 different item pairs taken from each master list. The experimental set was composed o f lists which varied in size from two to eight randomly ordered items. Four lists were constructed at each list size, so the complete Vissim and Control sets each contained 28 lists.
After checking that everyone correctly perceived the items in the master lists, two speed measures and then one span measure were obtained from every subject for the Vissim and Control lists.
The first speed measure was repetition performance. This was derived from three combined repetition trials in which the subjects produced in their primary language the two sequences-of word triplets and one sequence o f word pairs 10 times as fast as possible. Scores were expressed in seconds to completion and items per second. The second timed measure incorporated a reading performance score. This was obtained by recording the time taken to read each o f the two inventories o f 48 words at maximum speed.
In the memory span task, there were three suppression conditions: nil, manual, and English. In the nil condition, subjects watched the items on the monitor, then attempted to recall them in order. In the manual suppression condition, all groups followed the procedure implemented in Experiment 4: during presentation o f the stimuli, all subjects repeatedly drummed their fingers on the table, crossed their arms and fluttered their fingers against their cheeks. In the English suppression condition, the procedure used in Experiment 5 was adoptedl subjects counted from one to five throughout the presentation o f the memory stimuli. In each case, recall was made without interference, immediately after the stimuli were presented.
All the items to be recalled were presented orthographically at the rate o f one per second. As in all previous experiments, subjects were given practice trials in the memory span task until they made four successive correct responses. In the experimental phase, all subjects began with four trials o f the two-item lists, and continued until they failed at least three o f the four trials with a given number o f items per list. All the items in a particular list had to be recalled in their correct order before that list was scored as correct. Subjects' scores were calculated as 1.0 plus .25 for each list correctly recalled up to their ceiling.
The order o f presentation was counterbalanced across groups, with half the subjects receiving the Vissim list first, and the remainder, the Control list. Within each list, the suppression sequence for nine o f the subjects in each group was determined by a Latin Square; the sequence for the tenth subject was allocated randomly. Both the timed and memory tasks for a particular list were completed before moving to the remaining set o f eight items.
Results were analysed using repeated measures ANOVAs, and two-tailed t tests o f planned contrasts.
7.2
Methodological considerations
7.2.1 Orthographic similarity
There is some debate surrounding the issue o f how orthographic similarity may best be measured. Conrad (1979) commented in his discussion o f phonetic and visual similarity: "Inevitably it becomes necessary to establish somewhat arbitrary rules of similarity for both sets" (p. 94). He eventually settled for the construction o f a list using words with an equal number o f letters and employing a distinction between the presence or absence o f ascenders and descenders, and the exclusion o f the letter "i" which is "narrow". Succeeding tests with hearing subjects showed that Conrad's visually similar list when presented in "visual noise" was identified more poorly than a control list. Conrad's verification notwithstanding, subsequent research has provided guidelines for a more stringent test o f orthographic similarity.
In particular, evidence has accumulated in favour o f two dimensions - either identification o f the overall word shape (e.g. Besner, 1989), or analysis o f the constituent letters (e.g. the proofreading studies o f Monk and Hulme in 1983, and o f Healy and Cunningham in 1992), or both (Guttentag, 1981). In the present study, attention was paid to similarity o f letter and word shape, because o f the subjects' widely varying skills and approaches to reading.
Following Geyer (1977), letters were classified according to whether they contained ascenders (e.g. "h"), descenders (e.g. "p"), or were neutral (e.g. "n"). In addition, since Healy, Volbrecht, and Nye (1983) had demonstrated that subjects tolerate misspellings as long as letter envelope is preserved, attention was paid to the letters' individual features. Letters which comprised a whole or partial circle were classified together (e.g. "a", "e", and "o") as were domed letters that incorporated at least one neutral straight line ("m", "n", and "r").
Additionally, in view o f the work of Haber and Haber (1981) concerning letter density, it was considered mandatory that all the words in the visually similar stimulus set should contain the same number o f letters.
A final condition was that words were to be constructed with matched letters occurring at identical serial positions.
Eventually, a list was selected which contained eight items all with one ascender ("b", "d" or "h") followed by three neutral letters. Thus, all eight words embodied a
similar overall configuration. This visually-similar list was called "Vissim" and its items are listed below, together with those o f the visually different "Control" list.
Vissim Control
bare
bone
go
cord
bore
dame
king
fought
done
hero
very
badge
here
home
peach
may
7.2.2 List controls
As outlined below, the Control list was matched on articulation, canonical form, rhyme, spoken English length, total letters, sign length, cherological similarity, parts o f speech, familiarity, and orthographic regularity.
(i) A rticulation
The Vissim list was composed o f only 9 letters whilst the Control list had 17 letters. Therefore some similarity o f articulation arose in the former list because o f its repeated letters. The three vowels "a", "o", and "e" actually produced seven different articulatory patterns in the list o f eight words, so they did not produce undue articulatory similarity amongst the Vissim items. But the six consonants were each associated with only one sound, which increased the inter-item articulatory similarity, and hence the difficulty level o f the Vissim list (from Experiment 1).
Therefore the initial and final consonants in the Control list also contained consonants which were visually distinct, but articulated similarly. For example, the first three words in the Vissim list
(bare, bone, bore) all began with "b". The first three words
in the Control list(go, cord, key) began with "g", "c" and "k" which all had a similar
place o f articulation.Working through the Vissim list, the next two words
(dame, done) began with
"d" and the corresponding two control words(fought, very) began with the similarly
articulated consonants " f and "v".Finally, the words with an initial "h"
(hero, here, and home) in the Vissim list
were paired withbadge, peach, and may in the Control list because "b", "p", and "m"
were all articulated at the front o f the mouth.The final consonants were analysed in the same fashion. In the Vissim list,
bone
and done shared the "n" sound so the Control list was constructed with cord andfought
ending in the similarly articulated letters "d" and "t".The remaining words in the Vissim list to share a common final consonant were
dame and home - so badge and peach were the remaining words in the Control list to
contain end consonants with like articulation.(ii) Canonical form
Each list contained three CV forms, four CVC forms, and one CVCV form (where C refers to consonants and V, to vowels).
(iii) Rhyme
The Vissim list included two words with rhyming vowel sounds (bone and home) and the Control list also had two words with rhyming vowel sounds but distinct orthographic representations - cord and fought.