This study uses an experimental design to simulate the ballot counting process during a hand-recount after a disputed election. Applying psychological theories of motivated reasoning to the political process, we find that ballot counters' party identification conditionally influences their ballot counting decisions. Party identification's effect on motivated reasoning is greater when ballot counters are given ambiguous, versus specific, instructions for determining voter intent. This study's findings have major implications for ballot counting procedures throughout the United States and for the use of motivated reasoning in the political science literature.

Michele Acker Robert Arkin Michael Baysinger Bianca Beersma Michael Bernstein Eileen Braman Sara Branch Sarah Bryner Jerry Burger Dustin Carnahan Boğaçhan Çelen Jonathan Cheek Chris Crandall Eveline Crone Sonya Dal Cin Nicholas DiFonzo Paul Eastwick Kelly Garrett B.A. Gladue Nicholas Goedert Rich Gramzow Melanie Green Steve Harkins Helen Harton Allyson Holbrook Steve Karau Norbert Kerr Amna Kirmani Eric Knowles Dan Levin Timothy Levine Dana Mastro Monique Mitchell Turner Saar Mollen Michael Norton Petia Petrova T. Andrew Poehlman Tom Postmes Priyali Rajagopal Sekar Raju Rajiv Rimal Jason Rose Randall Rose Brad Sagarin Daan Scheepers Erica Schneid Michael Slater Eliot Smith Kristin Sommer Diederik Stapel Mariëlle Stel Eric van Dijk Gerben van Kleef Andrew Ward Ladd Wheeler Xinyue Zhou

Fairness requires that election ballots be counted in an accurate and consistent manner, yet close elections are decided often by hand-recounts that may introduce partisan bias. Using an experimental design, this paper simulates the process of counting challenged ballots during a hand-recount after a disputed election. Applying psychological theories of motivated reasoning to the political process, we find that ballot assessment often hinges on the individual's party identification and the personal stake that he or she has in the outcome of the race. The effect of partisanship on motivated perception is greater when ballot counters are given ambiguous, rather than specific, instructions for determining voter intent. The results of this paper have serious implications for the electoral process and recount procedures.

Japanese knotweed is a serious invasive weed in the UK, North America and large parts of Europe. Current control measures are difficult to implement, unreliable and expensive. In 2003, a classical biological control programme was initiated, one that could lead to the first ever authorised release of a biocontrol agent against a weed in the European Union. Literature studies and surveys in the Japanese native range revealed over 180 species of arthropod natural enemies but only a psyllid, Aphalara itadori, has reached the point of official assessment for release. Aphalara itadori passes from egg to adult through five nymph stages in just under 33 days at 23oC and the timing and physical appearance of these stages is presented. Multiple-choice oviposition studies using 87 species/varieties of test plants showed that only 1.52% of 146,885 eggs were laid outside what we call the invasive knotweed group. None of these eggs laid on non-targets plants were able to develop to adult, however, subsequent nymph transfer experiments revealed limited development on some closely related members of the Polygonaceae and the development to adult on Meuhlenbeckia complexa (7% of cases). Adult survival, used as a surrogate for feeding tests, further revealed that survival on non-targets was severely compromised. These results coupled with an assessment of likely overwintering habits show A. itadori to have a narrow physiological and behavioural host range making it an ideal candidate for the first official release of a classical biological control agent against an alien invasive weed in the European Union.