Introduction 1980 1989 1993 1994 1999 1999 1986 1999 2003 2004 2005 2006 2007 1999 2001 2003 2004 2005 2006 1999 2003 2006 2004 2004 2004 1997 2006 1980 1989 1993 1994 1999 1999 2006 2007 1990 differed 2004 Method Participants Thirty students from Tilburg University received course credits for their participation. All reported normal hearing and normal or corrected-to-normal vision. They were tested individually and were unaware of the purpose of the experiment. The study was carried out along the principles laid down in the Helsinki Declaration and informed consent from the participants was obtained. Stimuli 2 1 Fig. 1 a c b d negative values a b c d  Design Three within-subjects factors were used: exposure lag during the exposure phase (−100 and +100 ms, with negative values indicating that the sound was presented first), location of the sound during exposure (exposure-sound central or lateral) and SOA between the sound and light of the test stimuli (−240, −120, −90, −60, −30, 0, +30, +60, +90, +120, and +240 ms, with negative values indicating that the sound came first). The location of the test sound (central or lateral) was a between-subjects variable. Half of the participants were tested with central test sounds, the other with lateral test sounds. These factors yielded 44 equi-probable conditions for each location of the test sound (2 × 2 × 11), each presented 12 times for a total of 528 trials. Trials were presented in eight blocks of 66 trials each. The exposure lag and the location of the exposure sound were constant within a block, while the SOA between sound and light varied randomly. The order of the blocks was counterbalanced across participants. In half of the blocks with a lateral exposure sound, the sound came from the left, in the other half from the right. The lateral test sounds were presented from the same side as during exposure. Procedure Each block started with an exposure phase consisting of 240 repetitions (∼3 min) of a sound–light stimulus pair (ISI = 750 ms) with a constant lag (−100 or +100 ms) between the sound and the light. After a 2,500 ms delay, the first test trial then started. To ensure that participants were fixating the light during exposure, they had to detect the occasional occurrence of the offset (150 ms) of the fixation light (i.e., a catch trial). Participants then pushed a special button. The test phase consisted of two parts: a short AV re-exposure phase followed by three AV test trials of which the temporal order of the sound and light had to be judged. The re-exposure phase consisted of a train of ten sound-light pairs with the same lag, ISI, and sound location as used during the immediately preceding exposure phase. After 1 s, the three AV test trials were presented with a variable SOA between the sounds and lights. The participant’s task was to judge whether the sound or the light of the test stimulus was presented first. An unspeeded response was made by pressing one of two designated keys on a response box. The next test stimulus was presented 500 ms after a response, and the re-exposure phase of the next trial started 1,000 ms after the response on the third test stimulus. To acquaint participants with the TOJ task, experimental blocks were preceded by four practice blocks in which no exposure preceded the test trials. The first two practice blocks were to acquaint participants with the response buttons, and consisted of 16 trials in which only the largest SOAs were presented (±240 and ±120). During this part, participants received verbal feedback (“correct” or “wrong”) about whether they gave the correct response or not. The next two practice blocks consisted of 66 trials in which all SOAs were presented 6 times randomly without verbal feedback. Total testing lasted approximately 2.5 h. Results Trials of the practice session were excluded from analyses. The proportion of “light-first” responses was for each participant calculated for each combination of exposure lag (−100, +100 ms), location of the exposure sound (central, or lateral), location of the test sound (central, or lateral) and SOA (ranging from −240 to +240 ms). Performance on catch trials was flawless, indicating that participants were indeed looking at the fixation light during exposure. For each combination of exposure lag, location of the exposure sound and location of the test sound, an individually determined psychometric function was calculated over the SOAs by fitting a cumulative normal distribution using maximum likelihood estimation. The mean of the resulting distribution (the interpolated 50% crossover point) is the point of subjective simultaneity (henceforth the PSS), and the slope is a measure of the sharpness with which stimuli are distinguished from one another. The slope is inversely related to the just noticeable difference (JND) and represents the interval (absolute SOA) at which 25 and 75% visual-first responses were given. 2 1 Fig. 2 V-first  Table 1 Mean points of subjective simultaneity (PSSs) in ms, and mean just noticeable differences (JND) in parentheses Location test sound  Location of the exposure sound Central  Lateral AV-lag (ms) PSS (JND) TRE PSS (JND) TRE Central −100 −12.5 (39.3) 14.5 −9.9 (37.8) 6.4 100 2.0 (40.8)  −3.5 (38.6)  Lateral −100 6.1 (38.2) 14.2 −14.3 (36.4) 16.8 100 20.3 (36.1)  2.5 (42.0)  Exposure stimulus pairs were presented with an auditory–visual Lag (AV-lag) of −100 and +100 ms with sounds either central or lateral; the location of the test stimulus sound was either central or lateral. The temporal recalibration effect (TRE) reflects the difference in PSSs between the −100 and +100 ms audio–visual lags P F P 1 F P F Discussion 2007 2006 spatial 1966 1978 1978 1981 1994 1999 1994 2001 2003 1908 2001 2005 2001 2003 2005b 2003 2003 2003a b 2005a 2005 fused extra spatial cues 2003 2006 2007 1992 2001