## 3 Methods
### Materials and Procedures
#### 3.2.2 The Web-Based Assessment Platform \"STM Suite\"  
In order to assess STM for item and order, a dedicated (tailor-made) program was developed and implemented on the LAMP platform, with the use of the library \"jquery\", which is available both as an online and desktop application, either through the use of a local web server on different operating systems or by means of \"portable web server\" applications. The online version and the desktop version are comparable in terms of their interface, reaction time function, and measurement precision, as detected in the \"client\" part of the program. Hence, they are independent of network transmission latency times. The platform provides 18 testing conditions, resulting from the possible combinations of design variables. Each condition consists of 10 trials and an additional example (trial 0) to allow participants to familiarize themselves with the task. The full design structure is illustrated in Table 2.  
The two lists of the first trial pair contain 3 items, the second pair 4 items, and so on, adding one item per trial pair until the last one with 7 items. There are thus five discontinuities in difficulty, from 3 to 7 items (see Figure 1). The combination of input/output variables produces the following four possible conditions: visual-visuomotor (reconstruction), visual-oral (verbal retrieval), auditory-oral (verbal retrieval), and auditory-visual (visual reconstruction). This inevitably entails a high number of levels and conditions. Letter stimuli were B, C, D, F, G, H, L, M, N, P, Q, R, S, T, V, and Z (consonants to avoid lexicalization), shown as capital black letters in white rectangles in the visual presentation. Colour stimuli included 15 coloured rectangles (pink, blue, black, purple, green, grey, orange, yellow, brown, sand, fuchsia, blue, gold, white, and red), the same size as the ones containing letters. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Memory Process** & **Stimulus** & \begin{tabular}{c} **Presentation** \\ **Modality** \\ \end{tabular} & **Input Modality** & \
\begin{tabular}{c} **Output** \\ **Modality** \\ \end{tabular} & **Distractors** &
\begin{tabular}{c} **Articulatory** \\ **Suppression** \\ \end{tabular} \\ \hline Recall & Letters & Sequential & Visual & Visual–motor & With & With \\ Recognition & Colours & Simultaneous & Auditory & Oral response & Without & Without \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Design variables and software structure (STM Suite). Letters and colours are discrete units whose visual representation, contrary to words, does not require any scanning from left to right. This should allow for a certain degree of comparability between the two types of stimuli. Furthermore, letters and colours have a lexical equivalent and also a unique visual representation. Letters and colours are additionally comparable in terms of the ease of naming and approximate range of possible elements, and, as such, they can easily be used in the auditory presentation modality. On each list, the order of both letters and colours was carefully checked in order to avoid the occurrence of highly frequent combinations, e.g., special bigrams (corresponding to single phonemes, e.g., CH, SC, or GN) or combinations of letters that are very frequent in the Italian orthography (e.g., CL, MP, TR). An attempt was made to avoid sequences of similar colours (e.g., sand/pink; grey/sand; light blue/grey; sand/gold, etc.) or combinations of culturally salient colours (i.e., sequences of colours that are reminiscent of football teams or familiar national flags, or of frequently opposed elements such as black and white) (see [72]). Furthermore, an effort was made to ensure that consecutive colours were not phonologically similar (e.g., rosa-rosso [pink-red]) and that letters always differed by more than one single phonetic trait to avoid phonological interference between consecutive items. In all conditions, two lists were presented for each length (number of items).