In line with our subjective essentialist view of stereotypes (Yzerbyt, Rocher, & Schadron, 1997), we propose that two classes offactors that mutually reinforce each other influence the perception ofgroups. The perception ofa strong level ofsimilarity and organization among group members (i.e., group entitativity) suggests the existence ofa deep essence that would account for the detected regularities. Conversely, the existence ofnaive theories regarding the presence ofan underlying core encourages the searchfor resemblances and connections within the group. After a shortpresentation of the recent literature dealing with the concepts of entitativity and essentialism, we review a series ofstudiesfrom our laboratory showing the impact of entitativity on essentialism as well as the influence of essentialism on entitativity. We also provide empirical evidence for this bidirectional process from both the outsider and the insider perspective. Finally, we examine the potential role of cultural differences both in the ascription ofafundamental nature to an entitative assembly ofpeople and in the use ofa priori naive theories to create surface similarity among group members. As a set, these efforts point to the importance oftaking into account the constant dialogue between perceivers' theory-based explanations and group members' perceptual characteristics if one wishes to understand group stereotypes.

No abstract

Depression and seasonal sensitivity among medical students residing in high southern latitudesBackground: There is no evidence for the association of depressive symptoms with the sense of well-being of undergraduate medical students residing in high southern latitudes (HSL). Aim: To assess the frequency of depressive symptoms and its relationship with seasonal sensitivity and quality of life in medical students residing in HSL. Material and Methods: The Beck anxiety and depressive symptoms inventory, the seasonal pattern assessment questionnaire and the quality-of-life questionnaire of the WHO were applied to 102 medical students residing in Magallanes, Chile. Results: Fifty-two percent of respondents reported some degree of depressive symptoms. These symptoms were significantly associated with the seasonal pattern score (r = 0.432, p < 0.01). They were also inversely associated with parameters of physical health and psychosocial health (r = -0.567, p < 0.01 and r = -0.708, p < 0.01, respectively). There was also a correlation between depressive and anxiety symptoms. Conclusions: Depressive symptoms are common in medical students residing in HSL and they are associated with seasonal sensitivity and quality of life measures.

Objective: This study determines the relationship between the fatigue of adolescent swimmers in high-level competitions during two continuous periods of maximum performance and the degree that swimmers conform to norms during these periods. Methods: We evaluated the conformist trait and three areas of fatigue in two consecutive competitive periods, in 25 young elite swimmers. The measures were evaluated before (_B) and after (_A) of pre (t1; t3) and pos (t2; t4) competition in each period. Millon Adolescent Clinical Inventory was applied for identifies the more adherens (AD; n=12) or detached from the norm (DN; n=13) conformist traits. Wingate test, Heart rate variability (RMSSD; SDNN), WISC-V, and Stroop test were evaluated. Results: DN group present lower fatigue in t1 but an increase in t2, t3, and t4. AN present higher RMSSD_B and SDNN_B in t1. In t3, the mental fatigue of DN was correlated negatively with RMSSD_B; SDNN_B. Both groups had more SDNN_B than SDNN_A in t4. Conclusions: Physical fatigue was important conditioning in both groups, however, the DN group may be more sensitive to physiological and mental fatigue directly affecting the performance.

Objetivo: este estudio tuvo como propósito, determinar la existencia de una asociación entre el índice de masa corporal y la regulación cardiovascular en estudiantes de medicina. Materiales y métodos: Estudio transversal con un diseño aleatorio. La muestra se compuso por 54 estudiantes de medicina (21,2 ± 1,6 años) que fueron evaluados y clasificados según el índice de masa corporal: Normopeso (NP; IMC < 25 kg/m2); Sobrepeso (SP; IMC≥ 25 kg/m2); Obesos (OB; IMC a 30 Kg/m2). Medidas antropométricas, presión arterial y variabilidad de frecuencia cardiaca (HRV) fueron las variables evaluadas. Resultados: 51,9% de los estudiantes presenta sobrepeso u obesidad. El índice de masa corporal correlaciona negativamente con el parámetro de variabilidad de frecuencia cardíaca, especialmente al compararla en los dominios de tiempo de HRV (p<0,001). También se observaron diferencias en el control autonómico cardíaco al comparar los grupos de estudio en LnRMSSD (p<0,01) y LnSDNN (p<0,01). Conclusión: los estudiantes de medicina que presentan mayor índice de masa corporal se asocian a un menor control autonómico cardíaco y menor acción parasimpática en la regulación del sistema cardiovascular.