Volume Preface
ixThis volume is intended to provide thorough, accessible tuto-
rials on the major topic areas in the field of experimental psy-
chology. The volume should be useful not only as a reference
source for professionals, being part of this Handbook,but
also as an effective, stand-alone textbook for students. Con-
sequently, the volume is aimed at professional psychologists,
entry-level graduate students, and advanced undergraduates
who have some relatively limited background in experimen-
tal psychology. Just as reading this volume does not depend
on reading the other volumes in the series, reading a specific
chapter in this volume is not contingent on reading any other
chapters. Each chapter provides an up-to-date, state-of-the-
art review of a specific subfield of experimental psychology,
providing coverage of what is known and what is currently
being done, along with some of the historical context.
WHAT IS EXPERIMENTAL PSYCHOLOGY?
The experimental method is defined by the manipulation of
independent variables and the measurement of dependent
variables. Extraneous variables are either controlled or al-
lowed to vary randomly. In particular, care is taken to remove
any variables that are confounded with the independent vari-
ables. Because of the control exerted, this method permits the
investigator to isolate causal relations. Any change in the de-
pendent variables can be viewed as caused by the manipula-
tion of the independent variables.
Experimental psychology has a rich heritage that started
when Wilhelm Wundt created the first psychology laboratory
in 1879 at the University of Leipzig. Because of the unique
ability to draw causal inferences with experiments, early psy-
chology was essentially experimental psychology. Although
there are certainly those who think that the experiment is the
wrong methodology for many aspects of psychology, the pri-
mary methodological goal of most research in psychology
has been the exertion of as much control as possible, so that
the general idea of the experiment as the ideal research tool is
widely accepted in psychology.
Today the term experimental psychologydoes not, how-
ever, cover all of the areas in psychology that employ the
experimental method. The use of experiments is widespread,
including, for example, research in biological, social, devel-
opmental, educational, clinical, and industrial psychology.
Nevertheless, the term experimental psychologyis currently
limited to cover roughly the topics of perception, perfor-
mance, learning, memory, and cognition. Although by
definition empirical in nature, research on experimental psy-
chology is focused on tests of theories, so that theoretical and
experimental objectives and methods are necessarily inter-
twined. Indeed, research in experimental psychology has be-
come progressively more interdisciplinary, with an emphasis
on not only psychological theories but also theories based on
other disciplines including those in the broader fields of
cognitive science and neuroscience. In addition, since its in-
ception there has been a continued growth and relevance of
experimental psychology to everyday life outside of the lab-
oratory. The potential applications of the results of psychol-
ogy experiments are increasingly widespread and include, for
example, implications concerning teaching and training, law,
and medicine.ORGANIZATION OF THE VOLUMEIn covering the core topics of perception, performance,
learning, memory, and cognition, the volume is organized ap-
proximately from the least to the most complex processes.
Each of the first 23 chapters is focused on a different single or
pair of psychological processes. These chapters are divided
into eight sets with three chapters in each set but the last,
which includes only two. The sets cover the more general
topics of (a) modulatory processes, (b) sensory processes,
(c) perceptual processes, (d) human performance, (e) elemen-
tary learning and memory processes, (f ) complex learning
and memory processes, (g) language and information pro-
cessing, and (h) thinking.
Within the set of modulatory processes, we begin with
the fascinating topic of consciousness (and its inverse, un-
consciousness), which has deep roots in philosophy as well
as in psychology. From there we delve into the topic of mo-
tivation and then the topic of mood. In addressing sensory