Krista Phillips

Effects of estrogen changes during the menstrual cycle on spatial performance

Abstract Four sequential, interrelated studies of the relationship of menstrual cycle phase to three-dimensional mental rotations performance were conducted, using both between-and within-subjects designs. All studies showed significant increases in mean mental rotations scores during the menstrual period phase, when estrogen levels were at their lowest. Effects occurred only for mental rotations; relationships with hormonal status did not occur for control tests, which were not of a spatial nature, and a different spatial test (Space Relations). Findings are discussed as they relate to ontogenetic development and evolutionary origins of sex-specific differences in spatial behaviors.

Testosterone levels and spatial ability in men

Testosterone (T) levels were measured by salivary assays in 59 males at times of the day when T was expected to be highest and lowest. Relationships were evaluated for mean hormone levels across the two sessions and hormone level changes between sessions with performance on three-dimensional mental rotations, a spatial test which customarily favours males. An anagrams task and the digit symbol test were used as controls. Mental rotations scores showed a significant positive relationship with mean T levels but not with changes in T. There were no significant relationships between control test scores and mean T levels. Findings are discussed in terms of their contributions to the resolution of ambiguities in prior reported data.

Possible olfaction-based mechanisms in human kin recognition and inbreeding avoidance.

Three studies explored kin recognition through olfaction. In Study I, adults (N=22) were tested for ability to identify the odors of themselves; their mother; their father; a sister; a brother; a familiar, unrelated individual; and a stranger. Acquaintances were identified as accurately as biological kin, implicating an association mechanism. However, biological kin were often confused, implicating phenotypic matching. Same-sex kin were confused more than opposite-sex kin, but mainly when same-sex kin had odors of similar intensity. Study II implicated phenotypic matching. Mothers (N=18) could identify their biological children but not their stepchildren. The preadolescent children (N=37) identified their full siblings but not half-siblings or stepsiblings. Thus, olfactory cues may help mediate favoritism of blood relatives. In Study III, mutual olfactory aversion occurred only in the father-daughter and brother-sister nuclear family relationships. Recognition occurred between opposite-sex siblings but not same-sex siblings. Thus, olfaction may help mediate the development of incest avoidance during childhood (the Westermarck effect).

Differences in the Relationship of Menstrual Cycle Phase to Spatial Performance on Two- and Three-Dimensional Tasks ☆ ☆☆

Inverse activational effects of estrogen on spatial problem-solving performance in females have been amply demonstrated, although the findings across studies are somewhat inconsistent. In an attempt to resolve this ambiguity, the present study compared activational effects, using phases of the menstrual cycle as the criteria for estrogen levels, on two- and three-dimensional spatial tasks. As predicted, menstrual cycle effects were obtained for the latter category only. Results were interpreted as a function of the greater ecological validity of three-dimensional tasks.

Homogeneity of Effect Sizes for Sex across Spatial Tests and Cultures: Implications for Hormonal Theories

Japanese and Canadian samples were compared on two spatial test which typically show higher male scores but tend to differ in the magnitude of the sex difference. Sex differences, both in terms of direction and magnitude, were similar between cultures. Results are discussed in terms of their relevance for hormonal theories of spatial sex differences.

Sensitivity to the cognitive and affective qualities of odours

This study examined cognitive and emotional responses to odours in the laboratory in relation to everyday attitudes toward odours. A total of 136 subjects completed a questionnaire about the role of Odours in Everyday Life (OELQ) and their responses were summed to develop an index of overall responsiveness to odours: 36 subjects, who were in the top and bottom quartiles on this index, rated pleasant (e.g., rose) and unpleasant (e.g., synthetic sweat) odours in the laboratory on 7-point scales. Separate factor analyses were done for the OELQ items and the laboratory ratings, and these factors were intercorrelated. The factor analysis on the OELQ data yielded three primary factors, encompassing the Sexual Role of Bodily Odours, Ecological Odour Sensitivity, and Odour-evoked Memories, as well as three secondary factors. Two factors were derived from the laboratory ratings contrasting Cognitive (sensations, images, memories) and Affective (pleasant, soothing, energising) Responses. Correlations among the factors showed that Ecological Odour Sensitivity in everyday life was correlated with strong Cognitive but weak Affective Responsiveness to the laboratory odours. In contrast, the Sexual Role of Bodily Odours (OELQ) was positively correlated with Affective Responses to the odours in the laboratory. These data underscore the dual role of odours in stimulating cognitive and affective reactions both in everyday life and in the laboratory.

The scent of literature

This study examined the effects of hedonic odour context on cognitive and affective processes involved in reading literary excerpts. A total of 32 undergraduate subjects smelled pleasant and unpleasant odours, while reading eight passages that touched upon positive or negative subject matter and were either engaged or detached in style, in a fully counterbalanced within-subjects design. After each reading episode, subjects rated passage and odour on fourteen 7-point scales. In accordance with a hedonic congruence hypothesis, odours should affect the reading process when there was a fit between the hedonic tone of the textual properties (subject matter or style) and the odours (pleasant/unpleasant). Results supported this hypothesis showing that positive subject matter and engaged style combined with pleasant odour to bring the story to life and evoke the most images and feelings. Passages with negative subject matter were not readily affected by the hedonic odour context. These findings replicated earlier research involving paintings viewed in a hedonic odour context. Gender differences also revealed that males, compared with females, found episodes read in the context of unpleasant odours to be more involving and personally meaningful, and they could more readily identify with the characters.

Scented memories of literature.

This study examined the effects on recall of story details of congruity or incongruity between the hedonic valence of literary texts and odours inhaled while reading them. During the reading session, 24 undergraduates (12 males and 12 females) read two passages involving positive subject matter and two with negative subject matter while sniffing pleasant or unpleasant odours in a within‐subject fully counterbalanced design. Subjects rated their experience of each text on eleven 7‐point scales. During the test session 48 hours later, subjects read a two‐word title associated with each of the passages and inhaled the odour that was paired with it in the reading session. They also rated their experience on six of the scales that had been used during the reading session. Results showed that hedonic congruence between the passage and the odour fostered enhanced recall during the test session. The combination of positive subject matter and positive odour was reflected in more accurate recall of character details, while pairing negative subject matter and negative odour resulted in more accurate recall of setting details. Regression analysis showed that overall recall accuracy was increased by identifying with the characters in the stories and for passages that were found pleasing and personally meaningful. Consistent with the literature on implicit learning involving odours, recall accuracy varied inversely with perceived odour intensity. Implicit learning involving odours and literary passages is therefore fostered by unity in the reading experience.