## 2 Materials and Methods
### Materials and Procedure  
Participants were individually interviewed in the memory lab by a research assistant. Participants were told that the topic of the research was infantile amnesia and the development of events memory. The researcher began each interview by explaining to the participant that he/she would be asked to describe the first memories from his/her past. The participants were instructed to only tell the researcher about directly experienced events, and not to fill in any blanks with details obtained from family or friends' stories. Experimental questioning in this field is particularly important and it should be stressed to participants that they must only refer to events of which they have a personal memory. As [PERSON] [62; 63] reminds us, adults believe that they remember early events, but, in actual fact, they only know about them from other sources (photos, parents' stories), using information drawn from semantic memory. Specific instructions were provided, as well as practice tests at the beginning of the procedure, to make the nature of the recall tasks clear. We analyzed the memories divided into the two classic epochs of infantile amnesia, in agreement with [PERSON] and [PERSON] [25]. The first epoch was related to the period prior to kindergarten (0-3 years) and the second to the kindergarten years (4-6 years). Please note that kindergarten and primary school refer to codified phases in the life of Italian children. In the Italian school system, the first epoch (0-3) includes educational structures called \"nests\". The kindergarten corresponds to the nursery school and then the elementary school begins. These levels are different both for the architecture of the environments and for the educational roles. Although kindergarten is not mandatory, it always starts at age 3 and, in our research, only children who attended kindergarten were selected. Primary school (formal schooling) is compulsory in Italy for everyone and starts at age 6. The mention of kindergarten as a temporal landmark to prompt the earliest memory is consistent with [PERSON] and [PERSON] [64]. We are aware that this choice involves a difference of months in the age of children. According to the Conway Model of autobiographical memory [65; 66], we believe that a lifetime event as kindergarten is more ecologically valid than age expressed in months. Participants, who were individually tested, were asked to remember specific, personally experienced earliest events with the following question: \"Try to tell me everything you can about your earliest infantile memories, concerning the time before you started kindergarten (i.e., about age 3). The memories must be your own, from your experiences, not something you saw in a picture or heard from someone else.\" Then, a similar question was formulated, but this time regarding \"the time from when you started kindergarten until the beginning of primary school, from the end of 3 to 6 years.\" Particular attention was paid to labelling the two periods with reference to the attendance of the two types of school This element is particularly important because the problem of the correct dating of autobiographical events is well known in the literature (see the telescoping effect [67; 68; 69; 70]). Participants had to report early memories, albeit repeated, incomplete, or poorly defined. If a complete event was remembered, participants were preliminarily informed about the meaning of a \"specific\" event by providing examples: \"we wanted to refer to those single episodes, not repeated, temporally short, lasting less than a day (for example, a birthday party, a game at the stadium, and so on).\"  
In line with previous studies [25; 71], for each memory recalled, we asked the following questions: **How old were** you? (With the date for the memory requested in years); **What** happened? (Activity); **Who** was present? (Self and/or other participants); **Where** did the event take place? (Location); what specific **Emotions** did you experience at that time?