Biases

CONTEXT Scientific research has consistently
shown that prejudicial behaviour may contribute
to discrimination and disparities in
social groups. However, little is known about
whether and how implicit assumptions and
direct contact modulate the interaction and
quality of professional interventions in education
and health contexts.
OBJECTIVES This study was designed to
examine implicit and explicit attitudes towards
wheelchair users.
METHODS We investigated implicit and explicit
attitudes towards wheelchair users in three
different groups: patients with traumatic
spinal cord injury (SCI); health professionals
with intense contact with wheelchair users,
and healthy participants without personal contact
with wheelchair users. To assess the shortterm
plasticity of prejudices, we used a valid
intervention that aims to change implicit
attitudes through brief direct contact with a
patient who uses a wheelchair in an
ecologically valid real-life interaction.
RESULTS We found that: (i) wheelchair users
with SCI held positive explicit but negative
implicit attitudes towards their novel in-group;
(ii) the amount of experience with wheelchair
users affected implicit attitudes among health
professionals, and (iii) interacting with a
patient with SCI who contradicts prejudices
modulated implicit negative bias towards
wheelchair users in healthy participants.
CONCLUSIONS The use of a wheelchair
immediately and profoundly affects how a person
is perceived. However, our findings highlight
the dynamic nature of perceptions of
social identity, which are not only sensitive to
personal beliefs, but also highly permeable to
intergroup interactions. Having direct contact
with people with disabilities might foster positive
attitudes in multidisciplinary health care
teams. Such interventions could be integrated
into medical education programmes to successfully
prevent or reduce hidden biases in a
new generation of health professionals and to
increase the general acceptance of disability in
patients.

This paper compiles a database of radiocarbon dates of archaeological sites that are currently available for the Pampean region. Based on the probability distribution of radiocarbon dates from this database, major temporal trends are defined, taphonomic and scientific biases are evaluated, and their implications for demography are suggested. Results indicate a continuous archaeological signal between ca. 14,500 and 100 cal BP. During the final Late Pleistocene and the Early Holocene, the archaeological signal is low in ca. 14,500-12,800 cal BP, and increases to a moderate and continuous signal in ca. 12,800-7500 cal BP. The archaeological signal for the former lapse correspond to the early peopling of the region and is related to the inhabiting and exploitation of key landforms (e.g., rock shelters, river valleys) and critical resources (e.g., lithic raw material, water). The low amount of available dates for the Middle Holocene (ca. 7400-3700 cal BP), and the associated archaeological signal would be due to the combination of various factors such as taphonomic biases, organization of prehistoric populations, and even a possible low population density. The obtained low but continuous signal for this period are discussed in the framework of the proposed models for the human occupation of the region suggesting that a hypothesis about population extinctions and disruptions processes could not be sustained. Finally, during the Late Holocene (from 3700 to 100 cal BP) human occupations are recorded in all the micro-regions. Regardless of biases, this signal is interpreted as an increase in demographic density at a regional level.