John Kirkland

School Truants and Truancy Motivation Sorted out with Multidimensional Scaling

A combination of established and novel multivariate techniques was applied to the problem of school truancy. Informants described 104 truants they were acquainted with by ranking the applicability of 73 motives and causes for absence from school. Individual rankings were analyzed in the context of a multidimensional representation of the motives, derived from sorting data provided by other informants. Each ranking was interpreted as a three-dimensional vector within this “similarity space” and as a profile of 10 weights indicating the contributions of 10 “hotspots” (broad themes summarizing the motives) located in the space. The broad spectrum of motivational profiles was subdivided using clustering techniques. Five main relatively homogeneous clusters emerged, of which two cover a previously recognized pattern of parent-condoned truancy, whereas the other three are related to recognized syndromes of adolescent delinquency. There may be considerable differences between these clusters in terms of developmental antecedents, prognosis, and most effective form of intervention.

An alternative approach for the analyses and interpretation of attachment sort items

Attachment Q‐Sort (AQS) is a tool for quantifying observations about toddler/caregiver relationships. Previous studies have applied factor analysis to the full 90 AQS item set to explore the structure underlying them. Here we explore that structure by applying multidimensional scaling (MDS) to judgements of inter‐item similarity. AQS items are arranged in the MDS solution along three easily interpretable axes: a model that is compatible with but more parsimonious than factor analysis solutions. This geometrical approach suggests ways to modify the AQS—primarily a research tool—to make it more practical for clinical applications. Sets of AQS data are represented and interpreted in the three‐dimensional model as vectors. Summaries at a finer‐grained level are obtained by finding points in the model where variability across datasets is greatest. We report re‐analyses of archival (published) data, and also data collected with streamlined procedures more suitable in the field. Although not reported here, collection and analysis can both be performed online via a website. The general methodology is not restricted to the current application of toddler attachment.

Classification of infant cries using descriptive scales

Attempts to develop rules for identifying infant cry-types have typically relied on acoustic parameters of “distinctive features”. In the present study rules are developed from Semantic Differential (SD) scales. Twenty-four infant cries (six each of pain, birth, hunger, and pleasure) were rated on 50 SD scales by 39 mothers who also completed a cry recognition task. A discriminant function analysis produced classification equations which correctly identified 82% of the 10 criterion items and 64% of the full cry set. Additionally, scales which discriminated the four cry-types were selected using the mean scale ratings of the better recognized cries. Cry-type descriptions were provided by the scale labels. The discriminant function analysis offers a reliable means for classifying cries according to ratings on SD scales, and the SD scales provide cry-type descriptions.

Maternal Sensitivity: A Review of Attachment Literature Definitions

A tenet of attachment theory (Bowlby, 1969; Ainsworth, Blehar, Waters and Wall, 1978) is that attachments develop within the context of, and are thus influenced by, early interactions. “Sensitivity” has been asserted by many researchers to be the key feature of interactions promoting “secure” attachment relationships. Attachment theorists assume that attachment quality is based on the nature of a caregivers responses to an infants signals for proximity and contact. Although there appears to be broad agreement in the literature on the importance of maternal sensitivity in affecting attachment relationships, writers differ in their definition of “sensitivity” and the relative emphasis placed on particular aspects of parental behaviour in explaining its effect on attachment. This paper reviews the literature addressing the construct of “sensitivity”. The problem of defining this construct will be highlighted by summarising relevant literature and identifying the range of behaviours typically used as indica...

Colour‐vision tests considered as a special case of multidimensional scaling

Panel tests of colour vision such as the D15 and Farnsworth–Munsell 100-Hue tests are designed to classify people into broad categories of normal or deficient colour vision. Our interest lies in finer measurements within these categories. We apply the insights and methods of multidimensional scaling to individuals’ performances on the D15 and 100-Hue tests, by interpreting these as information about the similarities between pairs of the test stimuli (16 and 85 stimuli, respectively). The results are quantitative descriptions of individual performances on the tests. There are implications for more objective test interpretations and diagnosis of colour-vision deficiencies.

Colour-space distortion in women who are heterozygous for colour deficiency

We examined colour perception among a group of women heterozygous for colour vision deficiency. Judgements of colour dissimilarity were collected by presenting colour stimuli in groups of three for odd-one-out decisions. The judgements were summarised as one consensus colour space for the heterozygotes and another for age-matched controls. Individual differences MDS was also applied, resulting in a single colour space which can be adjusted to fit each subjects responses individually by compressing it along its axes. Heterozygous women showed a trend towards colour-space compression in a red-green dimension, or reduced salience of that dimension compared to controls, though less extreme than found in overt colour deficiency.

Escher in color space: Individual-differences multidimensional scaling of color dissimilarities collected with a gestalt formation task

The structure of color perception can be examined by collectingjudgments about color dissimilarities. In the procedure used here, stimuli are presented three at a time on a computer monitor and the spontaneous grouping of most-similar stimuli into gestalts provides the dissimilarity comparisons. Analysis with multidimensional scaling allows such judgments to be pooled from a number of observers without obscuring the variations among them. The anomalous perceptions of color-deficient observers produce comparisons that are represented well by a geometric model of compressed individual color spaces, with different forms of deficiency distinguished by different directions of compression. The geometrical model is also capable of accommodating the normal spectrum of variation, so that there is greater variation in compression parameters between tests on normal subjects than in those between repeated tests on individual subjects. The method is sufficiently sensitive and the variations sufficiently large that they are not obscured by the use of a range of monitors, even under somewhat loosely controlled conditions.

Perceptual Dimensions of Infant Cry Signals: A Semantic Differential Analysis:

In the present study the Semantic Differential technique was used to examine perceived characteristics of infant cry sounds. 24 cries (6 each of pain, hunger, birth, and “pleasure”) were rated by 39 mothers on 50 scales. A factor analysis of the scale ratings uncovered three main factors, labelled Affect, Potency, and Evaluation, respectively. 5 “factorially-pure” scales were selected to represent each factor. A hierarchical cluster analysis of the mean factor-scale ratings uncovered 3 major cry clusters which essentially represented 3 cry-type groups, hunger, pleasure, and pain/birth. A close correspondence was found between this set of clusters and another set generated independently from cry-recognition data, indicating that the semantic differential factor-scales effectively discriminated perceptually distinct cries. This procedure adequately separates the physical (acoustic) properties of signals from their listener-perceived (auditory) ones. This distinction is not possible with studies which depend upon multivariate techniques and casts doubt on their findings.

Sex differences in color vision and the salience of color-space axes

Explanations for the sex difference in colour experience include  Differences in socialisation, e.g. women more attuned to colour in general. This ties in with superior female access to the colour lexicon. It would only make a difference, however, if the Lightness and blue-yellow axes were somehow less affected by the overall lower colour aptitude among males (harder to ignore?).  Genetic influences in retinal performance (e.g. the existence of women possessing four or even five classes of photopigment).  Other differences in physiology (e.g. lower average levels of macular pigment in females — though this would work in the opposite direction to the effect observed here).

Twins and odd‐ones‐out: a twin study of genetic contributions to variability in personal colour space

Background: Individuals differ in the biological substrate of vision, often as a result of genetic differences. There are also subtle variations within the normal population in aspects of colour behaviour (for example, colour naming and unique‐hue judgements) but it is surprisingly hard to connect these to the genetic variation. Perceptions of intercolour similarities (and variations in the structure of colour space, reconstructed from them) may show a closer link to the biological basis of vision.