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2013 - Volume 34, Number 1, Winter

The Use of the Classical Twin Method in the Social and Behavioral Sciences: The Fallacy Continues

The classical twin method assesses differences in behavioral trait resemblance between reared-together monozygotic and same-sex dizygotic twin pairs. Twin method proponents argue that the greater behavioral trait resemblance of the former supports an important role for genetic factors in causing the trait. Many critics, on the other hand, argue that non-genetic factors plausibly explain these results. The twin method has been used for decades in psychology, psychiatry, and medicine, and more recently in social science fields such as political science and economics. In 2012, a team of researchers in political science using behavioral genetic methods performed a study based on twin data in an attempt to test the critics’ position, and concluded in favor of the validity of the twin method and its underlying monozygotic–dizygotic “equal environment assumption.” The author argues that this conclusion is not supported, because the investigators (1) framed their study in a way that guaranteed validation of the twin method, (2) put forward untenable redefinitions of the equal environment assumption, (3) used inadequate methods to assess twin environmental similarity and political ideology, (4) reached several conclusions that argue against the twin method’s validity, (5) overlooked previous evidence showing that monozygotic twin pairs experience strong levels of identify confusion and attachment, (6) mistakenly counted environmental effects on twins’ behavioral resemblance as genetic effects, and (7) conflated the potential yet differing roles of biological and genetic influences on twin resemblance. The author concludes that the study failed to support the equal environment assumption, and that genetic interpretations of twin method data in political science and the behavioral science fields should be rejected outright.

Correspondence concerning this article should be addressed to Jay Joseph, Psy.D., P.O. Box 5653, Berkeley, California 94705–5653.

Explaining Consciousness: A (Very) Different Approach to the “Hard Problem”

This article addresses what Chalmers called the “hard problem” of explaining consciousness – the problem of experience – in the context of a mediation brain theory in which consciousness is a fundamental feature of physical matter. It presents a novel explanation of how mind-to-brain transmission operates in a way that accounts for the existence of conscious experience. The article explains what is meant by a protoconsciousness inherent in things, its properties and genesis, and how this consciousness accumulates. How consciousness inherent in matter relates to a range of personal identity issues is also discussed. Bold scientific hypotheses and even bolder metaphysical theories are needed to advance the present state of discussion of the problem of how and why brain activity is accompanied by conscious experience.

Correspondence concerning this article should be addressed to Paul F. Cunningham, Ph.D., Rivier University, Nashua, New Hampshire 03060–5086.

Psychotherapy and the Brain: The Dimensional Systems Model and Clinical Biopsychology

The dimensional systems model explains cortical processing on the basis of cortical column interactions, leading to a clinical biopsychological model which involves brain-based psychotherapy integration. The current paper provides a detailed explanation of the interface between these models in relation to psychological treatment. A specific discussion of certain psychotherapy treatment approaches is provided with suggestions on what cortical areas are being impacted. In reference to negative emotional memories there are specific, theoretically based suggestions on how to most effectively neutralize the continuing impact on a client’s current psychological functioning. Loss-related depression is explained on the basis of opponent-process theory as related to the brain model. It is hoped that this paper can generate interest among neuroscientists and clinicians to fully evaluate the value of these theoretical models.

Correspondence concerning this article should be addressed to Robert A. Moss, Ph.D., Bon Secours St. Francis Hospital, 1 St. Francis Drive, Greenville, South Carolina 29601. Email:

The Flow of Time as a Perceptual Illusion

This article discusses theories and evidence on the flow of time as a perceptual illusion. The flow of time is said to be a stubborn illusion, although it has never been experimentally verified. There is a high-level flow of time (the experiential phenomenon of the past, present, and future), as well as a low-level flow of time, happening, which includes spatial change (motion). The hypothesis is that the latter, happening, component of the flow of time is a perceptual illusion. Previous research reveals that motion perception occurs in discrete processing epochs, frames, or snapshots. Apparent motion is painted onto each snapshot, and motion is not experienced because of a change in position between two consecutive snapshots but is represented within a single snapshot. When people view video scenes of a walking man and toasting bread with a wide range of interstimulus intervals, fewer of them could “see it happening” as the interstimulus interval was increased. This suggests that happening, whether involving a color change or a motion, is a frequency-dependent percept. It can be eliminated, for example, by choosing the appropriate stimulus frequency. The low-level component of the flow of time is therefore a perceptual illusion.

Correspondence concerning this article should be addressed to Ronald P. Gruber, M.D., Stanford University Medical Center, Stanford, California 94305. Email:

Book Reviews

Clinical Psychology: An Introduction
Book Author: Alan Carr. New York: Routledge, 2012, xviii+395 pages, $39.95 paperback, $150.00 hardcover.
Reviewed by Geoffrey L. Thorpe, University of Maine

Alan Carr directs the clinical psychology training program at University College Dublin. He wrote Clinical Psychology: An Introduction to introduce undergraduate students to clinical psychology as a profession, covering psychological assessment, the leading models of psychotherapy, a selection of topics within psychopathology, and the scientific evidence supporting current interventions. One of the five learning objectives for the first chapter, “What is Clinical Psychology?,” is to enable students to plan their careers so as to increase the likelihood that they will qualify for admission to a clinical psychology graduate program. Carr focuses upon the 30 doctoral programs in England, Scotland, and Wales and the five in the Republic of Ireland and Northern Ireland.

Correspondence concerning this book review should be addressed to Geoffrey L. Thorpe, Psychology Department, Room 372, 5742 Little Hall, University of Maine, Orono, Maine 04469–5742. Email:

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