Causal explanations for age bias may draw from varied theoretical accounts. These include neoliberal accounts based in economics, political economy perspectives emphasizing industrial change and flexible labor markets, and post-modern arguments tied to the breakdown of cultural values and social groups (Wood et al., 2008). From a public policy perspective, however, among the most influential explanations for older age bias are accounts derived from the research of industrial and organizational psychologists. Described variously as the problem of ageism, prejudice, stereotyping, or implicit bias, unfounded assumptions about older workers and their corresponding ill effects are justifications articulated by policymakers and courts for the prohibition of age discrimination in employment (Bisom-Rapp and Sargeant, 2013). Despite the ubiquity of a psychologically based rationale for legal regulation, deficiencies in the construction and application of legal doctrine, and the recent experience of older workers during the global economic crisis (Bisom-Rapp et al., 2011; Neumark and Button, 2013) raise important questions about the sufficiency of employment discrimination law as protective armor for an aging workforce. Drawing on the authors' previous work, this chapter addresses these matters as follows. First, the chapter lays out a relatively simple account of older age bias derived from the psychological literature and highlights its strong tie to age discrimination law. The chapter proceeds to reveal that bias against older workers is a complex phenomenon that may play out in a manner difficult to discern for the purpose of legal claiming. The chapter then describes the way in which the law in our respective countries (the United Kingdom (U.K.) and the United States (U.S.)) provides incomplete protection to older workers from those complex effects. Our chapter concludes with some suggestions for reform. BURKE 9781783476572 (M3696) (G).indd 97 22/04/2015 16:13 98 The multi-generational and aging workforce AN ACCOUNT FROM INDUSTRIAL AND ORGANIZATIONAL PSYCHOLOGY ANIMATES LAW Early accounts of the problem of older age bias reference the problem of ageism. The first use of the term is attributed to Dr. Robert Butler, who in 1969 wrote about the strongly negative reaction of white affluent middleclass residents to a proposal for a public housing project for the elderly poor in Chevy Chase, a neighborhood in northwest Washington, DC. Butler described ageism as "prejudice by one age group against other age groups" (Butler, 1969). A more comprehensive and contemporary definition is contained in a 2009 United Nations (U.N.) report on aging, which describes ageism as encompassing systemic, negative stereotyping and discrimination or denial of opportunities on the basis of age. The report notes that ageism "reinforces a negative image of older persons as dependent people with declines in intellect, cognitive and physical performance. .. [O]lder persons are often perceived as a burden, a drain on resources, and persons in need o...